Vehicle Structure

Abstract

To provide a vehicle body structure advantageous in preventing a fuel tank from interfering with peripheral vehicle-mounted components, in the event of side collision.SOLUTION: A fragile portion 34 is provided in a part of a third cross member 16 positioned on the other side in a vehicle width direction from a front end part 24 of a fuel tank 22, and a reinforcing portion 32 is provided in a portion of a third cross member 16 positioned directly below the front end part 24 or on one side in the vehicle width direction from the front end part 24. By virtue of this, since the third cross member 16 breaks at the fragile portion 34 in the event of side collision, a portion directly below the front end part 24 or on one side in a vehicle width direction (outside in the vehicle width direction) from the front end part 24 is prevented from relatively moving toward one side with respect to the front end part 24. Accordingly, falling of the front end part 24 from a first mounting member 36 can be prevented, thus adding the advantage of preventing the fuel tank 22 from interfering with peripheral vehicle-mounted components.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle structure. [Background technology]

[0002] A vehicle structure has been proposed in which a fuel tank is positioned on one side of the vehicle width between the pair of side members for a vehicle that has a pair of side members extending in the fore-and-aft direction of the vehicle and multiple cross members extending in the vehicle width direction and connecting the pair of side members. In this vehicle structure, the cross member has an extension portion located in the center of the vehicle width direction, and a pair of widening portions that are joined to both ends of the extension portion by separate members and have a cross-section that increases in size as it extends in the vehicle width direction and is joined to the side members (see Patent Document 1). Therefore, during a side collision, stress is concentrated at the joint between the extension portion and the widened portion, making the cross member prone to breakage at this joint. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2011 / 101906 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, in order to ensure the capacity of the fuel tank, it is conceivable to have a portion of the front end of the fuel tank protrude forward of the vehicle and attach the front end of the fuel tank to the cross member with the front end of the fuel tank placed on the cross member. Here, if the front end of the fuel tank is completely fixed to the cross member, for example by a bolt, when the cross member breaks as described above during a side collision and the part of the cross member on the opposite side of the vehicle width direction from the breaking point of the cross member moves toward the collision object, the front end of the fuel tank attached to the above-mentioned cross member also moves in the same direction following the movement of the above-mentioned cross member. However, if the front end of the fuel tank is not completely fixed to the cross member due to factors such as the material of the fuel tank and the manufacturing costs of the mounting structure for the fuel tank, and the front end of the fuel tank is mounted to the cross member by, for example, a strip-shaped mounting member, the cross member will break during a side collision and the cross member will move toward the object of impact, but the front end of the fuel tank, which is mounted to the cross member by the mounting member, will tend to remain in place without moving with the movement of the cross member. This results in relative movement between the cross member and the front end of the fuel tank in the vehicle width direction. This could cause the front end of the fuel tank to come loose from the mounting member and fall off the cross member, raising concerns that the fuel tank could interfere with surrounding vehicle components. The present invention has been made in consideration of the above circumstances, and has an object to provide a vehicle body structure that is advantageous in suppressing interference between a fuel tank and surrounding vehicle mounted components during a side collision. [Means for solving the problem]

[0005] In order to achieve the above-mentioned objective, one embodiment of the present invention comprises a pair of side members extending in the fore-and-aft direction of the vehicle, a fuel tank arranged on one side of the vehicle width between the pair of side members, a cross member extending in the vehicle width direction to connect the pair of side members and placing a front end of the fuel tank on one side of the vehicle width, and a mounting member for attaching the front end to the cross member, wherein the cross member has a weak portion on the other side of the vehicle width of the front end, and a reinforcing portion is provided in a portion of the cross member located directly below the front end or on one side of the vehicle width of the front end. One embodiment of the present invention comprises a pair of side members extending in the fore-and-aft direction of the vehicle, a fuel tank arranged on one side of the vehicle width between the pair of side members, a cross member extending in the vehicle width direction to connect the pair of side members and for placing a front end of the fuel tank on one side of the vehicle width, and a mounting member for attaching the front end to the cross member, wherein the cross member is made up of two members: a bottom plate portion that forms the bottom along the entire length of the cross member in the vehicle width direction, and a main body plate portion that is arranged above the bottom plate portion, that forms the remaining entire length of the cross member in the vehicle width direction excluding the bottom, and has widening portions whose both vehicle width end portions are widened toward the outside, and is characterized in that a weak portion is provided in a portion of the cross member on the other side of the vehicle width direction than the front end. In one embodiment of the present invention, the weakened portion is configured to include a recess, a hole, or a notch provided in the cross member. One embodiment of the present invention is characterized in that the cross member has an extension portion extending in the vehicle width direction, and a widening portion made of a separate member from the extension portion, joined to both ends of the extension portion in the vehicle width direction, and widened toward the outside, and the reinforcing portion is provided across the extension portion and the widening portion at the boundary between the extension portion and the widening portion on one side in the vehicle width direction. One embodiment of the present invention is characterized in that the weak portion is provided on the upper surface of the extension portion, and the widening portion is such that the lower surface of the cross member extends in a straight line in the vehicle width direction, and the upper surface of the cross member widens upward. One embodiment of the present invention is characterized in that the extension portion has a pair of brackets supporting a propeller shaft on the other side of the vehicle width direction from the front end portion, and the weak portion is provided between the pair of brackets. In one embodiment of the present invention, the front end portion is disposed adjacent to the pair of brackets on one side in the vehicle width direction. One embodiment of the present invention is characterized in that the front end portion is formed by a portion of the front end of the fuel tank protruding forward of the vehicle, and the mounting member comprises a belt-shaped member that fastens the front end portion to the cross member. One embodiment of the present invention is characterized in that one longitudinal end of the belt-shaped member is attached to one of the pair of brackets on one side in the vehicle width direction, and the other end is attached to the widening portion. Effect of the Invention

