JP2012001046A - Fuel tank and fuel tank structure of motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel tank and a fuel tank structure of a motorcycle that include a plurality of swelling parts protruding upward and that have an increased ratio of a filling amount of fuel to the internal volume by suitably exhausting air from the swelling parts.SOLUTION: The fuel tank 23 includes: a container 71 having a front-swelling part 72 and a rear-swelling part 75 which protrude upward, a trough part 81 between the swelling parts 72 and 75, and a filler-port structure 82 which is provided on the front-swelling part 72; and a vent pipe part 83 having one opening end 83a which is arranged in the front-swelling part 72 and the other opening end 83b which is arranged in the rear-swelling part 75, and connecting the insides of the front-swelling part 72 and the rear-swelling part 75.

Description

  The present invention relates to a fuel tank and a fuel tank structure for a motorcycle.

  Motorcycles and automobiles include a fuel tank that stores liquid fuel, such as gasoline.

  The fuel tank is preferably large in order to increase the cruising range of motorcycles and automobiles. However, if the fuel tank is too large, other aspects such as ease of living and securing of installation space for other equipment, operability, etc. It will adversely affect the characteristics. Therefore, it is not a simple shape such as a cylindrical shape, a rectangular parallelepiped shape, or a spherical shape, but a complicated shape corresponding to the shape of a motorcycle or automobile, and the internal volume is made as much as possible by effectively utilizing the space of the installation location. There is an expanded fuel tank. For example, a fuel tank having a plurality of bulging portions with respect to a horizontal plane of a virtual vehicle corresponding to the shape of a motorcycle is known (for example, see Patent Document 1).

JP 2003-112678 A

  A fuel tank provided with a plurality of bulges with respect to a horizontal plane cannot be filled with fuel unless the air in the bulges is appropriately exhausted. That is, a fuel tank having a plurality of bulges can secure a volume as large as possible corresponding to the shape of the vehicle, but if this bulge becomes an air reservoir, the fuel volume fills the internal volume of the fuel tank. The proportion of the amount will be small.

  For example, the fuel tank described in Patent Literature 1 includes a front bulge portion disposed in front of the vehicle and a rear bulge portion that extends upward toward the rear of the vehicle. In such a fuel tank, unless the air is appropriately exhausted from the front and rear bulging portions, each bulging portion becomes an air reservoir, and the ratio of the fuel filling amount to the internal volume of the fuel tank becomes small.

  Accordingly, the present invention provides a fuel tank and a motorcycle having a plurality of bulging portions protruding upward and appropriately evacuating air from these bulging portions to increase the ratio of the fuel filling amount to the internal volume. The purpose is to propose a fuel tank structure.

  In order to solve the above problems, the fuel tank according to the present invention includes a first bulging portion protruding upward, a second bulging portion, a valley between the bulging portions, and the first bulging portion. A container having a fuel filler structure provided; one open end disposed in the first bulge and the other open end disposed in the second bulge; And a vent pipe that communicates the inside of the bulge and the inside of the second bulge.

  The motorcycle fuel tank structure according to the present invention has a pair of left and right main frames extending in the front-rear direction of the vehicle, an engine mounted on the lower side of the main frame, and a substantially L-shape in a side view of the vehicle. A fuel tank formed and a seat seat held by the fuel tank, the fuel tank being disposed behind the engine and extending up and down the vehicle; and the front expansion A lower half bottom portion that extends continuously from the bottom of the projecting portion and extends rearward of the vehicle, and is disposed rearward of the front bulge portion and extends upwardly toward the rear of the vehicle continuously from the lower half bottom portion. A rear bulge portion, a fuel filler structure provided in the front bulge portion, one opening end disposed in the front bulge portion, and the other disposed in the vicinity of the rear end upper portion in the rear bulge portion In the front bulge part having an open end of Anda vent tube portion which communicates with said rear bulging portion, wherein the seat bottom is characterized in that it is disposed above the rear bulging portion.

  According to the present invention, there are provided a fuel tank and a motorcycle having a plurality of bulging portions protruding upward and appropriately evacuating air from these bulging portions to increase the ratio of the fuel filling amount to the internal volume. A fuel tank structure can be proposed.

