A straddle-type vehicle comprises a pair of vehicle body frames arranged in a vehicle width direction of a vehicle body and extending in a vehicle length direction of the vehicle body, a fuel tank placed between the pair of vehicle body frames, a tank bracket fastened to an upper surface of the fuel tank, and a support member which couples the tank bracket to at least one of the pair of vehicle body frames. The support member includes a frame coupling section detachably coupled to a mounting section provided on at least one of the pair of vehicle body frames, and a tank coupling section placed inward in the vehicle width direction relative to the frame coupling section and detachably coupled to the tank bracket.

CROSS-REFERENCE TO THE RELATED APPLICATION

This application claims priority to and the benefit of Japanese Patent Application No. 2014-165807, filed Aug. 18, 2014, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a straddle-type vehicle such as a motorcycle or an all-terrain vehicle (ATV).

Description of the Related Art

In an exemplary straddle-type vehicle, the rear portion of a fuel rank is placed between a pair of vehicle body frames in the vehicle width direction of a vehicle body. For example, Japanese Laid-Open Patent Application Publication No. 2012-136156 discloses a straddle-type vehicle in which a mounting bracket is fastened to the upper wall of the rear portion of a fuel tank. The pair of vehicle body frames include a pair of protruding sections, respectively, extending inward in the vehicle width direction toward the mounting bracket. The fuel tank is placed on the pair of vehicle body frames from above and then the mounting bracket is fastened to the pair of protruding sections. In this way, the fuel tank is supportedly mounted to the pair of vehicle body frames.

SUMMARY OF THE INVENTION

In the above-described tank support structure, however, it is necessary to set the width of the rear portion of the fuel tank to be smaller than a spacing (distance) between the pair of protruding sections. Therefore, it is difficult to increase the volume of the fuel tank.

According to an aspect of the present invention, a straddle-type vehicle comprises a pair of vehicle body frames arranged in a vehicle width direction of a vehicle body and extending in a vehicle length direction of the vehicle body; a fuel tank placed between the pair of vehicle body frames; a tank bracket fastened to an upper surface of the fuel tank; and a support member which couples the tank bracket to at least one of the pair of vehicle body frames. The support member includes a frame coupling section detachably coupled to a mounting section provided on at least one of the pair of vehicle body frames; and a tank coupling section placed inward in the vehicle width direction relative to the frame coupling section and detachably coupled to the tank bracket.

In accordance with this configuration, the support member is detachably mounted to the vehicle body frames and the fuel tank. The fuel tank is placed from above into a region between the pair of vehicle body frames in a state in which the support member is detached from the vehicle body frames, and then the frame coupling section of the support member is coupled to the vehicle body frames. In this way, the fuel tank is supportedly mounted to the vehicle body frames. In this assembly sequence, even when the width of the fuel tank is increased to be close to the spacing between the vehicle body frames, it becomes possible to prevent an interference of the fuel tank with the vehicle body frames and the members fastened to the vehicle body frames by placing the fuel tank between the vehicle body frames in the above-described manner. Therefore, the volume of the fuel tank of the straddle-type vehicle can be increased.

The above and further objects, features, and advantages of the present invention will more fully be apparent from the following detailed description of a preferred embodiment with the accompanying drawings.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the embodiment of the present invention will be described with reference to the drawings. Throughout the drawings, the same or corresponding components are designated by the same reference symbols, and will not be described repeatedly. A forward and rearward direction corresponds with the vehicle length direction of a vehicle body of the straddle-type vehicle, and a rightward and leftward direction corresponds with the vehicle width direction of the vehicle body. The term “inward in the vehicle width direction” is defined as a direction closer to the center of the vehicle body in the vehicle width direction, while the term “outward in the vehicle width direction” is defined as a direction away from the center of the vehicle body in the vehicle width direction.

