JP2008238904A - Fuel tank of motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel tank of a motorcycle capable of preventing temperature of fuel from rising due to the heat radiated from an engine. <P>SOLUTION: In this motorcycle provided with the engine 19 between the front wheel 2 and the rear wheel 25 and the fuel tank 21 above the engine 19, the fuel tank 21 is constituted by joining an upper tank 110 to a lower tank 120 which are made of resin, and a foaming part 122 molded by resin foaming molding is molded integrally with the lower tank 120 in a part of the lower tank 120 being the part facing the engine 19. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel tank for a motorcycle including a fuel tank formed of a resin material.

  In a motorcycle or the like, a fuel tank formed of a resin material is known. Such resin material molding methods currently include blow molding, injection molding, rotational molding, and the like. In a fuel tank of an automobile or the like, it is possible to keep the manufacturing cost low by integrally molding the entire fuel tank. Blow molding is often used. On the other hand, in blow molding, it is difficult to make the plate thickness of the wall portion of the fuel tank thin or uniform, so that injection molding is also considered (for example, see Patent Document 1).

On the other hand, as an injection molded product, a resin foam molded product obtained by foaming a polyamide resin used for molding is known. According to this technique, the molded product can be further reduced in weight (for example, see Patent Document 2).
JP 2004-98886 A JP 2006-8952 A

  In a motorcycle, a fuel tank is often disposed above the engine. For this reason, the heat released from the engine during traveling may heat the lower side of the fuel tank, and this heat may increase the fuel temperature in the fuel tank.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a fuel tank for a motorcycle in which it is difficult to raise the fuel temperature by heat released from the engine.

In the present invention, a motorcycle is provided with an engine between a front wheel and a rear wheel, and a fuel tank is provided above the engine, and the fuel tank is configured by joining a resin upper tank and a lower tank, A foamed portion formed by resin foam molding is formed integrally with the lower tank at a part of the lower tank facing the engine.
According to this configuration, the heat released from the engine is blocked by the foamed portion, and the heat is not easily transmitted to the fuel.

The engine includes a cylinder extending upward from the crankcase, an intake box above the cylinder, a fuel tank disposed behind the intake box and above the crankcase, and a joint surface between the upper tank and the lower tank serving as a fuel. The front portion can be made higher than the rear portion of the tank so that the intake box, the crankcase, and the lower tank face each other.
According to this configuration, even if the engine that dissipates heat and the fuel tank are arranged to face each other, the foamed portion blocks heat, so that heat is hardly transmitted to the fuel.

According to the present invention, the fuel tank is configured by joining a resin upper tank and a lower tank, and a foamed part formed by resin foam molding is formed on a part of the lower tank facing the engine by the lower tank. Since it is integrally molded, the heat released from the engine is blocked by the foamed portion, making it difficult to transfer the heat to the fuel. Therefore, it is possible to make it difficult for the temperature of the fuel to rise.
In addition, since the foamed portion is formed integrally with the lower tank, the influence of heat on the fuel in the fuel tank can be mitigated without providing additional parts for blocking heat. Thereby, the cost increase by the increase in the number of parts can be avoided.

  The engine includes a cylinder extending upward from the crankcase, an intake box above the cylinder, a fuel tank disposed behind the intake box and above the crankcase, and a joint surface between the upper tank and the lower tank serving as a fuel. The front part is made higher than the rear part of the tank so that the intake box, crankcase, and lower tank face each other, so even if the engine that dissipates heat and the lower tank of the fuel tank are placed facing each other, the foamed part By blocking the heat, it becomes difficult for the heat to be transferred to the fuel in the fuel tank. Therefore, the arrangement of the engine and the fuel tank can be determined without much considering the influence of heat, and the degree of freedom in design is improved.

  Hereinafter, a fuel tank of a motorcycle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a motorcycle equipped with a fuel tank according to a first embodiment of the present invention. In the following description, the vertical direction and the front-rear direction indicate directions based on FIG. 1, and the left-right direction indicates a direction viewed from the driver.

  As shown in FIG. 1, the motorcycle 1 includes a vehicle body frame 6, which includes a head pipe 61, a pair of left and right main frames 62 extending obliquely rearward and downward from the head pipe 61, and these A pair of left and right pivot plates 63 connected to the rear of the main frame 62 and a cross member (not shown) that horizontally connects the pivot plates 63 to each other.