[0006] According to one embodiment of the present invention, a weak portion is provided at a portion of the cross member located on the other side of the front end of the fuel tank in the vehicle width direction, and a reinforcement portion is provided at a portion of the cross member located directly below the front end or on one side of the front end in the vehicle width direction. Therefore, in the event of a side collision, the cross member breaks at the weak portion, which prevents the portion directly below the front end or on one side of the front end from moving relatively to one side in the vehicle width direction with respect to the front end, thereby preventing the front end from falling off the mounting member, which is advantageous in preventing the fuel tank from interfering with surrounding vehicle-mounted components. According to one embodiment of the present invention, the cross member is composed of two members, a bottom plate portion and a main plate portion, and a weak portion is provided at a portion of the cross member located on the other side of the front end of the fuel tank in the vehicle width direction. Therefore, in the event of a side collision, the cross member breaks at the weak portion, which prevents the portion directly below the front end or on one side of the front end in the vehicle width direction from moving relatively to one side in the vehicle width direction with respect to the front end, thereby preventing the front end from falling off the mounting member, which is advantageous in preventing the fuel tank from interfering with surrounding vehicle-mounted components. According to one embodiment of the present invention, the weakened portion is configured to include a recess, a hole, or a notch provided in the cross member, which is advantageous in terms of easily forming the weakened portion. According to one embodiment of the present invention, the boundary between the extension portion of the cross member and the widened portion on one side in the vehicle width direction is reinforced by the reinforcing portion, which is advantageous in preventing the cross member from breaking at the boundary and in promoting bending of the cross member at the weak portion, and is more advantageous in preventing the fuel tank from interfering with surrounding vehicle mounted components. According to one embodiment of the present invention, the load applied to the cross member during a side collision is likely to be applied downward to the weak portion, which is more advantageous in promoting downward bending of the cross member at the weak portion and is even more advantageous in preventing interference of the fuel tank with surrounding vehicle mounted components. According to one embodiment of the present invention, when the cross member bends downward at a weak portion during a side collision, the bracket is interposed between the front end and the propeller shaft, which is advantageous in preventing the front end from interfering with the propeller shaft. According to one embodiment of the present invention, when the cross member bends downward at a weak portion during a side collision, the bracket can be more securely interposed between the front end and the propeller shaft, which is more advantageous in preventing the front end from interfering with the propeller shaft. According to one embodiment of the present invention, the front end is formed by a portion of the front end of the fuel tank protruding forward of the vehicle, and the mounting member is constructed from a strip-shaped member, which is advantageous in supporting the front end with a simple structure. According to one embodiment of the present invention, the front end can be attached with a band-shaped member using a bracket, which eliminates the need for additional dedicated mounting fixtures, which is advantageous in reducing the number of parts. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a configuration of a vehicle to which a vehicle structure according to a first embodiment is applied. [Diagram 2] FIG. 2 is a view taken along line AA in FIG. [Diagram 3] FIG. 3 is a view taken along the arrow B in FIG. 2. [Figure 4] 2A is a view taken along line CC in FIG. 1, and FIG. 2B is a diagram showing the cross-sectional strength of the third cross member shown in FIG. [Diagram 5] 4 is an explanatory view showing a state of a third cross member and a fuel tank after a side collision in the vehicle structure according to the first embodiment, as viewed from the front of the vehicle. FIG. [Figure 6]13(A) and 13(B) are perspective views showing modified examples of weakened portions provided in the third cross member. [Figure 7] FIG. 5 is a front view of a third cross member in a vehicle structure according to a second embodiment, corresponding to FIG. 4(A). [Figure 8] 13 is an explanatory view showing a state of a third cross member and a fuel tank after a side collision in a vehicle structure according to a second embodiment, as viewed from the front of the vehicle. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle structure according to an embodiment of the present invention will now be described with reference to the drawings. In the following drawings, the symbol FR indicates the front of the vehicle, the symbol UP indicates the upper side of the vehicle, and the symbol HL indicates the vehicle width direction. As shown in FIG. 1, in the embodiment of the present invention, a vehicle 10 is a frame vehicle 10 in which a cab body (not shown) including a passenger compartment in which passengers sit is supported by a chassis frame 12. The frame vehicle 10 may be a pickup truck type vehicle 10 in which a cab body and a cargo box are supported by a chassis frame 12. In this embodiment, the frame vehicle 10 has an engine, transmission, and front wheels (not shown) arranged at the front of the vehicle, and a differential gear (not shown) and rear wheels (which serve as drive wheels) arranged at the rear of the vehicle.