A motorcycle which is exemplarily shown inFIG. 1is a suitable example of a straddle-type vehicle100. The straddle-type vehicle100includes a pair of right and left vehicle body frames1R,1L (right vehicle body frame1R is shown inFIG. 2), a fuel tank2, and a seat3. The pair of vehicle body frames1R,1L are arranged in the vehicle width direction and extend in the vehicle length direction. The pair of right and left vehicle body frames1R,1L are symmetric in the vehicle width direction with respect to the center of the vehicle body in the vehicle width direction. The pair of right and left vehicle body frames1R,1L extend separately rearward from a head pipe4supporting a steering shaft5which changes the direction of a front wheel6. The fuel tank2reserves fuel supplied to an engine7for driving a rear wheel8. The engine7is mounted to the pair of right and left vehicle body frames1R,1L. The engine7is covered with the fuel tank2from above. A seat3is placed rearward relative to the fuel tank2.

The left vehicle body frame1L includes a front frame9L extending rearward from the head pipe4, and a rear frame10L extending rearward from the rear portion of the front frame9L. The rear frame10L is manufactured separately from the front frame9L and coupled to the rear portion of the front frame9L by use of a coupling member (e.g., bolt). As shown inFIG. 2, the right vehicle body frame1R includes a front frame9R and a rear frame10R, and the rear frame10R is manufactured and coupled to the front frame9R in the same manner as that for the front and rear frames9L,10L of the left vehicle body frame1L. The pair of front frames9R,9L are welded to the head pipe4and thus integrated. The pair of rear frames10R,10L are manufactured separately.

As shown inFIG. 2, a “frame spacing” is not constant in the vehicle length direction. The term “frame spacing” is defined as a spacing or distance in the vehicle width direction between the pair of right and left vehicle body frames1R,1L, especially between the upper edges of the frames1R,1L, unless otherwise noted. The intermediate portions of the pair of vehicle body frames1R,1L in the vehicle length direction define a smaller-spacing section1awhich has a smaller frame spacing. The frame spacing increases as the vehicle body frames1R,1L extend rearward from the head pipe4, decreases as they extend rearward from a larger-spacing section1b, and increases again as they extend rearward from the smaller-spacing section1a.

Except for a region in the vicinity of the head pipe4(to be precise, in a region that is forward relative to the larger-spacing section1b), the frame spacing is smallest at the smaller-spacing section1a. The smaller-spacing section1aextends from the rear end portions of the front frames9R,9L to the front end portions of the rear frames10R,10L. The pair of front frames9R,9L constitute a section located in front of the smaller-spacing section1a, while the pair of rear frames10R,10L constitute a section located rearward relative to the smaller-spacing section1a.

As shown inFIGS. 1 and 2, the seat3is mounted to the rear frames10R,10L in such a manner that the front portion of the seat3is placed on the upper portion of the smaller-spacing section1a. A rider is seated on the front portion of the seat3in a straddle posture, and grounds one or both of the rider's feet to prevent lateral falling of the vehicle body, during a temporal stop of the straddle-type vehicle100. By providing the smaller-spacing section1a, the width of the front portion of the seat3(hereinafter will be simply referred to as “rider seat width”) can be reduced, and the rider is not forced to widely open their thighs. Therefore, the rider straddling the seat3can easily ground their feet. Thus, it becomes possible to lessen a physical burden on the rider to prevent the vehicle body from falling sideways.

At least a portion of the fuel tank2is placed between the pair of right and left vehicle body frames1R,1L and below the upper edges of the frames1R,1L (hereinafter this portion will be referred to as “frame accommodation portion”). The fuel tank2is mounted to the vehicle body frames1R,1L in such a manner that the front portion of the fuel tank2protrudes upward from the front frames9R,9L and the rear end portion of the fuel tank2constitutes the frame accommodation portion. The rear end portion of the fuel tank2extends to a location that is rearward relative to the smaller-spacing section1and is covered by the front portion of the seat3. Since the fuel tank2is expanded rearward to partially overlap with the seat3when viewed from above, the volume of the fuel tank2(hereinafter will be simply referred to as “tank volume”) can be increased.

If the width of the fuel tank2(hereinafter will be simply referred to as “tank width”) is increased, then the tank volume can be increased. In that case, if the tank width can be increased without increasing the frame spacing, the rider can easily turn the vehicle body and easily ground their feet, which is an advantage. If the frame spacing is increased, then the rider seat width is increased correspondingly, and as a result, the rider is forced to widely open their legs. In this structure, the rider cannot easily ground their feet.