The left view which showed the motorcycle provided with the fuel tank and fuel tank structure which concern on embodiment of this invention. 1 is a left side view showing a fuel tank structure of a fuel tank and a motorcycle according to an embodiment of the present invention. 1 is a left side view showing a fuel tank structure of a fuel tank and a motorcycle according to an embodiment of the present invention. 1 is a left side view showing a fuel tank structure of a fuel tank and a motorcycle according to an embodiment of the present invention. 1 is a rear view showing a fuel tank structure of a fuel tank and a motorcycle according to an embodiment of the present invention. The side view which showed the fuel tank which concerns on embodiment of this invention. 1 is a longitudinal sectional view showing a fuel tank according to an embodiment of the present invention. The perspective view which showed the fuel tank which concerns on embodiment of this invention. The figure which showed the mode of the fuel with which the fuel tank which concerns on embodiment of this invention was filled. The figure which showed the mode of the fuel with which the fuel tank which concerns on embodiment of this invention was filled.

  Embodiments of a fuel tank and a fuel tank structure for a motorcycle according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a left side view showing a motorcycle provided with a fuel tank and a fuel tank structure according to an embodiment of the present invention.

  In describing the structure of the motorcycle 1, the solid arrow F in FIG. 1 is defined as the front, and the solid arrow R in FIG. 1 is defined as the rear. Further, the left hand side when viewed from the passenger of the motorcycle 1 is defined as the left side of the motorcycle 1 and the opposite side is defined as the right side of the motorcycle 1. Furthermore, the head side of the passenger of the motorcycle 1 is defined as the upper side of the motorcycle 1 and the opposite side is defined as the lower side of the motorcycle 1. The direction of each part constituting the motorcycle 1 is the same as that of the motorcycle 1.

  As shown in FIG. 1, a motorcycle 1 includes a vehicle body frame 2, an engine 5 mounted on the vehicle body frame 2, a steering mechanism 6 pivotally supported on the front end portion of the vehicle body frame 2, and a lower end portion of the steering mechanism 6. A front wheel 8 pivotally supported on the vehicle, a front wheel suspension device 11 provided on the steering mechanism 9, a swing arm 12 pivotally supported on the rear portion of the body frame 2 so as to be swingable in the vertical direction, and a rear end of the swing arm 12 And a rear wheel suspension device 15 connected between the vehicle body frame 2 and the swing arm 12.

  The body frame 2 is of a twin tube type, for example. The vehicle body frame 2 includes a head pipe 16 disposed at a front end, a pair of left and right main frames 17 that expands in the left-right direction immediately after the head pipe 16 and extends obliquely rearward and downward to serve as a tank rail, and a main frame 17 is provided with a pair of left and right center frames 18 integrally provided at the rear end portion of the main frame 17 and extending substantially downward, and a pair of left and right seat rails 19 extending obliquely rearward and upward from the rear end portion of the main frame 17.

  The head pipe 16 pivotally supports the steering mechanism 6 via a built-in steering shaft (not shown). The center frame 18 supports a pivot shaft 21 installed at a substantially central portion in the longitudinal direction. The pivot shaft 21 pivotally supports the swing arm 12.

  The main frame 17 and the seat rail 19 support the fuel tank 23 constituting the fuel tank structure 22 from below.

  The engine 5 is disposed at the lower center of the motorcycle 1, more specifically below the main frame 17, and is connected to the engine intake system 25 and the engine exhaust system 26. The engine 5 includes a single cylinder engine, a parallel two cylinder engine, a parallel six cylinder engine, a V-type two-cylinder engine, a V-type four-cylinder engine, and a V-type six in addition to a parallel four-cylinder engine that is a four-cycle multi-cylinder engine. A cylinder engine is used as appropriate. The output of the engine 5 is transmitted to a rear wheel 13 via a driven sprocket (not shown) from a chain (not shown) constituting a secondary reduction mechanism (not shown).

  The engine 5 includes a cylinder assembly 5a including a cylinder having a fuel chamber (not shown), a valve mechanism (not shown), a cylinder head having an intake / exhaust port (not shown), and a crankshaft (not shown). And a crank assembly 5b having a transmission (not shown).