[0009] The chassis frame 12 is configured to include a pair of side members 14 and a plurality of cross members. The pair of side members 14 extend in the front-rear direction of the vehicle and are spaced apart from each other in the vehicle width direction. The pair of side members 14 support the cab body from below, or support the cab body and a cargo box from below.

[0010] The multiple cross members extend in the vehicle width direction at multiple locations spaced apart in the vehicle front-rear direction and connect a pair of side members 14 together. In this embodiment, the multiple cross members include five cross members: a first, second, third, fourth and fifth cross members, which are arranged in that order from front to rear. In FIG. 1, of the five cross members, a third cross member 16 and a fourth cross member 18 are shown. The third cross member 16 is connected to the longitudinal center of the pair of side members 14, and the fourth cross member 18 is connected to the pair of side members 14 at a location spaced from the third cross member 16 toward the rear of the vehicle.

[0011] A propeller shaft 20 and a fuel tank 22 are attached to the chassis frame 12. The propeller shaft 20 connects the transmission and the differential gear, and transmits the driving force of the engine to the rear wheels via the differential gear. In this embodiment, the propeller shaft 20 extends in the front-rear direction of the vehicle so as to pass above the third cross member 16 and below the fourth cross member 18.

[0012] A front end 24 of the fuel tank 22 is placed on one side of the third cross member 16 in the vehicle width direction. As shown in Figure 4 (A), the third cross member 16 has an extension portion 26 and a pair of widening portions 28 that are made of a separate member from the extension portion 26 and are joined to both ends of the extension portion 26 in the vehicle width direction. Extension portion 26 is composed of two members, an upper extension portion 2602 and a lower extension portion 2604 joined to the lower portion of upper extension portion 2602, and is formed with a uniform cross-sectional shape extending in the vehicle width direction. In addition, in FIG. 1, reference numeral 2610 denotes the ridge line of the boundary between the upper surface 2602A of the upper extension portion 2602 and the front surface. As shown in FIG. 4(A), a pair of brackets 30 are provided on an upper surface 2602A of an upper extending portion 2602 located in the longitudinal center of the third cross member 16, spaced apart in the vehicle width direction. As shown in FIG. 1, a middle portion of the propeller shaft 20 in the longitudinal direction is supported above the center portion of the third cross member 16 in the longitudinal direction via a pair of brackets 30.

[0013] As shown in Figs. 1, 3 and 4(A), the pair of widened portions 28 have a cross-sectional shape that gradually widens toward the outside in the vehicle width direction. In detail, the widened portion 28 is such that the lower surface of the third cross member 16 extends linearly in the vehicle width direction, and the upper surface, front surface, and rear surface of the third cross member 16 widen in the fore-and-aft direction of the vehicle and upward as they reach the outside in the vehicle width direction. As shown in FIG. 4(A), the widened portion 28 is made up of two members: an upper widened portion 2802 and a lower widened portion 2804 joined to the lower portion of the upper widened portion 2802. Therefore, the third cross member 16 is composed of six members: an upper extending portion 2602, a lower extending portion 2604, a pair of upper widened portions 2802, and a pair of lower widened portions 2804. In addition, in FIG. 1, reference numeral 2810 denotes the ridge line of the boundary between the top surface and the front surface of the upper widened portion 2802. The inner surface of the inner end of the upper widened portion 2802 on the inner side in the vehicle width direction is overlapped and joined to the outer surfaces of both ends of the upper extending portion 2602. The inner surface of the end portion on the inner side in the vehicle width direction of the lower widening portion 2804 is overlapped and joined to the outer surfaces of both ends of the lower extending portion 2604. The outer end of the upper widened portion 2802 in the vehicle width direction and the outer end of the lower widened portion 2804 in the vehicle width direction are joined to the inner surface of the side member 14 in the vehicle width direction.