The straddle-type vehicle100incorporates a tank support structure shown inFIG. 2. By use of this tank support structure, the tank width and hence the tank volume can be increased. In addition, the frame spacing is not increased, and the rider can easily turn the vehicle body and can easily ground their feet. In this tank support structure, a tank bracket20is attached to the upper surface of the fuel tank2(especially, the frame accommodation portion). The tank bracket20is coupled to the pair of vehicle body frames1R,1L via a support member30. The support member30is detachably coupled to the vehicle body frames1R,1L. The support member30protrudes outward in the vehicle width direction from the tank bracket20and the fuel tank2. The support member30is coupled to the vehicle body frames1R,1L in locations that are outward in the vehicle width direction relative to the fuel tank2. This tank support structure also serves as a seat support structure. The front portion of the seat3is supported by the support member30.

The tank support structure is assembled according to, for example, the following steps (1) to (4). (1) The support member30is coupled to the tank bracket20. (2) The fuel tank2with the support member30is placed on the vehicle body frames1R,1L from above such that the frame accommodation portion of the fuel tank2is accommodated into a region between the vehicle body frames1R,1L. (3) The support member30is coupled to the vehicle body frames1R,1L. (4) The seat3is mounted to the vehicle body frames1R,1L from above such that the front portion of the seat3is placed on the support member30. Hereinafter, the configuration of the tank support structure will be described in conjunction with steps (1) to (4).

The configuration corresponding to step (1) will now be described. As shown inFIG. 3, the support member30includes a pair of frame coupling sections31R,31L, and a pair of tank coupling sections32R,32L. The pair of frame coupling sections31R,31L are detachably coupled to the pair of vehicle body frames1R,1L, respectively. The pair of tank coupling sections32R,32L are detachably coupled to the tank bracket20.

As shown inFIG. 4, the support member30as a whole has a cross-section of a substantially hat shape. The support member30includes a bridge portion33extending in the vehicle width direction above the pair of frame coupling sections31R,31L, and a pair of longitudinal wall portions34R,34L vertically connecting the outer edge portions of the bridge portion33in the vehicle width direction to the inner edge portions of the pair of frame coupling sections31R,31L in the vehicle width direction, respectively. The pair of frame coupling sections31R,31L extend outward in the vehicle width direction from the lower edge portions of the pair of longitudinal wall portions34R,34L, respectively. The pair of tank coupling sections32R,32L protrude downward from the bridge portions33, respectively. The pair of tank coupling sections32R,32L are located inward in the vehicle with direction relative to the pair of longitudinal wall portions34R,34L, respectively.

The tank bracket20includes a plate-shaped base portion21secured to the upper surface of the rear portion of the fuel tank2, and a pair of side wall portions22extending upward from the base portion21. The pair of side wall portions22are placed to be spaced apart from each other in the vehicle width direction. The tank bracket20also includes a cylindrical portion23extending in the vehicle width direction and penetrating the pair of side wall portions22.

In step (1), a cylindrical damper member24is internally fitted to the cylindrical portion23of the tank bracket20. A cylindrical collar25is internally fitted to the cylindrical damper member24. The support member30is provided on the tank bracket20in such a manner that the members22to25are sandwiched between the pair of tank coupling sections32R,32L. The pair of tank coupling sections32R,32L have a pair of pivot insertion holes35R,35L, respectively, penetrating therethrough in the vehicle width direction. The pair of pivot insertion holes35R,35L are in communication with inside of the collar25. A pivot shaft26is inserted into the collar25and fastened to the tank coupling sections32R,32L. In this state, the axis of the pivot shaft26extends in the vehicle width direction, and the fuel tank2is coupled to the support member30such that the fuel tank2is angularly displaceable around the axis of the pivot shaft26.

The pivot shaft26is, for example, a through bolt including a head portion, a shaft portion, and a male thread portion. In this case, the shaft portion of the pivot shaft26is inserted into the pivot insertion holes35R,35L and the collar25, the head portion is pressed against the outer surface of one of the tank coupling sections32R,32L, the male thread portion protrudes outward in the vehicle width direction from the other of the tank coupling sections32R,32L, and a nut27is tightened into the male thread portion. By loosening the nut27and pulling out the pivot shaft26, the support member30can be detached from the bracket20.