  The engine intake system 25 includes a throttle body 27 disposed above the engine 5 and an air cleaner box 28 disposed above the throttle body 27. The engine intake system 25 is a so-called downdraft system in which an intake path from an outlet tube (not shown) opened in the air cleaner box 28 to the throttle body 27 and the intake port is configured in a substantially straight line and oriented in a substantially vertical direction. This is the intake system.

  The engine exhaust system 26 includes an exhaust pipe 29 that extends downward from the front of the engine 5 to the rear of the motorcycle 1, and a muffler that is disposed on both sides of the motorcycle 1 in the vehicle width direction and connected to the exhaust pipe 29. 31. The muffler 31 extends from near both sides of the rear wheel 13 toward the upper rear side of the motorcycle 1.

  The steering mechanism 6 is pivotally supported by the head pipe 16 and the steering shaft so as to be rotatable in the left-right direction of the motorcycle 1. The steering mechanism 6 includes a steering head 33 pivotally supported on a steering shaft, a pair of left and right front forks 34 provided on the steering head 33, and a pair of handle bars provided near the upper end of the front fork 34 or on the steering head 33. 35. The left and right handlebars 35 each include a handle grip 36. A handle grip 36 disposed on the right side of the motorcycle 1 is a throttle grip 37.

  The front wheel 8 is steered so as to be rotatable left and right by a handle bar 35 of the steering mechanism 6. The front wheel 8 includes a front wheel 42 that is pivotally supported on the front fork 34 by a front wheel axle 41, a front tire 43 that is attached to the outer periphery of the front wheel 42, and a fastening member such as a bolt (not shown). And a front wheel brake plate 45 fixed by (omitted).

  The front end portion of the swing arm 12 is pivotally supported by a pivot shaft 21 provided substantially at the center in the vertical direction of the center frame 18.

  The rear wheel 13 includes a rear wheel 48 that is pivotally supported on the swing arm 12 by a rear wheel axle 47, a rear wheel tire 49 that is attached to the outer periphery of the rear wheel 48, and a bolt or the like attached to the rear wheel 48. A rear wheel brake plate (not shown) fixed by a fastening member (not shown).

  The rear wheel suspension device 15 is a shock absorber that cushions the swing arm 12 so as not to be transmitted to the vehicle body frame 2 due to the unevenness of the road surface caught by the rear wheel 13, and presses the rear wheel 13 against the road surface. It also functions. The rear wheel suspension device 15 includes a suspension unit 52 in which a spring 50 and a shock absorber 51 are combined.

  The motorcycle 1 is covered with a streamlined cowling 53 from at least a part of the vehicle, for example, from the front to the lower center. The cowling 53 reduces the air resistance during the traveling of the motorcycle 1 and protects the rider from the traveling wind pressure. The cowling 53 is connected to the front cover 55 covering the front of the vehicle, a pair of left and right side covers 56 covering the sides of the engine 5, an air cleaner box cover 57 covering the air cleaner box 28, and the air cleaner box cover 57. And a seat cowl 58 that covers the fuel tank 23 and covers the rear of the vehicle. The seat cowl 58 supports the seating seat 59.

  2 to 4 are left side views showing a fuel tank structure of a fuel tank and a motorcycle according to an embodiment of the present invention.

  FIG. 3 is a view obtained by removing the seat cowl 58 and the seating seat 59 from FIG. 4 is a view in which the seat cowl 58, the seating seat 59, and the bottom cover 61 are removed from FIG.

  FIG. 5 is a rear view showing the fuel tank structure of the fuel tank and the motorcycle according to the embodiment of the present invention.

  As shown in FIGS. 2 to 5, the fuel tank structure 22 of the motorcycle 1 includes a pair of left and right main frames 17 extending in the front-rear direction of the vehicle, an engine 5 mounted on the lower side of the main frame 17, and a vehicle side surface. A fuel tank 23 formed in a substantially L-shape when viewed and a seating seat 59 held in the fuel tank 23 are provided.