[0014] As shown in FIG. 1, at a boundary portion 29 between the extending portion and the pair of widened portions , a reinforcing portion 32 is provided across the extending portion and the widened portions . In detail, the reinforcing portion 32 is provided across both ends of the upper extending portion 2602 and the ends of the pair of upper widened portions 2802 . The reinforcing portion 32 is configured with a reinforcement 32A made of a metal plate bent into an L-shaped cross section. The reinforcement 32A has a front plate facing forward, an upper plate extending rearward from the upper edge of the front plate and facing upward, and a ridge 3210 formed between the front plate and the upper plate. The reinforcement 32A has its front plate and upper plate overlapped and joined to the upper surface 2602A, front surface of the upper extension portion 2602 and the upper surface and front surface of the upper widening portion 2802, with its ridge 3210 aligned with the ridge 2610 of the upper extension portion 2602 of the third cross member 16 and the ridge 2810 of a pair of upper widening portions 2802.

[0015] As shown in Figs. 1 and 4(A), the third cross member 16 is provided with a weakened portion 34 in the center in the longitudinal direction. The weak portion 34 is a portion that is deformed first compared to other portions when a load acts on the third cross member 16 during a side collision. In the present embodiment, the weakened portion 34 is provided between the pair of brackets 30 of the third cross member 16 . The fragile portion 34 is constituted by a recess 34A provided on the upper surface 2602A of the upper extending portion 2602 in the longitudinal center, and the recess 34A is provided over the entire length of the upper surface 2602A of the upper extending portion 2602 in the vehicle front-rear direction.

[0016] As shown in FIG. 1, fuel tank 22 is made of synthetic resin or sheet metal, has an elongated shape, and is disposed on one side in the vehicle width direction between a pair of side members 14 with its longitudinal direction aligned with the vehicle front-rear direction, and more specifically, is provided between propeller shaft 20 and side member 14 on one side in the vehicle width direction. In other words, the fuel tank 22 is adjacent to the propeller shaft 20 on one side of the propeller shaft 20 in the vehicle width direction, and extends along the propeller shaft 20 in the front-rear direction of the vehicle. In the present embodiment, the fuel tank 22 extends from directly above the third cross member 16 to below the fourth cross member 18 to the rear of the fourth cross member 18.

[0017] As shown in Figures 1 to 3, the fuel tank 22 comprises a tank body 23 and a front end portion 24 formed by a portion of the front end of the tank body 23 protruding forward of the vehicle, and is attached to the chassis frame 12 via a first mounting member 36, a second mounting member 38, and a third mounting member 40, which will be described later.

[0018] The front end 24 is formed with a cross-sectional shape that is smaller than the cross-sectional shape of the tank body 23 when broken in a plane perpendicular to the extension direction of the fuel tank 22, and providing such a front end 24 is advantageous in ensuring a larger capacity of the fuel tank 22. The front end 24 is placed on one side of the upper surface 2602A of the extension portion 26 of the third cross member 16 in the vehicle width direction, and is positioned adjacent to the bracket 30 on one side of the pair of brackets 30 in the vehicle width direction. The other end of the front end 24 in the vehicle width direction is located at a position displaced to one side in the vehicle width direction from the center of the upper extension portion 2602 in the vehicle width direction, and therefore the weak portion 34 is located on the other side in the vehicle width direction from the front end portion 24. The end portion on one side of the front end portion 24 in the vehicle width direction is located at the end portion on one side of the upper surface 2602A of the extension portion 26 in the vehicle width direction, and therefore the reinforcement portion 32 is located directly below the front end portion 24 or to one side of the front end portion 24 in the vehicle width direction. As shown in FIGS. 1 and 2, the front end portion 24 is attached to the third cross member 16 via a first mounting member 36. The first mounting member 36 consists of a strip-shaped member 36A formed from a metal material, one longitudinal end of which is attached to a bracket 30 on one side of the vehicle width direction, and the other end is attached to the widening portion 28 on one side of the vehicle width direction of the third cross member 16. The middle portion of the belt-shaped member 36A presses against the upper surface of the front end portion 24 from above, clamping the front end portion 24 to the upper surface 2602A of the upper extension portion 2602, and supporting the front end portion 24 so that it cannot move in the vertical and widthwise directions. Furthermore, the front end 24 is not completely fixed to the third cross member 16 by, for example, bolts, but is attached to the third cross member 16 via the first mounting member 36, taking into consideration the material of the fuel tank 22 and the manufacturing costs of the first mounting member 36.

[0019] As shown in FIGS. 2 and 3, the lower surface of the fuel tank 22 except for the rear portion is covered with a tank tray 42 made of a metal material or a synthetic resin material. As shown in FIG. 3, tank tray 42 is attached at multiple locations 42A, 42B, 42C in the middle portion thereof to the underside of fuel tank 22 by clips or bolts (not shown). A groove 4202 is formed in the lower surface of the front part of the tank tray 42 in a direction intersecting with the front-rear direction of the vehicle, and the second mounting member 38 is inserted into this groove 4202 and disposed therein. The second mounting member 38 is composed of a strip-shaped member 38A formed of a metal material, with one longitudinal end of the strip-shaped member 38A attached to the underside of the third cross member 16 and the other end of the strip-shaped member 38A attached to the underside of the side member 14 on one side in the vehicle width direction, and the middle portion of the strip-shaped member 38A supporting the fuel tank 22 from below via the tank tray 42. Therefore, the fuel tank 22 is supported via the tank tray 42 so as not to be movable in the vehicle front-rear direction, the vehicle width direction, and downward.