The pair of longitudinal wall portions34R,34L include through holes36R,36L, respectively, penetrating therethrough in the vehicle width direction. Therefore, by inserting the pivot shaft26from a location that is outward in the vehicle width direction relative to one of the through holes36R,36L, into the one of the through holes36R,36L, one of the pivot insertion holes35R,35L, and the collar25in this order, the pivot shaft26can be easily set. Also, the pivot shaft26can be fastened while looking at the other of the coupling sections32R,32L, from a location that is outward in the vehicle width direction relative to the other of the through holes36R,36L. Even when the support member30has the cross-section of the hat shape and the tank coupling sections32R,32L are hidden by the longitudinal wall portions34R,34L, respectively, the operation for coupling the tank bracket20to the tank coupling sections32R,32L can be easily carried out.

The configuration corresponding step (2) will now be described. As shown inFIG. 2, the left vehicle body frame1L is provided with a mounting section41L in a location that is rearward relative to the intermediate portion of the left vehicle body frame1L, defining the smaller-spacing section1a, and the mounting section41L protrudes inward in the vehicle width direction from the inner surface of the left vehicle body section1L. The right vehicle body frame1R is provided with a mounting section41R in the same manner as that for the mounting section41L of the vehicle body frame1L. A spacing (distance) between the pair of mounting sections41R,41L in the vehicle width direction is equal to or larger than the frame spacing at the smaller-spacing section1a.

In step (2), the rear portion of the fuel tank2is accommodated into a region between the pair of vehicle body frames1R,1L, from above. In a region in the vicinity of the mounting sections41R,41L, the fuel tank2is accommodated into a region between the pair of mounting sections41R,41L, from above. The support member30protrudes outward in the vehicle width direction from the fuel tank2in a state in which the support member30is coupled to the tank bracket20. The pair of frame coupling sections31R,31L are located on the outer end portions of the support member30in the vehicle width direction, respectively. The fuel tank2does not interfere with each of the pair of mounting sections41R,41L, while the pair of frame coupling sections31R,31L are placed on the mounting sections41R,41L to overlap with the mounting sections41R,41L, respectively, from above.

The configuration corresponding to step (3) will now be described. As shown inFIG. 4, the left frame coupling section31L has a plate shape including a flat upper surface and a flat lower surface which are parallel to each other, and includes one or more coupling member insertion holes37L penetrating therethrough vertically. In contrast, the left mounting section41L includes a horizontal placement surface42L, and one or more coupling member engagement holes43L which open in the placement surface42L. The lower surface of the flame coupling section31L and the placement surface42L of the left mounting section41L are an interface of the frame coupling section31L and of the mounting section41L which are joined together. The lower surface of the flame coupling section31L is placed on the placement surface42L of the mounting section41L, and the coupling member insertion hole37L is aligned with the corresponding coupling member engagement hole43L. The right frame coupling section31R has the same configuration as that of the left frame coupling section31L. The right frame coupling section31R and the right mounting section41R have the same configurations as those of the left frame coupling section31L and the left mounting section41L, respectively.

In step (3), in the left frame coupling section31L, one or more coupling members44L are inserted into the corresponding coupling member insertion holes37L and the corresponding coupling member engagement holes43L, from above. The coupling member44L is, for example, a tap bolt. In this case, the coupling member engagement hole43L is a female thread provided on the rear frame10L preliminarily by a tap process or a nut insertion process. The coupling member44L is threadedly engaged with the coupling member engagement hole43L, and the head portion of the tap bolt is tightened against the upper surface of the frame coupling section31L. In the same manner, in the right frame coupling section31R, one or more coupling members44R are inserted into the corresponding coupling member insertion holes37R and the corresponding coupling member engagement holes43R, from above. By disengaging the coupling members44R,44L, the support member30can be disengaged from the vehicle body frames1R,1L.