  The fuel tank structure 22 is disposed in a space between the engine 5 and the fuel pump 64 and is connected to the upper end connected to the rear end portion of the main frame 17 or the upper end portion of the center frame 18 and the swing arm 12. A suspension unit 52 having a lower end.

  Further, the fuel tank structure 22 includes a pair of left and right seat rails 19 that are provided on the main frame 17 and support the fuel tank 23 from below the fuel tank 23 and are disposed on the inner side of the width of the fuel tank 23.

  Furthermore, the fuel tank structure 22 includes a front fixing bracket 65 provided on the main frame 17 for supporting the fuel tank 23 on the main frame 17, and a fuel tank 23 sandwiched between the starting ends of the seat rails 19 provided on the fuel tank 23. 23 is supported by the seat rail 19, the front fastening member 67 is fastened to the fuel tank 23, and the rear fastening member 68 is fastened to the seat rail 19. And a rubber elastic body 69 provided at the rear end portion of the seat rail 19.

  The fuel tank structure 22 includes a seat cowl 58 that covers a part of the fuel tank 23, and a bottom cover 61 that covers the fuel tank 23 together with the seat cowl 58.

  The main frame 17 is a frame that is inclined so that the front side of the vehicle becomes higher and extends in the front and rear of the vehicle, and supports the air cleaner box 28 above the engine 5 and on the front side of the fuel tank 23.

  The fuel tank 23 is a container 71 formed using an aluminum alloy. The fuel tank 23 is disposed behind the engine 5 and extends up and down the vehicle, and continues from below the front bulge 72. A lower half bottom 73 extending rearward of the vehicle, and a rear bulge 75 disposed rearward of the front bulge 72 and continuously extending from the lower half bottom 73 toward the rear of the vehicle, Prepare. The front half of the front bulge 72 and the lower half bottom 73 is supported in the vicinity of the rear end of the main frame 17, and the rear half of the lower half bottom 73 and the rear bulge 75 are supported by the seat rail 19.

  The front bulging portion 72 (in FIG. 4, the portion above the two-dot chain line and the front portion of the fuel tank 23) has an outer surface smoothly connected to the rear end portion of the air cleaner box cover 57 that covers the air cleaner box 28. Then, the front bulge portion 72 and the air cleaner box cover 57 are smoothly connected to such an extent that the joint is inconspicuous.

  The lower half bottom portion 73 extends rearward of the vehicle and is buried under the seating seat 59. Further, the lower half bottom portion 73 has a length reaching the rear wheel 13. The lower half bottom portion 73 has a bottom wall 73a that is lowest at a substantially central portion in the front-rear direction.

  The rear bulge portion 75 (in FIG. 4, the portion above the two-dot chain line and the rear portion of the fuel tank 23) extends rearward of the vehicle together with the lower half bottom portion 73 and enters under the seating seat 59. Further, the rear bulge portion 75 has an upper surface wall 75a that is inclined so that the front side of the vehicle is low and becomes high toward the rear.

  The fuel tank 23 includes a pair of left and right front concave portions 77 formed to be disposed in front of the vehicle in a side view, and a pair of left and right rear concave portions 78 formed to be disposed rearward of the center of gravity of the fuel pump 64. Have. Since the center of gravity of the fuel tank 23 formed in an L shape exists on the front bulging portion 72 side, the rear concave portion 78 is disposed behind the center of gravity of the entire fuel pump 64 and the fuel tank 23. Will be.

  The front concave portion 77 is located below the front bulging portion 72 and is formed by denting the side wall 73b of the lower half bottom portion 73.

  The rear concave portion 78 is disposed above the rubber elastic body 69 of the seat rail 19 and is formed by denting the corner portions of the side wall 73b and the bottom wall 73a of the lower half bottom portion 73.

  The fuel pump 64 is accommodated in the fuel tank 23 and supported by the bottom wall 73 a of the lower half bottom portion 73. The fuel pump 64 is provided behind the front bulging portion 72 in a plan view of the vehicle and at a substantially central portion in the front-rear direction of the bottom wall 73a that is the lowest in a side view of the vehicle. Since the center portion of the bottom wall 73a in the front-rear direction is located behind the main frame 17 and the center frame 18, the fuel pump 64 is sufficiently removed from the engine 5 mounted so as to be held in the main frame 17 and the center frame 18. Spaced apart. On the other hand, the fuel pump 64 is disposed in front of the rear wheel 13. The fuel pump 64 supplies gasoline as fuel to a fuel injection device (not shown) provided in the engine 5.