[0020] As shown in FIGS. 1 to 3, the rear portion of the fuel tank 22 is located below the fourth cross member 18 and protrudes rearward beyond the fourth cross member 18. As shown in FIGS. 2 and 3, a third mounting member 40 is disposed on the lower surface of the rear portion of the fuel tank 22. The third mounting member 40 is composed of a strip-shaped member 40A formed of a metal material, one longitudinal end of the strip-shaped member 40A is attached to the underside of the fourth cross member 18 on one side of the rear of the fuel tank 22 in the vehicle width direction, the longitudinal middle portion of the strip-shaped member 40A fastens the underside of the rear of the fuel tank 22 to the underside of the fourth cross member 18, and the other longitudinal end of the strip-shaped member 40A is attached to the underside of the fourth cross member 18 on the other side of the fuel tank 22 in the vehicle width direction. Therefore, the rear portion of the fuel tank 22 is fastened by the fourth cross member 18 and the belt-shaped member 40A, and is supported so as not to move in the vertical direction or in the vehicle width direction.

[0021] Next, the effects will be described. As shown in FIGS. 4(A) and 4(B), the cross-sectional strength of the third cross member 16 is minimum at the weakened portion 34. The third cross member 16 has a constant sectional strength higher than that of the weak portion 34 in the portion of the extension portion 26 excluding the weak portion 34 . On the other hand, the boundary portion 29 between the extension portion 26 and the widened portion 28 of the third cross member 16 is the joint between the extension portion 26 and the widened portion 28, and is a point where the cross-sectional strength is locally reduced.In addition, since the upper surface of the widened portion 28 widens upward as it approaches the outside in the vehicle width direction, the boundary portion 29 is a point where stress is concentrated during a side collision and is likely to break downward. In this embodiment, therefore, a reinforcing portion 32 is provided at boundary portion 29 where extension portion 26 and widened portion 28 are joined, thereby ensuring that the sectional strength of boundary portion 29 is higher than the sectional strength of extension portion 26 . The cross-sectional strength of the third cross member 16 initially decreases in the areas where the reinforcing portions 32 are not positioned as it moves from the boundary portion 29 toward the outside in the vehicle width direction, but since the cross-sectional area of ​​the widened portion 28 is wider than the cross-sectional area of ​​the extended portion 26, the cross-sectional strength is greater than the cross-sectional strength of the extended portion 26. The cross sectional strength of the third cross member 16 gradually increases from the point where the cross sectional strength decreases toward the outer side in the vehicle width direction, and reaches a maximum at the outer end of the widened portion 28 in the vehicle width direction. Therefore, by providing the reinforcing portion 32, the cross-sectional strength is ensured at the boundary portion 29 between the extension portion 26 and the widening portion 28 of the third cross member 16, and the boundary portion 29 between the extension portion 26 and the widening portion 28 of the third cross member 16 is prevented from bending downward in the event of a side collision.

[0022] This prevents the third cross member 16 from bending downward directly below the front end 24 of the fuel tank 22 or to one side of the vehicle width direction (the outer side in the vehicle width direction) of the front end 24 during a side collision, as shown in Figure 5, while promoting the third cross member 16 to bend downward at the weak portion 34. Therefore, during a side collision, a portion of third cross member 16 directly below front end 24 of fuel tank 22 or on one side in the vehicle width direction (outer side in the vehicle width direction) of front end 24 bends downward. This makes it possible to prevent the portion of the third cross member 16 directly below the front end portion 24 or the portion of the third cross member 16 on one side in the vehicle width direction (outside in the vehicle width direction) of the front end portion 24 from moving to one side in the vehicle width direction (outside in the vehicle width direction). In other words, the portion of the first mounting member 36 that is attached to one side in the vehicle width direction can be prevented from moving to that side in the vehicle width direction (outside in the vehicle width direction).

[0023] That is, according to this embodiment, a weak portion 34 is provided in a portion of the third cross member 16 located on the other side of the vehicle width direction than the front end 24 of the fuel tank 22, and a reinforcing portion 32 is provided in a portion of the third cross member 16 located directly below the front end 24 or on one side of the front end 24 in the vehicle width direction. Therefore, in the event of a side collision, the third cross member 16 breaks at the weak portion 34, thereby preventing the portion directly below the front end portion 24 or to one side in the vehicle width direction (on the outer side in the vehicle width direction) of the front end portion 24 from moving relatively to one side in the vehicle width direction with respect to the front end portion 24. Therefore, it is possible to prevent the front end portion 24 from falling off the first mounting member 36, which is advantageous in preventing the fuel tank 22 from interfering with surrounding vehicle mounted components, such as the propeller shaft 20.