The fuel tank2is angularly displaceably coupled to the pair of vehicle body frames1R,1L via the support member30. The axis of the pivot shaft26is set in the rear portion of the fuel tank2. The front portion of the fuel tank2can be pivoted upward around the pivot shaft26in a state in which the fuel tank2is coupled to the vehicle body frames1R,1L. This makes it possible to carry out the operation for assembling the fuel system of the engine7and the operation for maintaining the fuel system, in the state in which the fuel tank2is coupled to the vehicle body frames1R,1L. After the operation for assembling the fuel system of the engine7is finished, the front portion of the fuel tank2is lowered down and mounted to the vehicle body frames1R,1L.

As shown inFIGS. 2 and 5, the interface of the frame coupling section31R and of the mounting section41R protrudes rearward farther than the axis of the pivot shaft26does. In this structure, even when the fuel tank2is angularly displaced around the axis of the pivot shaft26extending in the vehicle width direction, the fuel tank2can be supported stably. In the present embodiment, the left coupling member44L includes a front left coupling member44La and a rear left coupling member44Lb. In correspondence with this, the left coupling member insertion hole37L includes a front left hole37La and a rear left hole37Lb, and the left coupling member engagement hole43L includes a front left hole43La and a rear left hole43Lb. The two coupling members44La,44Lb are placed at a front side and a rear side of the axis of the pivot shaft26, respectively. The right coupling members44R (44Ra,44Rb), the right coupling member insertion holes37R (37Ra,37Rb), and the right coupling member engagement holes43R (43Ra,43Rb) have the same configurations as those of the left coupling members44L (44La,44Lb), the left coupling member insertion holes37R (37Ra,37Rb), and the left coupling member engagement holes43L (43La,43Lb), respectively. Since the frame coupling sections31R,31L are coupled to the vehicle body frames1R,1L, respectively in the above-described manner, the fuel tank2can be supported stably such that the fuel tank2is angularly displaceable around the axis of the pivot shaft26.

The configuration corresponding to step (4) will now be described. As shown inFIGS. 2, 3, and 5, the support member30includes a pair of seat placement sections38R,38L. The pair of seat placement sections38R,38L protrude forward in a tongue shape from the outer edge portions of the bridge portion33in the vehicle width direction or the pair of longitudinal wall portions34R,34L, respectively. In a state in which the frame coupling sections31R,31L are coupled to the mounting sections41R,41L, respectively, the pair of seat placement sections38R,38L are placed between the intermediate portions of the vehicle body frames1R,1L, defining the smaller-spacing section1a, and away from and above the fuel tank2. In contrast, the front portion of the seat3has an inverted-U shape, and a pair of projections45R,45L are provided on the lower surface of a ceiling wall of the front portion of the seat3.

In step (4), as shown inFIGS. 2 and 5, the seat3is mounted to the vehicle body frames1R,1L (to be precise, the rear frames10R,10L) in such a manner that the upper portion of the smaller-spacing section1ais covered by the front portion of the seat3and the projections45R,45L of the seat3are placed on the pair of seat placement sections38R,38L, respectively. This can realize a structure in which the fuel tank2is placed between the pair of vehicle body frames1R,1L, the support member30is placed above the rear portion of the fuel tank2in a state in which the support member30overlaps with the fuel tank2when viewed from above, and the fuel tank2is partially covered by the front portion of the seat3from above.

In the aforementioned tank support structure, the support member30includes the pair of frame coupling sections31R,31L, and the pair of tank coupling sections32R,32L. The pair of frame coupling sections31R,31L are detachably coupled to the pair of mounting sections41R,41L provided on the pair of vehicle body frames1R,1L, respectively, and the pair of tank coupling sections32R,32L are placed inward in the vehicle width direction relative to the pair of frame coupling sections31R,31L, respectively and detachably coupled to the tank bracket20. Because of this structure, the fuel tank2can be mounted to the vehicle body frames1R,1L, in a state in which members used to couple the fuel tank2to the vehicle body frames1R,1L are omitted from the vehicle body frames1R,1L. Therefore, even when the tank width is increased to be close to the frame spacing, the frame accommodation portion of the fuel tank2can be accommodated into the region between the pair of vehicle body frames1R,1L, without an interference of the fuel tank2with the vehicle body frames1R,1L and the members fastened to the vehicle body frames1R,1L. Therefore, the tank width can be increased, while avoiding an increase in the frame spacing.