  The front fixing bracket 65 detachably sandwiches the front recess 77 of the fuel tank 23 to support the fuel tank 23 on the main frame 17.

  The intermediate portion fixing bracket 66 supports the fuel tank 23 on the seat rail 19 by detachably sandwiching the starting end portion of the seat rail 19.

  The rubber elastic body 69 is disposed below the rear concave portion 78 of the fuel tank 23 while leaving a gap in the rear concave portion 78.

  The seating seat 59 is disposed above the lower half bottom portion 73 and is integrally fixed to the fuel tank 23 via the seat cowl 58.

  The suspension unit 52 also functions as a heat shield that shields the fuel pump 64 from the radiant heat of the engine 5. The suspension unit 52 is connected to the vehicle body frame 2 via a suspension bracket 79 provided at the rear end portion of the main frame 17 or the upper end portion of the center frame 18.

  The seat rail 19 is a frame that extends from the front end connected to the rear end portion of the main frame 17 to the rear end that sandwiches the fuel pump 64 in plan view of the vehicle.

  The seat cowl 58 is fixed to the fuel tank 23 and covers the upper wall 75a and the side wall 73b and extends rearward of the vehicle.

The bottom cover 61 is fixed to the fuel tank 23 and covers the bottom wall 73a and the side wall 73b. The bottom cover 61 shields the fuel pump 64 approaching the engine exhaust system 26 such as the exhaust pipe 29 and the muffler 31 from these radiant heats when the lower half bottom portion 73 of the fuel tank 23 sinks below the seating seat 59. Generation of bubbles in the fuel pump 64 is prevented. The bottom cover 61 also has a function of protecting the fuel pump 64 from mud and sand that the rear wheel 13 jumps up.
FIG. 6 is a side view showing the fuel tank according to the embodiment of the present invention.
FIG. 7 is a longitudinal sectional view showing a fuel tank according to an embodiment of the present invention.
FIG. 8 is a perspective view showing a fuel tank according to an embodiment of the present invention.

  As shown in FIGS. 6 to 8, the fuel tank 23 includes a front bulging portion 72 (first bulging portion), a rear bulging portion 75 (second bulging portion), and a bulging portion that protrude upward. A container 71 having a trough 81 between 72 and 75 and an oil supply port structure 82 provided in the front bulge 72, one open end 83 a disposed in the front bulge 72, and the rear bulge 75. And a vent pipe portion 83 having the other opening end 83b disposed in the upper portion and communicating with the inside of the front bulge portion 72 and the inside of the rear bulge portion 75. In other words, the fuel tank 23 includes a fuel filler structure 82 provided in the front bulge portion 72, one open end 83 a disposed in the front bulge portion 72, and the vicinity of the upper rear end in the rear bulge portion 75. And a vent pipe portion 83 having the other opening end 83b disposed in the upper portion and communicating with the inside of the front bulge portion 72 and the inside of the rear bulge portion 75.

  In addition, the fuel tank 23 includes an open pipe 85 that leads the air into the fuel tank 23 by communicating the top of the front bulge 72 and the outside of the fuel tank 23.

  In addition to the front recess 77 and the rear recess 78, the fuel tank 23 includes seat cowl fastening portions 86 and 87 for fixing the seat cowl 58 to the fuel tank 23, and bottom cover fastening for fixing the bottom cover 61 to the fuel tank 23. Parts 88 and 89.

  The fuel filler structure 82 is provided at the top of the front bulging portion 72 and communicates the inside and outside of the fuel tank 23 and is used to guide gasoline as fuel into the fuel tank 23. The oil filler structure 82 includes an oil filler 91 opened at the top of the front bulging portion 72 and an oil filler lid 92 that detachably closes the oil filler 91.