[0024] Furthermore, according to this embodiment, the weakened portion 34 is formed by providing the recess 34A in the third cross member 16, which is advantageous in that the weakened portion 34 can be formed easily. In addition, instead of the recess 34A, the weak portion 34 may be formed by a hole 34B provided in the upper surface 2602A of the extension portion 26 of the third cross member 16, as shown in Figure 6 (A), or by a recess 34C provided on the front and rear ridges of the upper surface 2602A of the extension portion 26 of the third cross member 16, as shown in Figure 6 (B), or by a notch provided in the upper surface 2602A of the extension portion 26 of the third cross member 16, and forming the weak portion 34 in this manner is advantageous in terms of easily forming the weak portion 34.

[0025] Furthermore, according to this embodiment, the boundary portion 29 at which the extension portion 26 and the widened portion 28 of the third cross member 16 are joined is reinforced by the reinforcing portion 32 . This is advantageous in preventing the third cross member 16 from breaking at the boundary portion 29 and in promoting the third cross member 16 to bend downward at the weak portion 34, and is more advantageous in preventing the fuel tank 22 from interfering with surrounding vehicle-mounted components.

[0026] Furthermore, according to this embodiment, recesses 34A, 34C or holes 34B are formed in upper surface 2602A of extension portion 26, and widened portion 28 has a lower surface that extends linearly in the vehicle width direction and an upper surface that widens upward. Therefore, during a side collision, the load applied to the third cross member 16 is more likely to be applied downward to the weak portion 34, which is more advantageous in promoting downward bending at the weak portion 34 and is even more advantageous in preventing the fuel tank 22 from interfering with surrounding vehicle mounted components.

[0027] In addition, according to this embodiment, the extension portion 26 is provided on the other side of the vehicle width direction from the front end portion 24, and has a pair of brackets 30 supporting the propeller shaft 20, and the weak portion 34 is provided between the pair of brackets 30. Therefore, when the third cross member 16 bends downward at the weak portion 34 during a side collision, the bracket 30 is interposed between the front end portion 24 and the propeller shaft 20, which is advantageous in preventing the front end portion 24 from interfering with the propeller shaft 20.

[0028] Further, according to this embodiment, the front end portion 24 is disposed adjacent to a pair of brackets 30 on one side in the vehicle width direction. Therefore, when the third cross member 16 bends downward at the weak portion 34 during a side collision, the bracket 30 can be more securely interposed between the front end portion 24 and the propeller shaft 20, which is more advantageous in preventing the front end portion 24 from interfering with the propeller shaft 20.

[0029] Furthermore, according to this embodiment, front end 24 is formed by a portion of the front end of fuel tank 22 protruding forward of the vehicle, and first mounting member 36 is composed of strip-shaped member 36A, which is advantageous in supporting front end 24 with a simple structure.

[0030] In addition, according to this embodiment, one longitudinal end of the belt-shaped member 36A is attached to the bracket 30 on one side of the pair of brackets 30 in the vehicle width direction, and the other longitudinal end of the belt-shaped member 36A is attached to the widening portion 28. Therefore, the front end 24 can be attached with the band-shaped member 36A by utilizing the bracket 30, which eliminates the need for additional dedicated mounting fixtures, and is advantageous in terms of reducing the number of parts.

[0031] (Second embodiment) Next, a second embodiment will be described with reference to FIGS. In the following embodiment, the same parts and members as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and the description will focus on the differences. In the first embodiment, the third cross member 16 is composed of six members, whereas in the second embodiment, the third cross member 16 is composed of two members, and differs from the first embodiment in that the reinforcing portion 32 provided in the first embodiment is omitted.

[0032] As shown in FIG. 7, the third cross member 16 has an extending portion 44 extending in the vehicle width direction, and a pair of widened portions 46 connected to both ends of the extending portion 44 in the vehicle width direction. The extension portion 44 is formed with a uniform cross-sectional shape extending in the vehicle width direction. The pair of widened portions 46 have a cross-sectional shape that gradually widens toward the outside in the vehicle width direction. In detail, the widening portion 46 is such that the lower surface of the third cross member 16 extends linearly in the vehicle width direction, and the upper surface, front surface, and rear surface of the third cross member 16 widen in the fore-and-aft direction of the vehicle and upward as they reach the outside in the vehicle width direction.