  As shown in FIG. 1, the front fork 3 is swingably connected to the head pipe 61 of the vehicle body frame 6. A front wheel 2 having a hydraulic disc brake is rotatably supported at a lower end portion of the front fork 3, and a front fender 20 is provided above the front wheel 2. The front fender 20 is attached in a manner supported by the front fork 3. A steering handle 5 is attached to the upper end of the front fork 3.

  As shown in FIG. 1, a water-cooled in-line four-cylinder horizontal type engine 19 is mounted below the center portion of the body frame 6. The engine 19 includes a cylinder 14 that extends upward from the crankcase. A middle cowl 8 is provided on both the left and right sides of the engine 19, and the middle cowl 8 is detachably attached to the vehicle body in a manner continuous with the upper cowl 7. The upper cowl 7 is provided with a two-lamp headlight 28, a wind screen 29, a pair of left and right front blinkers 27, and a pair of left and right rearview mirrors 30.

  A lower cowl 9 is attached below the engine 19. The lower cowl 9 is detachably attached to the vehicle body in a manner continuous with the middle cowl 8. A fuel tank 21 is placed above the engine 19 and above the vehicle body frame 6, and the fuel tank 21 is entirely covered with a fuel tank cover 24. A rear seat 51 (pillion seat) is mounted behind the front seat 22, and a rear cowl 41 and a rear fender 42 are attached to the lower side of the rear seat 51. A stop lamp 43 and a pair of left and right rear winkers 44 are attached to the rear fender 42.

  On the other hand, as shown in FIG. 1, a swing arm 23 (rear fork) is swingably supported at the lower rear part of the body frame 6, and a hydraulic disc brake is attached to the rear end of the swing arm 23. The provided chain drive type rear wheel 25 is rotatably supported below the rear fender 42.

  FIG. 2 is an enlarged view of a mounting portion of the fuel tank 21 shown in FIG. FIG. 3 is an exploded perspective view of the fuel tank cover 24 covering the fuel tank 21 with the fuel tank cover 24 removed, as viewed from the rear left side.

  An intake box 72 is disposed on the front side of the fuel tank 21 and above the cylinder 14 (see FIG. 1) extending upward from the crankcase of the engine 19. The fuel tank 21 and the intake box 72 are covered with a fuel tank cover 24 shown in FIGS. As shown in FIG. 3, the fuel tank cover 24 is fastened to the vehicle body side from the outside of the fuel tank cover 24 by a plurality of mounting bolts 13 and a grommet (not shown). By removing the mounting bolts 13 and the like, The fuel tank cover 24 can be removed from the main body side of the motorcycle.

  The intake box 72 takes in traveling wind from an intake port 73 (see FIG. 1) located on the front side of the vehicle body, and supplies air purified by a filter to a throttle body (not shown) disposed near the intake box 72. It is supposed to be. As described above, the motorcycle 1 has the intake box 72 disposed on the front side of the fuel tank 21 so that the intake box 72, the throttle body, and the intake port are arranged substantially linearly. High efficiency is realized.

A fuel pump 70 for discharging the fuel in the fuel tank 21 is attached inside the fuel tank 21. The fuel pump 70 includes a discharge portion 70d outside the fuel tank 21. Fuel discharged from the discharge portion 70d is sent to a throttle body (not shown) via a fuel pipe 90. ing.
In FIG. 2, a fuel pump 70 includes a pump 70a for sending fuel to the outside of the fuel tank 21, a filter 70b for filtering the fuel, and a float switch 70c for detecting the remaining amount of fuel in the fuel tank 21. Etc.

Further, the fuel tank 21 is pivotally supported on the main body side so that the front portion of the fuel tank 21 can be turned upward about the swing shaft 71 shown in FIG. As a result, the fuel tank cover 24 is removed and rotated toward the upper front of the fuel tank 21 to secure a maintenance space for checking the intake box 72, adjusting the fuel pump 70, and the like. It can be done.
In FIG. 3, 11 is a top bridge, and 12 is a head pipe.

4 is an exploded perspective view showing a state in which the fuel tank is removed from the state of FIG.
The fuel tank 21 is attached by a mount bolt 15 that is detachable from the outside of the vehicle body frame 6. As shown in FIG. 4, a crankcase of the engine 19 is disposed below the fuel tank 21. That is, the bottom of the fuel tank 21 and the intake box 72 and the crankcase of the engine 19 are arranged so as to face each other with a predetermined gap therebetween. Therefore, the heat of the traveling engine 19 is released (transmitted) to the bottom of the fuel tank 21 located at the top of the engine 19.