  The vent pipe portion 83 is accommodated in the container 71 and is fixed to the upper surface wall 75 a of the rear bulge portion 75. The other open end 83b of the vent pipe 83 is disposed in the vicinity of the top in the rear bulge 75, and one open end 83a is disposed higher than the other open end 83b. The vent pipe portion 83 is connected to the small container 93 (second container) that divides a space having one open end 83a upward, and the other open end 83b while being connected to the bottom surface 93a of the small container 93. And a communication pipe 95.

  The small container 93 is disposed at a position higher than the other opening end 83b (two-dot chain line in FIG. 7). The small container 93 has an internal volume larger than the internal volume of the vent pipe portion 83. The small container 93 is disposed so as to be separated in the horizontal direction so that the fuel guided into the fuel tank 23 from the fuel filler port 91 is not poured directly.

  The communication pipe 95 extends from the open end 83b disposed in the vicinity of the rear end upper portion, which is the top portion in the rear bulge portion 75, to the inside of the valley portion 81 along the inner surface of the upper surface wall 75a. Connected to the bottom surface 93 a of the container 93.

  The open tube 85 has one open end 85 a opened at the top of the front bulge portion 72 and the other open end 85 b opened toward the front of the lower half bottom portion 73.

  A pair of seat cowl fastening portions 86 and 87 and bottom cover fastening portions 88 and 89 are provided on the left and right, respectively.

  The seat cowl fastening portion 86 is disposed near the lower portion of the front bulging portion 72 of the fuel tank 23 and fixes the front side of the seat cowl 58. On the other hand, the seat cowl fastening portion 87 is disposed near the rear end of the lower half bottom portion 73 of the fuel tank 23 and fixes the rear side of the seat cowl 58.

  The bottom cover fastening portion 88 is disposed above the intermediate portion fixing bracket 66 and fixes the front side of the bottom cover 61. On the other hand, the bottom cover fastening portion 89 is disposed near the rear end of the lower half bottom portion 73 and fixes the rear side of the bottom cover 61.

  The bottom wall 73 a of the fuel tank 23 has a supply port 97 communicated with the fuel pump 64.

  The manner in which gasoline as fuel is filled in the fuel tank structure 22 and the fuel tank 23 of the motorcycle 1 configured as described above will be described.

  9 and 10 are views showing the state of the fuel filled in the fuel tank according to the embodiment of the present invention.

  FIG. 10 is a view showing a state of fuel filled in the fuel tank according to the embodiment of the present invention.

  As shown in FIG. 9, the fuel poured into the fuel tank 23 from the fuel filler port 91 first fills from the bottom side of the lower half bottom 73 to the height of the valley 81 while maintaining a substantially uniform liquid level (in FIG. 9). The two-dot chain line A). Thereafter, the fuel poured into the fuel tank 23 gradually fills the front bulging portion 72 and pushes the vent pipe portion 83 into the front bulging portion 72 through the air in the rear bulging portion 75. The inside of the exit 75 is gradually filled. When the fuel level reaches the other open end 83 b in the rear bulge 75 arranged at the top of the rear bulge 75, the fuel flows into the communication pipe 95 of the vent pipe 83 and is swelled rearward. The inside of the protruding portion 75 is substantially filled (two-dot chain line B in FIG. 9). Thereafter, the fuel is stored in the fuel tank 23 while further filling the front bulging portion 72 (two-dot chain line C in FIG. 9). At this time, the fuel is also poured into the inside of the small container 93 of the vent pipe portion 83.

  Thereafter, as shown in FIG. 10, when the fuel is used and the fuel tank 23 becomes almost empty, the fuel remains in the communication pipe 95 (hatching D in FIG. 10). On the other hand, the fuel that has filled the inside of the small container 93 is discharged from the other open end 83 b of the vent pipe portion 83.