[0033] The third cross member 16 is composed of two members, a bottom plate portion 48 and a main body plate portion 50 that is disposed above the bottom plate portion 48 and joined to the bottom plate portion 48, and has a closed cross-sectional shape. The bottom plate portion 48 forms the bottom portion over the entire length of the third cross member 16 in the vehicle width direction, and comprises a bottom plate facing downward, a front plate that rises upward from the front edge of the bottom plate, and a rear plate that rises upward from the rear edge of the bottom plate. The main body plate portion 50 is positioned above the bottom plate portion 48 and constitutes the entire widthwise length of the remaining third cross member 16 excluding the bottom portion, and is equipped with an upper plate facing upward, a front plate that rises downward from the front edge of the upper plate, and a rear plate that rises downward from the rear edge of the upper plate. In other words, the main body plate portion 50 has widened portions 46 whose widths increase toward the outside at both ends in the vehicle width direction. The front and rear plates of the main body plate portion 50 are overlapped and joined from the outside of the front and rear plates of the bottom plate portion 48 to form the third cross member 16.

[0034] A pair of brackets 30 are provided at intervals in the vehicle width direction on the upper surface of the longitudinal center portion of the main body plate portion 50 of the third cross member 16 (in other words, on the upper surface 4402 of the longitudinal center portion of the extension portion 44), and the longitudinal middle portion of the propeller shaft 20 is supported above the longitudinal center portion of the main body plate portion 50 of the third cross member 16 via the pair of brackets 30. The third cross member 16 is provided with a weakened portion 52 in the longitudinal center thereof. The weakened portion 52 is provided on the upper surface of the main body plate portion 50 between the pair of brackets 30 . The fragile portion 52 is composed of a recess 52A provided on the upper surface of the longitudinal center portion of the main body plate portion 50 (in other words, on the upper surface 4402 of the longitudinal center portion of the extension portion 44), and the recess 52A is provided over the entire length of the upper surface of the main body plate portion 50 in the fore-and-aft direction of the vehicle. Also, as in the first embodiment, instead of the recess 52A, the weak portion 52 may be formed by a hole provided in the upper surface of the main body plate portion 50 of the third cross member 16, or a recess provided on the front and rear ridges of the upper surface of the main body plate portion 50 of the third cross member 16, or a notch provided in the upper surface of the main body plate portion 50 of the third cross member 16.

[0035] The structure and arrangement of the fuel tank 22 are similar to those of the first embodiment, and the fuel tank 22 is arranged adjacent to the propeller shaft 20 on one side of the propeller shaft 20 in the vehicle width direction, via the first, second, and third mounting members 40 and the tank tray 42, and extends in the fore-and-aft direction of the vehicle along the propeller shaft 20. The front end 24 of the fuel tank 22 is placed on one side of the upper surface 4402 of the extension portion 44 of the third cross member 16 in the vehicle width direction, and is positioned adjacent to the bracket 30 on one side of the pair of brackets 30 in the vehicle width direction. The fragile portion 52 is located on the other side of the front end portion 24 of the fuel tank 22 in the vehicle width direction. The weakened portion 52 is provided between the pair of brackets 30 of the third cross member 16 .

[0036] Next, the effects will be described. In the second embodiment, as in the first embodiment, the cross-sectional strength of the third cross member 16 is minimum at the weakened portion 52. Further, the section strength of the third cross member 16 is constant and higher than the section strength of the weak portion 52 in the portion of the extension portion 44 excluding the weak portion 52 . Also, unlike the first embodiment, the third cross member 16 is formed of two members, a bottom plate portion 48 extending between a pair of side members 14 and a main plate portion 50, and the members are not joined at the boundary portion 47 between the extension portion 44 and the widening portion 46 as in the first embodiment. Also, unlike the first embodiment, the reinforcing portion 32 is not provided at the boundary portion 47 between the extending portion 44 and the widened portion 46 . Therefore, the cross-sectional strength of the third cross member 16 gradually increases from both longitudinal ends of the extension portion 44 to the vehicle width outer side of the widened portion 46, and becomes maximum at the vehicle width outer end of the widened portion 46. In this case, since no reinforcing portion 32 is provided at the boundary portion 47 between the extension portion 44 and the widening portion 46, the cross-sectional strength of the third cross member 16 does not decrease to a lower value in the portion where the reinforcing portion 32 is not located as it extends from the boundary portion 47 to the outside in the vehicle width direction. Therefore, in the second embodiment, as in the first embodiment, the boundary portion 47 between the extension portion 44 and the widened portion 46 of the third cross member 16 is prevented from breaking during a side collision.

[0037] Therefore, according to the second embodiment, as shown in Figure 8, in the event of a side collision, the portion of the third cross member 16 directly below the front end 24 of the fuel tank 22 or on one side of the vehicle width direction (outside in the vehicle width direction) of the front end 24 bends downward, thereby preventing the portion of the third cross member 16 directly below the front end 24 or the portion of the third cross member 16 on one side of the vehicle width direction (outside in the vehicle width direction) of the front end 24 from moving to one side in the vehicle width direction (outside in the vehicle width direction). Therefore, the portion directly below front end 24 or to one side in the vehicle width direction (outside in the vehicle width direction) of front end 24 can be prevented from moving relatively to one side in the vehicle width direction with respect to front end 24, which prevents front end 24 from falling off first mounting member 36 and is advantageous in preventing fuel tank 22 from interfering with surrounding vehicle mounted components, such as the propeller shaft 20.