The support member30protrudes outward in the vehicle width direction from the fuel tank2, and the pair of frame coupling sections31R,31L are coupled to the mounting sections41R,41L, respectively, in locations that are outward in the vehicle width direction relative to the fuel tank2. In this configuration, even if the members used to couple the fuel tank2to the vehicle body frames1R,1L extend inward in the vehicle width direction from the vehicle body frames1R,1L toward the fuel tank2, these members can be omitted from the vehicle body frames1R,1L by detaching the support member30from the vehicle body frames1R,1L. Therefore, the tank width can be easily increased to be close to the frame spacing.

The support member30includes the seat placement sections38R,38L on which the rider's seat3is placed from above. Because of this structure, the support member30can serve to couple the fuel tank2to the vehicle body frames1R,1L and serve to support the seat3. Therefore, the configuration of the straddle-type vehicle100can be simplified. The fuel tank2can be mounted to the vehicle body frame1R,1L, in a state in which the members used to couple the seat3to the vehicle body frames1R,1L are omitted from the vehicle body frames1R,1L. Therefore, the tank width can be easily increased to be close to the frame spacing.

The support member30is coupled to both of the pair of vehicle body frames1R,1L, and extends in the vehicle width direction. The pair of vehicle body frames1R,1L are coupled to each other via the support member30. This can enhance the stiffness of the vehicle body frames1R,1L. Since the support member30serves to couple the fuel tank2to the vehicle body frames1R,1L and enhance the stiffness of the vehicle body frames1R,1L, the configuration of the straddle-type vehicle100can be simplified.

The frame coupling sections31R,31L form a pair in the vehicle width direction, and the seat placement sections38R,38L form a pair in the vehicle width direction. In this configuration, since the front portion of the seat3is supported at two points which are apart in the axial direction, the seat3can be supported stably. Since the pair of vehicle body frames1R,1L can support the weight load of the rider and the fuel tank2in a dispersed manner, the weight of the vehicle body frames1R,1L can be reduced and the structure of the vehicle body frames1R,1L can be simplified, while ensuring the support stiffness of the support member30and of the vehicle body frames1R,1L.

The pair of vehicle body frames1R,1L include the mounting sections41R,41L to which the support member30is detachably coupled, instead of the members used to couple the fuel tank2to the vehicle body frames1R,1L and the members used to couple the seat3to the vehicle body frames1R,1L. The mounting sections41R,41L are provided in the locations that are rearward relative to the intermediate portions of the vehicle body frames1R,1L, defining the smaller-spacing section1a. In this structure, it is not necessary to make the tank width smaller than frame spacing at the smaller-spacing section1awhich is set as small as possible, to avoid an interference of the fuel tank2with the mounting sections41R,41L. Therefore, the tank width can be set to a sufficiently large one.

The seat placement sections38R,38L are placed in front of the frame coupling sections31R,31L, respectively. Since the front portion of the seat3is placed on the seat placement sections38R,38L in a location that is as forward as possible, the seat3can be stably supported. Since the mounting sections41R,41L are located rearward relative to the smaller-spacing section1aand the seat placement sections38R,38L are located in front of the frame coupling sections31R,31L, the tank width can be increased, and the seat3can be stably supported.

The frame coupling sections31R,31L are coupled to the vehicle body frames1R,1L, respectively, in a state in which the frame coupling sections31R,31L are placed on the mounting sections41R,41L to overlap with the mounting sections41R,41L, respectively, from above. This makes it possible to avoid a situation in which a strong shear load caused by the weight load of the rider and the fuel tank2is applied to the surface of the frame coupling section31R and the surface of the mounting section41R which are joined together, and to the surface of the frame coupling section31L and the surface of the mounting section41L which are joined together. Therefore, the support member30can be mounted to the vehicle body frames1R,1L with a high reliability.

