Patent Publication Number: US-11660956-B2

Title: Tank mounting structure and vehicle

Description:
INCORPORATION BY REFERENCE 
     This application is a continuation of U.S. patent application Ser. No. 16/160,039, filed Oct. 15, 2018, which claims priority from Japanese Patent Application No. 2017-228838 filed on Nov. 29, 2017 including the specification, drawings and abstract which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     1. Technical Field 
     The disclosure relates to a tank mounting structure and a vehicle. 
     2. Description of Related Art 
     In Japanese Unexamined Patent Application Publication No. 2005-119595 (JP 2005-119595 A), a structure is disclosed in which a protector that covers a rear side of a tank body is provided in a rear axle of a vehicle in order to mitigate an impact on the tank that stores gas used for a fuel cell. 
     SUMMARY 
     Normally, a tank expands and contracts depending on an amount gas stored. Therefore, in the configuration described in JP 2005-119595 A, when the tank contracts, a gap between the tank and the protector can expand. Also, when the protector receives force from outside in a state where a foreign object such as a large stone is trapped in the expanded gap, a portion of the tank that is in contact with the trapped foreign matter receives force locally. As a result, the tank can be damaged. Therefore, a technology has been desired that prevents expansion of the gap between the tank and the protector. 
     It is possible to carry out the disclosure in the following aspects. 
     According to an aspect of the disclosure, a tank mounting structure is provided. The tank mounting structure includes a frame, a band, and a tank protector. The frame is configured to fix the tank. The band is configured to fix the tank in a state where the band sandwiches the tank with the frame and the band deforms in accordance with expansion or contraction of the tank. The tank protector is configured to be fixed to an inner side of the band or an outer side of the band. With the tank mounting structure according to the aspect, since the tank protector and the band are fixed to each other, the tank protector moves according to expansion or contraction of the tank. Thus, it is possible to restrain expansion of a gap between the tank and the tank protector. 
     In the tank mounting structure according to the aspect, the tank protector includes a center member and end portion members. The center member is provided on an outer side of a cylinder portion that is a cylindrical portion of the tank. The end portion members are provided on outer sides of dome portions, respectively. The dome portions are on both end sides of the cylinder portion of the tank, respectively. The end portion members may be thicker than the center member. With the tank mounting structure according to the aspect, the dome portions with relatively small strength are selectively protected by the end portion members, respectively. At the same time, by reducing the thickness of the center member so as to be thinner than the end portion members, it is possible to reduce a weight of the tank protector. 
     In the tank mounting structure according to the aspect, shear strength of the tank protector may be greater than shear strength of the band. Also, the mounting structure may be configured such that an end portion of the band is fixed to the frame while applying pressing force to the tank by using an elastic body. Further, the band may be made from metal. Furthermore, the band may be made from an elastic resin material. Further, lower ends of the end portion members of the tank protector may be positioned so as to be lower than a lower end of the center member of the tank protector. 
     It is possible to carry out the disclosure in various aspects. For example, it is possible to carry out the disclosure in an aspect such as a vehicle having the tank mounting structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG.  1    is a view of a vehicle having a tank mounting structure as an embodiment of the disclosure; 
         FIG.  2    is a sectional view of a tank; 
         FIG.  3    is a perspective view of the tank mounting structure for the vehicle; 
         FIG.  4    is a sectional view of the tank mounting structure in a cylinder portion of the tank; and 
         FIG.  5    is a sectional view of the tank mounting structure in a dome portion of the tank. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     A. Embodiments 
       FIG.  1    is a view of a vehicle  100  having a mounting structure of a tank  60  as an embodiment of the disclosure. In the embodiment, a fuel cell vehicle is used as the vehicle  100 . Description regarding directions in the vehicle  100  (“right”, “left”, “front”, “rear”, “upper”, and “lower”) indicates directions based on a driver who is in the vehicle  100 , respectively. In  FIG.  1   , an X axis forward direction indicates a vehicle front direction, a Y axis forward direction indicates an upper side of the gravity direction, and a Z axis forward direction indicates a vehicle right direction. This means that the X axis direction indicates a front-rear direction of the vehicle, the Y axis direction indicates the gravity direction, and the Z axis direction indicates a width direction of the vehicle. The X, Y, and Z axes are the same in the drawings after  FIG.  1   . 
     The vehicle  100  includes a fuel cell stack  10  and the tank  60 . The fuel cell stack  10  is made by laminating power modules, for example, each of which has a membrane electrode assembly (MEA) in which both electrodes, an anode and a cathode, are joined to both sides of an electrolyte film, respectively. Power is generated in the fuel cell stack  10  due to an electrochemical reaction between hydrogen gas as fuel gas supplied from the tank  60 , and oxygen in the atmosphere. In the embodiment, the fuel cell stack  10  is disposed in a front part of the vehicle  100  (on a +X axis direction side). Specifically, in the front-rear direction (the X axis direction) of the vehicle  100 , the fuel cell stack  10  is disposed at a position where the fuel cell stack  10  partially overlaps front wheels FW. 