[0038] Moreover, in the second embodiment, the same effects as those of the first embodiment are achieved, except for the effects achieved by the reinforcing portion 32 among the effects of the first embodiment. In addition, in the second embodiment, the third cross member 16 is composed of two components, a bottom plate portion 48 and a main body plate portion 50, and the reinforcing portion 32 that was necessary in the first embodiment is omitted, which is advantageous in simplifying the configuration of the third cross member 16, reducing component costs, and making it lighter.

[0039] In the embodiment, the chassis frame 12 is described as having five cross members, namely, a first, second, third, fourth and fifth cross members; however, the number of cross members is arbitrary, and the cross member to which the front end 24 of the fuel tank 22 is attached with the first mounting member 36 is not limited to the third cross member 16. [Explanation of symbols]

[0040] 10 Vehicles 12 Chassis frame 14 Side member 16 Third cross member (cross member) 18 Fourth cross member 20 Propeller shaft 22 Fuel Tank 23 Tank body 24 Front end 26 Extension 2602 Upper extension 2602A top side 2604 Lower extension 2610 Ridgeline 28 Widening section 2802 Upper widening section 2804 Lower widening section 2810 Ridgeline 29 Boundary 30 Bracket 32 Reinforcement 32A Reinforcement 3210 Ridgeline 34 Weakened part 34A Recess 34B hole 34C Recess 36 First mounting member 36A Belt-shaped member 38 Second mounting member 38A Belt-shaped member 40 Third mounting member 40A Belt-shaped member 42 Tank Tray 42A, 42B, 42C locations 4202 Groove 44 Extension 4402 Top surface 46 Widening section 47 Boundary 48 Bottom plate part 50 Main body plate 52 Weakened part 52A Recess

Claims

1. A pair of side members extending in a vehicle front-rear direction; a fuel tank disposed on one side in a vehicle width direction between the pair of side members; a cross member extending in a vehicle width direction to connect the pair of side members and supporting a front end portion of the fuel tank on one side in the vehicle width direction; a mounting member for mounting the front end portion to the cross member, The cross member is provided with a weak portion on the other side in the vehicle width direction relative to the front end portion, A reinforcing portion is provided in a portion of the cross member located immediately below the front end portion or on one side of the front end portion in the vehicle width direction. A vehicle structure characterized by:

2. A pair of side members extending in a vehicle front-rear direction; a fuel tank disposed on one side in a vehicle width direction between the pair of side members; a cross member extending in a vehicle width direction to connect the pair of side members and supporting a front end portion of the fuel tank on one side in the vehicle width direction; a mounting member for mounting the front end portion to the cross member, The cross member is composed of two members: a bottom plate portion that constitutes the bottom of the cross member over the entire length in the vehicle width direction, and a main body plate portion that is arranged above the bottom plate portion, constitutes the remaining entire length of the cross member in the vehicle width direction excluding the bottom portion, and has widening portions at both ends in the vehicle width direction that are widened outwardly; A weak portion is provided at a portion of the cross member on the other side in the vehicle width direction from the front end portion. A vehicle structure characterized by:

3. The weakened portion is configured to include a recess, a hole, or a notch provided in the cross member.

3. A vehicle structure according to claim 1 or 2.

4. The cross member has an extension portion extending in a vehicle width direction, and a widened portion formed of a separate member from the extension portion and joined to both ends of the extension portion in the vehicle width direction, the widened portion being wider toward the outside, The reinforcing portion is provided across the extension portion and the widened portion at a boundary between the extension portion and the widened portion on one side in the vehicle width direction.

4. A vehicle structure according to claim 1 or claim 3 which cites claim 1.

5. The fragile portion is provided on an upper surface of the extension portion, The widened portion is such that the lower surface of the cross member extends linearly in the vehicle width direction, and the upper surface of the cross member is widened upward.

5. The vehicle structure according to claim 4.

6. the extension portion has a pair of brackets supporting a propeller shaft on the other side of the front end portion in the vehicle width direction, The weakened portion is provided between the pair of brackets.

6. The vehicle structure according to claim 5.

7. The front end portion is disposed adjacent to the pair of brackets on one side in the vehicle width direction.

7. The vehicle structure according to claim 6.

8. the front end portion is formed by a portion of a front end of the fuel tank protruding forward of the vehicle, The mounting member is a belt-shaped member that fastens the front end portion to the cross member.

8. A vehicle structure according to claim 1, wherein the vehicle structure comprises a first portion and a second portion.

9. One end of the belt-shaped member in the longitudinal direction is attached to one of the pair of brackets on one side in the vehicle width direction, and the other end is attached to the widening portion. A vehicle structure according to claim 8, which cites any one of claims 2, 4, 5, 6 and 7.

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