  When the fuel is poured again into the fuel tank 23 from this state, the fuel poured into the fuel tank 23 from the fuel filler port 91 firstly maintains the substantially uniform liquid level from the bottom side of the lower half bottom portion 73 to the valley portion 81. It fills up to the height (two-dot chain line A in FIG. 10). Thereafter, the fuel poured into the fuel tank 23 gradually fills the front bulge portion 72. On the other hand, the fuel remaining in the communication pipe 95 prevents the air in the rear bulge part 75 from being exhausted to the front bulge part 72 through the vent pipe part 83, so that the air is trapped in the rear bulge part 75. It is done. Thereafter, the fuel poured into the fuel tank 23 further fills the front bulging portion 72 and exceeds the bottom surface 93a of the small container 93 (two-dot chain line E in FIG. 10). At this time, the air in the rear bulge portion 75 receives a differential pressure due to the difference (water head difference) between the liquid level in the front bulge portion 72 and the liquid level in the rear bulge portion 75. The fuel is pushed out into the small container 93 (two-dot chain line F in FIG. 10) and escapes into the front bulging portion 72. Thus, the fuel gradually fills the rear bulge 75 while pushing the air in the rear bulge 75 into the front bulge 72 through the vent pipe 83. When the fuel level reaches the other open end 83 b in the rear bulge 75 arranged at the top of the rear bulge 75, the fuel flows into the communication pipe 95 of the vent pipe 83 and is swelled rearward. The inside of the protruding portion 75 is substantially filled (two-dot chain line B in FIG. 10). Thereafter, the fuel is stored in the fuel tank 23 while further filling the front bulging portion 72 (two-dot chain line C in FIG. 10). At this time, the fuel is also poured into the inside of the small container 93 of the vent pipe portion 83.

  In addition, the fuel can be more easily filled in the rear bulge portion 75 by filling the fuel tank 23 while pressurizing the fuel.

  According to the fuel tank structure 22 and the fuel tank 23 of the motorcycle 1 according to the present embodiment, the ratio of the fuel filling amount to the internal volume of the fuel tank 23 by extracting the air in the rear bulging portion 75 from the vent pipe portion 83. Can be increased.

  Further, according to the fuel tank structure 22 and the fuel tank 23 of the motorcycle 1 according to the present embodiment, the fuel having a complicated shape having a plurality of bulging portions (the front bulging portion 72 and the rear bulging portion 75). Even in the case of the tank 23, the ratio of the fuel filling amount to the internal volume can be increased, so that the shape of the fuel tank 23 can be set to a degree of freedom. That is, since the fuel tank 23 has a shape corresponding to the vehicle shape, the internal volume can be expanded as much as possible by effectively utilizing the space of the installation location, and the expanded internal volume can be effectively utilized.

  Furthermore, according to the fuel tank structure 22 and the fuel tank 23 of the motorcycle 1 according to this embodiment, even if the fuel is filled in the vent pipe portion 83, a plurality of bulge portions (the front bulge portion 72, the rear bulge portion 72, The ventilation of the ventilation pipe portion 83 can be recovered by the difference in liquid level between the bulging portions 75) (water head difference). That is, the fuel tank 23 can reliably maintain a high ratio of the fuel filling amount to its internal volume even when the fuel is refilled. Further, as a result, the fuel tank 23 minimizes the decrease in the fuel filling amount of the fuel tank 23 by the vent pipe portion 83.

  Furthermore, according to the fuel tank structure 22 and the fuel tank 23 of the motorcycle 1 according to the present embodiment, the liquid level in the fuel tank 23 is reduced by disposing the small container 93 at a position higher than the communication pipe 95. Since the fuel filled in the small container 93 can be discharged via the communication pipe 95 in accordance with the decrease, the integral fuel of the small container 93 can be supplied to the engine 5 without waste.

  According to the fuel tank structure 22 of the motorcycle 1 according to the present embodiment, the seating seat 59 is provided to be tilted forward, and the seating position of the occupant of the motorcycle 1 is naturally closer to the front of the seating seat 59. That is, it approaches the engine 5 side. In general, since the center of gravity of the motorcycle 1 is in the vicinity of the engine 5, the mobility of the vehicle can be improved by bringing the seating position of the passenger closer to the engine 5.

  Therefore, according to the fuel tank structure 22 and the fuel tank 23 of the motorcycle 1 according to the present embodiment, these are provided with a plurality of bulging portions (front bulging portion 72 and rear bulging portion 75) protruding upward. The ratio of the fuel filling amount to the internal volume can be increased by appropriately exhausting air from the bulging portions (the front bulging portion 72 and the rear bulging portion 75).