FIG. 5 is a side view showing the fuel tank 21 as a single unit. In FIG. 4, the left side is the front of the vehicle body.
The fuel tank 21 is divided into two parts, an upper tank 110 and a lower tank 120. In FIG. 5, the fuel tank 21 is joined at joints 100 extending from the upper left side (front upper side of the vehicle body) to the lower right side (lower rear side of the vehicle body). Has been.
The upper tank 110 and the lower tank 120 are each formed by injection molding.

  The upper tank 110 has an arm shape that is recessed from the joint portion 100 toward the obliquely upper rear side of the vehicle body. The upper tank 110 has a fuel supply port 111 formed on the upper side thereof, and mounting portions 21a and 112 for fixing the fuel tank 21 to the vehicle body side are provided below the upper tank 110 at the rear of the vehicle body. Yes. Further, a flange portion 113 for joining with a flange portion 123 (details will be described later) of the lower tank 120 is continuously provided in the circumferential direction of the split opening portion at the edge portion of the split opening portion constituting the joint portion 100. Is provided. The upper tank 110 is configured such that the mold for injection molding is divided into two in the vertical direction in FIG. 5 so that the shape of the fuel supply port 111 is formed by injection molding.

  The lower tank 120 has an arm shape that is recessed downward from the joint portion 100. The lower tank 120 has an opening 121 to which the fuel pump 70 is attached at the bottom 120a. A flange portion 123 for joining with the flange portion 113 of the upper tank 110 is provided continuously in the circumferential direction of the split opening portion at the edge portion of the split opening portion for constituting the joint portion 100. Further, with respect to the lower tank 120, the injection mold is divided into two in the vertical direction in FIG.

A foamed portion 122 formed by resin foam molding is formed around the opening 121 of the lower tank 120 and in a portion facing the engine 19. In this foam part 122, the wall plate is thicker than the wall part of the other part by foaming the resin material, and the heat passing through the wall part is blocked by this thick wall part and the internal space. can do.
The portion facing the engine 19 is a portion where the crankcase of the engine 19 and the outer surface of the fuel tank face each other with a space (gap) therebetween, but other portions that do not face the crankcase of the engine 19 directly. However, since it is affected by the heat from the crankcase of the engine 19, it also includes a portion where it is preferable to take some measures to block the heat.

  Here, the resin foam molding is a molding method in which a porous body is formed by forming bubbles with a foaming agent added from the outside when molding a molding material or released from the molding material. As the foaming agent, there are chemical foaming agents (famous for baking soda, citric acid, ADCA, etc.) that decompose by heat, and physical foaming agents (water, butane, etc.) that vaporize depending on the temperature during molding.

  In this resin foam molding, a part of a molded product can be foamed by various methods. For example, there is a gas assist injection molding method. This molding method involves injecting a foamed resin into a counterpressure mold cavity in which pressure is maintained in a pressurized state by a stylus, and then injecting pressurized gas to form a hollow pair once before the resin cools. The gas in the hollow part is discharged to foam the resin toward the hollow part. This method utilizes the phenomenon that the gas to be injected gathers at the center of the thick part with little resistance, and can be applied to a thin molded product.

There is also a GAIM molding method. In this molding method, molten resin and high-pressure gas are injected into the mold, and the molten resin is cooled while shaping and holding with this gas pressure. After cooling is complete, the gas is released or recovered from the molded product. It is a method of releasing. According to this method, the foamed portion 122 can be formed by selectively flowing a gas body through the thin-walled portion.
Furthermore, there is a short shot method that is most frequently used. This molding method is the simplest molding, in which a foamable resin containing a foam material and a core material is injected in an amount insufficient to fill the mold cavity, and the foam cavity fills the mold cavity. Is the method.

The resin materials used for the upper tank 110 and the lower tank 120 are various resin materials having low gas permeability and excellent heat resistance that are not easily affected by heat convection from the engine 19, and are foamable. Good materials such as polyamide resin can be used.
Representative examples of the main components of the polyamide resin include, for example, amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, ε-caprolactam, ω-laurolactam, and the like. Lactam, tetramethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexa Methylenediamine, 5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3- Aminomethyl-3,5,5-to Limethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine, etc. Aliphatic, cycloaliphatic, aromatic diamines, and adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5- Aliphatic, alicyclic and aromatic dicarboxylic acids such as methyl isophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and the like can be mentioned. In the present invention, these are derived from these raw materials. Each polyamide homopolymer or copolymer It can be used in the form of mixtures.