     In the embodiment, the tank  60  is disposed in the rear part of the vehicle  100  (on a −X axis direction side) along the width direction of the vehicle  100  (the Z axis direction). Specifically, in the front-rear direction (the X axis direction) of the vehicle  100 , the tank  60  is disposed at a position where the tank  60  partially overlaps rear wheels RW and the remaining part of the tank  60  is at the rear of the rear wheels RW. 
       FIG.  2    is a sectional view of the tank  60 . In the embodiment, the tank  60  includes a liner  62  and a reinforcing layer  64 . 
     The liner  62  of the tank  60  is an airtight container that stores fluid. As a material of the liner  62 , for example, aluminum, stainless steel, and resin may be used. The liner  62  includes cap portions  61  on both end sides in the longitudinal direction, respectively. Each of the cap portions  61  plays a role as a pipe when gas is stored in the liner  62 . In the embodiment, depending of a filling amount of hydrogen gas inside the tank  60 , an outer diameter of the tank  60  changes by between about 1 mm and about 2 mm. 
     The reinforcing layer  64  of the tank  60  is a layer that is formed by winding a resin-impregnated fiber bundle around a surface of the liner  62 . The reinforcing layer  64  is provided in order to improve strength of the tank  60 . In the embodiment, carbon fiber is used as fiber used for the reinforcing layer  64 . 
     In the embodiment, the tank  60  includes a cylinder portion  11  that has a cylindrical shape and is formed in a center portion, and almost hemispherical dome portions  12  provided on both end sides of the cylinder portion  11 , respectively. Normally, since the reinforcing layer  64  tends to become thinner in a part of each of the dome portions  12 , the cylinder portion  11  tends to have higher strength compared to the dome portions  12 . 
       FIG.  3    to  FIG.  5    are views of a mounting structure of the tank  60  for the vehicle  100 .  FIG.  3    is a perspective view of the mounting structure of the tank  60  for the vehicle  100 .  FIG.  4    shows a section taken along the line IV-IV in  FIG.  3   , and is a sectional view of the mounting structure in the cylinder portion  11  of the tank  60 .  FIG.  5    shows a section taken along the line V-V in  FIG.  3   , and is a sectional view of the mounting structure in the dome portion  12  of the tank  60 . The mounting structure of the tank  60  includes frames  70 , bands  80 , and a tank protector  90 . 
     The frames  70  are members used in order to fix the tank  60  (see  FIG.  3   ). In the embodiment, the frames  70  are provided below (on a −Y axis direction side of) the tank  60  and along the front-rear direction (the X axis direction) of the vehicle  100 . In the embodiment, the two frames  70  are provided in parallel to each other below the cylinder portion  11  of the tank  60 . 
     As shown in  FIG.  4   , in the embodiment, both ends of each of the frames  70  in the front-rear direction (the X axis direction) are fastened to a lower surface of an underbody  20  of the vehicle  100  by brackets  22  and bolts  21 , respectively. In the embodiment, a center portion of the frame  70  is bent along the shape of the tank  60  and has a shape that is depressed downwardly. 
     The bands  80  are members that fix the tank  60  in a state the bands  80  sandwiches the tank  60  with the frame  70  and the bands  80  deform in accordance with expansion or contraction of the tank  60  (see  FIG.  3   ). In the embodiment, each of the bands  80  is provided on an upper side (a +Y axis direction side) of the cylinder portion  11  of the tank  60 , and has a shape that extends in the front-rear direction of the vehicle  100  (the X axis direction). In the embodiment, the two bands  80  are provided in parallel to each other. In the embodiment, the bands  80  are bent along a circumference of the tank  60 . 
     As shown in  FIG.  4   , in the embodiment, an end portion of each of the bands  80  on the rear side (the −X axis direction side) of the vehicle  100  is fixed to the frame  70  through a hinge  82  and a bolt  83 . Further, an end portion of each of the bands  80  on the front side (the +X axis direction side) of the vehicle  100  is fixed to the frame  70  by the bolt  83  while applying pressing force to the tank  60  using a spring  84 . With the structure, the bands  80  fix the tank  60  in the state where the bands  80  sandwich the tank  60  with the frames  70  and the bands  80  deform in accordance with expansion or contraction of the tank  60 . In the embodiment, the bands  80  are made from metal, but may be made from other material such as carbon fiber resin, glass fiber resin, leather, canvas, and rope. 