  The vehicle on which the fuel tank 23 is mounted is not limited to the motorcycle 1. For example, in the case of an automobile, the fuel tank 23 can arrange a plurality of bulging portions while avoiding the chassis to effectively use the space of the installation location and secure a larger internal volume.

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 5 Engine 5a Cylinder assembly 5b Crank assembly 6 Steering mechanism 8 Front wheel 9 Steering mechanism 11 Front wheel suspension device 12 Swing arm 13 Rear wheel 15 Rear wheel suspension device 16 Head pipe 17 Main frame 18 Center frame 19 Seat rail 21 Pivot shaft 22 Fuel tank structure 23 Fuel tank 25 Engine intake system 26 Engine exhaust system 27 Throttle body 28 Air cleaner box 29 Exhaust pipe 31 Muffler 33 Steering head 34 Front fork 35 Handlebar 36 Handle grip 37 Throttle grip 41 Front wheel axle 42 Front wheel 43 Front wheel tire 45 Front wheel brake plate 47 Rear wheel axle 48 Rear wheel wheel 49 Rear wheel tire 50 Spring 51 Sucker absorber 52 Suspension unit 53 Cowling 55 Front cover 56 Side cover 57 Air cleaner box cover 58 Seat cowl 59 Seating seat 61 Bottom cover 64 Fuel pump 65 Front fixing bracket 66 Intermediate fixing bracket 67 Front fastening member 68 Rear fastening member 69 Rubber elastic body 71 Container 72 Front bulging portion 73 Lower half bottom portion 73a Bottom wall 73b Side wall 75 Rear bulging portion 75a Upper surface wall 77 Front recessed portion 78 Rear recessed portion 79 Suspension bracket 81 Valley portion 82 Filling port structure 83 Vent pipe portion 83a Opening End 83b Open end 85 Open pipe 85a Open end 85b Open end 86, 87 Seat cowl fastening portion 88, 89 Bottom cover fastening portion 91 Refueling port 92 Refueling port lid 93 Small container 93a Bottom surface 95 Communication tube 97 Feeding port

Claims (7)

A container having a first bulging portion protruding upward, a second bulging portion, a valley between the bulging portions, and a fuel filler structure provided in the first bulging portion;
The first bulge and the second bulge having one open end disposed in the first bulge and the other open end disposed in the second bulge A fuel tank comprising: a vent pipe portion that communicates with the fuel tank. The fuel tank according to claim 1, wherein the vent pipe portion is accommodated in the container. The said other opening end is arrange | positioned in the top vicinity in said 2nd bulging part, and said one opening end is arrange | positioned higher than said other opening end, The Claim 1 or 2 characterized by the above-mentioned. Fuel tank. The vent pipe part is a second container that divides a space having the one open end upward, a communication pipe that is connected to the bottom surface of the second container and has the other open end, The fuel tank according to claim 1, further comprising: 5. The fuel tank according to claim 4, wherein the other opening end is disposed in the vicinity of a top portion in the second bulging portion, and the second container is disposed higher than the other opening end. . 6. The fuel tank according to claim 4, wherein an inner volume of the second container is larger than an inner volume of the vent pipe portion. A pair of left and right mainframes extending in front and rear of the vehicle;
An engine mounted on the lower side of the main frame;
A fuel tank formed in a substantially L shape in a side view of the vehicle;
A seat seat held in the fuel tank,
The fuel tank is
A front bulge disposed behind the engine and extending up and down the vehicle;
A lower half bottom portion that extends continuously from below the front bulge portion and extends rearward of the vehicle;
A rear bulge portion disposed rearward of the front bulge portion and extending upwardly toward the rear of the vehicle continuously from the lower half bottom portion;
A fuel filler structure provided in the front bulge,
The front bulge and the rear bulge are communicated with one open end disposed in the front bulge and the other open end disposed in the vicinity of the upper rear end in the rear bulge. A vent pipe part to be
The fuel tank structure for a motorcycle, wherein the seat is disposed above the rear bulge portion.

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