The mounting sections41R,41L protrude inward in the vehicle width direction from the inner surfaces of the vehicle body frames1R,1L (rear frames10R,10L), respectively. However, the spacing (distance) between the pair of mounting sections41R,41L in the vehicle width direction is not smaller than the frame spacing at the smaller-spacing section1a. Because of this, the tank width can be increased, and mounting reliability can be improved. Further, the members (e.g., the coupling member engagement holes43R,43L, the coupling members44R,44L) used to couple the frame coupling sections31R,31L to the mounting sections41R,41L can be covered by the vehicle body frames1R,1L, and are not seen from outside. As a result, the external appearance of the straddle-type vehicle100is less likely to be degraded.

This will be described more specifically. The front portions of the rear frames10R,10L constitute the side walls which are vertically elongated. In this structure, the placement surfaces42R,42L can be located below the upper edges of the rear frames10R,10L, respectively. Further, the coupling member engagement holes43R,43L extending downward from the placement surfaces42R,42L, respectively, can be located above the lower edges of the rear frames10R,10L, respectively. Moreover, in the locations where the mounting sections41R,41L are provided, the rear frames10R,10L are vertically elongated. Therefore, even when a downward load caused by the weight of the rider or the like is applied to the rear frames10R,10L, the rear frames10R,10L are less likely to be deformed. In this way, the good external appearance of the straddle-type vehicle100can be maintained, and the support stiffness of the straddle-type vehicle100can be enhanced.

The seat placement sections38R,38L are located above the frame coupling sections31R,31L, respectively, and coupled to the frame coupling sections31R,31L via the longitudinal wall portions34R,34L, respectively. Since the modulus of the sections of the longitudinal wall portions34R,34L with respect to the downward load is large, the support stiffness of the support member30and of the vehicle body frames1R,1L can be enhanced. The frame coupling sections31R,31L are placed below the upper edges of the vehicle body frames1R,1L, respectively. Therefore, even when the seat placement sections38R,38L are placed above the frame coupling sections31R,31L, respectively, the height of the seat3is not increased. Therefore, the support stiffness can be enhanced, and the rider can easily ground their feet.

The seat placement sections38R,38L are located closer to the frame coupling sections31R,31L in the vehicle width direction, than the tank coupling sections32R,32L are, respectively. The seat placement sections38R,38L can be made as close to the vehicle body frames1R,1L as possible, respectively. This makes it possible to prevent a situation in which a strong bending load corresponding to the downward load from the seat3is applied to the locations (e.g., longitudinal wall portions34R,34L) at which the seat placement sections38R,38L are coupled to the frame coupling sections31R,31L, respectively. Therefore, the support stiffness of the support member30and of the vehicle body frames1R,1L can be enhanced.

The above-described embodiment is merely exemplary, and the above-described configuration may be suitably changed within the scope of the invention. For example, the support member30may not support the seat3. Even in that case, the tank width can be easily increased to be close to the frame spacing, if the members used to support the seat3are detachably coupled to the vehicle body frames1R,1L.

The assembling steps of the tank support structure are not limited to the above-described steps (1) to (4), so long as the frame accommodation portion of the fuel tank2is accommodated into the region between the vehicle body frames1R,1L, before the support member30is mounted to the vehicle body frames1R,1L. Steps (1) to (3) may be modified into the following steps (1A) to (3A), and steps (2A) and (3A) may be reversed. (1A) The fuel tank2is positioned with respect to the vehicle body frames1R,1L without the support member30in such a manner that the frame accommodation portion of the fuel tank2is accommodated into the region between the vehicle body frames1R,1L from above. (2A) The support member30is coupled to the tank bracket20. (3A) The support member30is coupled to the vehicle body frames1R,1L.

The use of the member used to couple the fuel tank2to the vehicle body frames1R,1L is not limited to a case where the support member30which is a single member is coupled to both of the pair of vehicle body frames1R,1L, so long as the member is detachably coupled to at least one of the pair of vehicle body frames1R,1L. For example, a pair of support members may be separately coupled to the pair of vehicle body frames1R,1L, respectively. Further, one or more support members may be coupled to only one of the pair of vehicle body frames1R,1L.

The present invention is suitably used in straddle-type vehicles such as an automated three-wheeled vehicle or an ATV (all-terrain vehicle) as well as a motorcycle.