     The tank protector  90  is a member that protects the tank  60  from external force. External force is applied when, for example, the vehicle  100  collides. The tank protector  90  is provided on an outer side of the tank  60 , and is also fixed to outer sides of the bands  80 . The tank protector  90  may be fixed to inner sides of the bands  80 , or may be fixed to the inner sides of the bands  80  and the outer sides of the bands  80 . In the latter case, two of the tank protectors  90  are used. 
     From a perspective of protecting the tank  60 , in view of the vehicle  100  from the rear side (the −X axis direction side) in parallel to the X axis direction, it is preferred that a ratio of a range of the tank  60  that overlaps the tank protector  90  is at least 50% of the entire tank  60 . It is more preferred when the ratio is 60%, and the ratio of 70% is even more preferred. Meanwhile, from a perspective of weight reduction of the tank protector  90 , it is preferred that the ratio of the range of the tank  60  that overlaps the tank protector  90  is 90% or lower of the entire tank  60 , and the ratio of 80% or lower is more preferred. In the embodiment, in view of the vehicle  100  from the rear side (the −X axis direction side) in parallel to the X axis direction, the ratio of the range of the tank  60  that overlaps the tank protector  90  is 70% or higher but not exceeding 80% of the entire tank  60 . 
     From the perspective of protecting the tank  60  from external force, it is preferred that shear strength of the tank protector  90  is greater than that of the bands  80 . In the specification, shear strength means a load required to penetrate a member using a punch with the same size. Shear strength is proportional to a thickness of a member. In the embodiment, the tank protector  90  is made from metal that is the same material as that of the band  80 . Since the tank protector  90  is thicker than the band  80 , shear strength of the tank protector  90  is greater than that of the band  80 . The material of the tank protector  90  is not limited to metal, and may be other material such as carbon fiber resin and polycarbonate. 
     As shown in  FIG.  4   , in the embodiment, the tank protector  90  is fixed to each of the bands  80  at two locations by bolts  92 ,  93 . A fixing method for the tank protector  90  is not limited to bolts but may be, for example, welding between the tank protector  90  and the bands  80 . In the embodiment, the tank protector  90  is fixed to portions of the bands  80  that are not the end portions in the front-rear direction (the X axis direction). In the embodiment, from a viewpoint of restraining the bolt  92  provided on the upper side from coming into contact with the underbody  20 , the portion of the tank protector  90  in which the bolt  92  is provided is thinner than the rest of the tank protector  90 . However, the disclosure is not limited to this. For example, in the portion of the tank protector  90  in which the bolt  92  is provided may have the same thickness as that of the rest of the tank protector  90 . 
     As shown in  FIG.  3   , in the embodiment, the tank protector  90  is made out of three members. Specifically, tank protector  90  includes a center member  95  disposed in the center, and two end portion members  96  provided on both end sides of the center member  95 , respectively. The center member  95  is a member provided on an outer side of the cylinder portion  11  of the tank  60 . The end portion members  96  are members provided on outer sides of the dome portions  12  of the tank  60 , respectively. In the embodiment, the center member  95  and each of the end portion members  96  are joined to each other by welding. Further, an overlapping portion of the center member  95  and each of the end portion members  96  has a width required for welding (for example, between about 1 cm and 2 cm), and the center member  95  does not reach the both ends of the tank protector  90 . By doing so, rigidity of a connecting portion between each of the end portion members  96  and the center member  95  is enhanced. Thus, it is possible to restrain flapping elastic deformation of the end portion members  96  caused by vibration of the vehicle  100  in the front-rear direction (the X axis direction). The end portion members  96  and the center member  95  may be welded to each other through their end surfaces. 
     In the embodiment, a thickness of each of the end portion members  96  is larger than that of the center member  95 . The “thickness” means a distance between a pair of flat plates that sandwiches a flat portion of a member. Thus, the dome portions  12  having relatively low strength are protected selectively by the end portion members  96 , respectively. At the same time, by reducing the thickness of the center member  95  so as to be smaller than those of the end portion members  96 , the weight of the tank protector  90  is reduced. The disclosure is not limited to this, and the center member  95  may have the same thickness as those of the end portion members  96 , or the center member  95  may be thicker than the end portion members  96 . The tank protector  90  may be made of, for example, a single member instead of the three members. 
     In the embodiment, the tank protector  90  is provided on the rear side (the −X axis direction side) of the tank  60 . By doing so, the tank protector  90  is able to protect the tank  60  from external force from the rear side of the vehicle  100 . The disclosure is not limited to this, and the tank protector  90  may be provided on the front side (the +X axis direction side) of the tank  60 . As the tank protector  90  is provided on the front side of a portion of the tank  60  where the external force can be applied, the tank protector  90  is able to protect the tank  60  efficiently. 