  On the other hand, the upper tank 110 and the lower tank 120 are joined firmly over the entire circumference of the flange portions 113 and 123 after the flange portion 113 of the upper tank 110 and the flange portion 123 of the lower tank 120 are overlapped. In this joining, for example, the joining surfaces may be melted and directly joined, or a molten resin may be injected therebetween to join.

  According to the fuel tank of the motorcycle according to the embodiment of the present invention, the fuel tank 21 is formed by joining the resin upper tank 110 and the lower tank 120, and is a part of the lower tank 120 that faces the engine 19. Since the foamed part 122 formed by resin foam molding is integrally formed with the lower tank 120, the heat released from the engine 19 is blocked by the foamed part 122, making it difficult for heat to be transferred to the fuel. Therefore, it is possible to make it difficult for the temperature of the fuel to rise.

  Moreover, since the foaming part 122 is integrally molded, the influence of heat on the fuel in the fuel tank 21 can be mitigated without providing additional parts for blocking heat. Thereby, the cost increase by the increase in the number of parts can be avoided.

  The engine 19 further includes a cylinder 14 extending upward from the crankcase, an intake box 72 above the cylinder 14, a fuel tank 21 disposed above the crankcase behind the intake box 72, and an upper tank 110 and a lower tank Since the front portion of the joint portion 100 of the 120 is made higher than the rear portion of the fuel tank so that the intake box 72, the crankcase of the engine 19 and the lower tank 120 face each other, the heat dissipation of the engine 19 and the fuel tank 21 Even if the lower tank 120 is disposed so as to face the lower tank 120, the foamed portion 122 blocks the heat, so that the heat is hardly transmitted to the fuel in the fuel tank 21. Therefore, the arrangement of the engine 19 and the fuel tank 21 can be determined without much consideration of the influence of heat, and the degree of freedom in design is improved.

While the embodiments of the present invention have been described above, various modifications and changes can be made based on the technical idea of the present invention.
In the present embodiment, the foamed part 122 is formed around the opening of the lower tank 120 and in a part of the part facing the engine 19, but the wall of the lower tank 120 is formed by foaming the entire lower tank 120. The entire film may be formed thick. Thereby, weight reduction of the lower tank 120 whole can be achieved. Further, similarly to the effect of the present application, it is possible to block the influence of heat released from the crankcase of the engine 19 and to make it difficult to raise the temperature of the fuel in the fuel tank 21.

  Further, not only the lower tank 120 but also a part of the upper tank 110, for example, a part where the driver is in contact with the fuel tank 21 and a part which receives direct sunlight can be foam-molded. Accordingly, the heat received from the fuel tank 21 by the driver can be cut off without providing the fuel tank cover and covering the outside of the fuel tank. In addition, the fuel in the fuel tank can be made difficult to be warmed by direct sunlight.

  Furthermore, when the rigidity of the fuel tank 21 is sufficient, the inside of the foamed portion 122 can be made hollow by a gas assist injection molding method. That is, the inside is made hollow by releasing the gas after cooling the resin in the mold. Thereby, heat can be cut off at the hollow portion to make it difficult for the fuel in the fuel tank 21 to be warmed, and the fuel tank 21 can be further reduced in weight.

1 is a side view of a motorcycle equipped with a fuel tank according to a first embodiment of the present invention. It is an enlarged view of the part to which the fuel tank of FIG. 1 is attached. It is a disassembled perspective view which shows the state which decomposed | disassembled the fuel tank cover from the main body side. FIG. 4 is an exploded perspective view showing a state where the fuel tank is removed from FIG. 3. It is a side view of a fuel tank simple substance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Front wheel 6 Body frame 14 Cylinder 19 Engine 21 Fuel tank 24 Fuel tank cover 25 Rear wheel 62 Main frame 70 Fuel pump 72 Intake box 73 Inlet 100 Joint (joint surface)
110 Upper tank 111 Fuel supply port 113, 123 Flange part 120 Lower tank 121 Opening part 122 Foaming part

Claims (2)

A motorcycle having an engine between a front wheel and a rear wheel, and a fuel tank above the engine,
The fuel tank is formed by joining a resin upper tank and a lower tank, and a foamed part formed by resin foam molding is formed integrally with the lower tank at a part of the lower tank facing the engine. A motorcycle fuel tank.   The engine includes a cylinder extending upward from a crankcase, an intake box is provided above the cylinder, a fuel tank is disposed above the crankcase behind the intake box, and a joint surface between the upper tank and the lower tank is connected to the fuel tank. The fuel tank for a motorcycle according to claim 1, wherein a front portion is made higher than a rear portion so that the intake box, the crankcase, and the lower tank face each other.

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