     In the embodiment, when the tank protector  90  is seen in the width direction of the vehicle  100  (the Z axis direction), the tank protector  90  is bent along the surface of the tank  60 . Thus, the tank protector  90  is restrained from being bent in the width direction (the Z axis direction). 
     Also, as shown in  FIG.  3   , in the embodiment, an upper end (an end on the +Y axis direction side) of the center member  95  of the tank protector  90  is at the same height as an upper end of each of the end portion members  96 . As shown in  FIG.  4   , the upper end of the tank protector  90  is located above a surface P 1  of the tank  60 . The surface P 1  is located above a horizontal plane S 1  at an angle of 45° from a central axis CX. The horizontal plane S 1  passes the central axis CX of the tank  60 . Thus, even when the tank  60  receives external force from the rear side (the −X axis direction side) to the front side (the +X axis direction side) of the vehicle  100  above the tank protector  90 , over a half of the external force is warded off along the surface of the tank  60 . 
     Further, as shown in  FIG.  3   , in the embodiment, a lower end of each of the end portion members  96  of the tank protector  90  is positioned so as to be lower than a lower end of the center member  95  of the tank protector  90 . Thus, it is possible to enhance protection of the dome portions  12  that have less strength than the cylinder portion  11  in the tank  60 . 
     As shown in  FIG.  5   , in the embodiment, the lower end of each of the end portion members  96  of the tank protector  90  is located below a surface P 3  of the tank. The surface P 3  is located below the horizontal plane S 1  at an angle of 45° from the central axis CX. The horizontal plane S 1  passes the central axis CX of the tank  60 . Thus, even when the tank  60  receives external force from the rear side (the −X axis direction side) to the front side (the +X axis direction side) of the vehicle  100  below the tank protector  90 , over a half of the external force is warded off along the surface of the tank  60 . 
     As described above, in the mounting structure of the tank  60  according to the embodiment, the tank protector  90  is fixed to the bands  80 . Therefore, when there is variation in size of the tank  60 , or the tank  60  contracts, the bands  80  and the tank protector  90  synchronize with the tank  60 , and it is thus possible to restrain expansion of the gap between the tank  60  and the tank protector  90 . As a result, the gap is kept minimized, and it is thus possible to restrain a foreign object such as a large stone from trapped in the gap. In particular, in a case of a movable body such as a vehicle, a foreign object such as a large stone can enter the movable body while it is moving. However, with the mounting structure for the tank  60  according to the embodiment, it is possible to restrain such a foreign matter from being trapped in the gap between the tank  60  and the tank protector  90 . Further, as a result of restraining expansion of the gap between the tank  60  and the tank protector  90 , noise that can be generated by the gap is addressed easily. 
     B. Other Embodiments 
     In the foregoing embodiment, the frames  70  are provided on the lower side (the −X axis direction side) of the tank  60 , and the bands  80  are provided on the upper side (the +X axis direction side) of the tank  60 . However, the disclosure is not limited to this. For example, the frames  70  may be provided on the upper side (the +X axis direction side) of the tank  60 , and the bands  80  may be provided on the lower side (the −X axis direction side) of the tank  60 . 
     In the foregoing embodiment, as the mounting structure of the tank  60 , the vehicle  100  on which the tank  60  is mounted is described as an example. However, the disclosure is not limited to this. For example, the disclosure may be used in a movable body other than a vehicle, the movable body using the mounting structure of the tank  60  according to the embodiment. Further, the mounting structure of the tank  60  may be used in a fixed device. By providing the tank protector  90  on the outer side of a portion of the tank  60  where an impact is likely to be applied from outside, it is possible to protect the tank  60  effectively. 
     In the above embodiment, the spring  84  allows the band  80  to deform in accordance with expansion or contraction of the tank  60 . However, the disclosure is not limited to this, and other elastic body such as rubber may be used instead of the spring  84 , and the band  80  itself may be made from an elastic material such as resin. 
     In the foregoing embodiment, each of the bands  80  and the center member  95  of the tank protector  90  are fixed to each other by the bolts  92 ,  93 . However, the disclosure is not limited to this, and the bands  80  and the end portion members  96  of the tank protector  90  may be fixed by bolts, respectively. Thus, since the end portion members  96  are thicker than the center member  95 , the tank protector  90  is fixed to the bands  80  more reliably. 
     The disclosure is not limited to the embodiments, and can be carried out in various configurations without departing from the gist of the disclosure. For example, the technical characteristics in the embodiments corresponding to the technical characteristics in the respective aspects described in Summary may be replaced or combined as appropriate in order to achieve a part of or all of the effects. Unless the technical characteristics are described as essential in the specification, such technical characteristics may be deleted as appropriate.