JP2008201171A - Fuel tank and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a favorable external appearance of a vehicle even when an exposed material portion is exposed on the external appearance of the vehicle in a metallic fuel tank with an oil supply port cylinder body welded to a tank body. <P>SOLUTION: The oil supply port cylinder body 41 is provided with an extension part 43 entering the tank. The tank body 32 is provided with an insertion port 36 for inserting the extension part 43 therein, and a tank inner cylinder part 37 extending from a peripheral edge of the insertion port 36 to the inside of the tank along the extension part 43. The extension part 43 is welded to the tank inner cylinder part 37 on the inside of the tank. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metal fuel tank and a method for manufacturing the fuel tank.

Conventionally, the fuel tank has a structure in which a fuel filler cylinder is welded to the tank body (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 08-197967

By the way, some recent fuel tanks are made of a light metal material such as an aluminum alloy or a titanium alloy, have a material exposed portion on the outer surface thereof, and expose the material exposed portion to the vehicle exterior. In the case of such a fuel tank, if there is a weld mark when the fuel filler cylinder is welded to the tank body on the outer surface of the tank, the appearance of the vehicle is impaired, and there is a demand for improvement of such a point. Yes.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to maintain a good appearance of a vehicle even when a material exposed portion is exposed to the exterior of a vehicle in a metal fuel tank in which a fuel filler cylinder is welded to a tank body.

  As a means for solving the above-mentioned problems, the invention described in claim 1 is to weld a metal tank main body (for example, the tank main body 32 of the embodiment) and a fuel filler cylinder (for example, the fuel filler cylinder 41 of the embodiment) by welding. In an integrally coupled fuel tank (for example, fuel tank 31 of the embodiment), an extension portion (for example, an extension portion 43 of the embodiment) that enters the tank inside the fuel filler cylinder is provided, and the tank main body has the above-mentioned An insertion port (for example, the insertion port 36 of the embodiment) through which the extension portion is inserted and a tank inner cylinder portion (for example, the tank inner cylinder portion 37 of the embodiment) extending from the periphery of the insertion port to the inside of the tank along the extension portion are provided. The extension part and the tank inner cylinder part are welded inside the tank.

  According to a second aspect of the present invention, a seam roller (for example, the seam rollers R1 and R2 in the embodiment) is brought into contact with the inner peripheral surface of the extension portion and the outer peripheral surface of the tank inner cylinder portion, respectively. It is characterized by seam welding the tube portion.

  The invention described in claim 3 is a fuel formed by integrally joining a metal tank body (for example, the tank body 32 of the embodiment) and a fuel filler cylinder (for example, the fuel filler cylinder 41 of the embodiment) by welding. In the manufacturing method of the tank (for example, the fuel tank 31 of the embodiment), an extension portion (for example, the extension portion 43 of the embodiment) that enters the tank inside the tank is provided in the fuel filler cylinder, and the extension portion is inserted into the tank body An insertion port (for example, the insertion port 36 of the embodiment) to be made and a tank inner cylinder portion (for example, the tank inner cylinder portion 37 of the embodiment) extending from the periphery of the insertion port to the inside of the tank along the extension portion are provided. A relatively small-diameter seam roller (for example, the seam roller R2 of the embodiment) is brought into contact with the inner peripheral surface of the tank, and a relatively large-diameter seam roller (for example, the seam roller R1 of the embodiment) is disposed on the outer peripheral surface of the tank inner cylinder portion. The are brought into contact, and the extension portion and the tank inner cylindrical portion, characterized in that the seam weld.

  According to the first and second aspects of the present invention, even if a welding mark is generated at the welded portion between the tank main body and the fuel filler cylinder, the welding mark is not exposed to the outer surface of the tank by being located inside the tank. Therefore, even when there is a material exposed portion on the outer surface of the tank and the material exposed portion is exposed to the vehicle exterior, the appearance of the vehicle can be kept good.

  According to the third aspect of the present invention, it is possible to easily arrange the seam roller on the inner peripheral side of the extension portion which tends to be narrower than the outer peripheral side of the tank inner cylindrical portion, thereby improving workability.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the directions such as front, rear, left and right in the following description are the same as those in the vehicle unless otherwise specified. In the figure, an arrow FR indicates the front of the vehicle, and an arrow UP indicates the upper side of the vehicle.

  In the off-road type motorcycle (vehicle) 1 shown in FIG. 1, the front wheel 2 is pivotally supported on the lower ends of the left and right front forks 3, and the upper part of the left and right front forks 3 is connected to the head of the vehicle body frame 5 via the steering stem 4. The pipe 6 is pivotally supported so as to be steerable. A bar-type steering handle 7 is attached to the upper portion of the steering stem 4.

  The left and right main tubes 8 extend rearward and rearward from the upper rear side of the head pipe 6, and the rear ends of the left and right main tubes 8 are connected to the upper ends of the left and right pivot frames 9 at the vehicle front and rear intermediate portions. The left and right main tubes 8 branch from the head pipe 6 to the left and right and extend rearward and obliquely rearwardly, and a rear portion extending rearward substantially parallel to the center plane of the vehicle body is integrally connected via a gently curved portion. It is provided linearly in a side view.

  A single down frame 11 having a steeper slope than the left and right main tubes 8 extends obliquely rearward and downward from the lower rear side of the head pipe 6, and a right and left lower slope having the same inclination is formed from the lower end of the down frame 11. The frame 12 branches and extends to the left and right, and the lower part of the left and right lower frame 12 curves backward and extends to connect to the lower end of the left and right pivot frame 9. That is, the body frame 5 constitutes a twin spar type cradle frame, and an engine 21 that is a prime mover of the motorcycle 1 is mounted inside the body frame 5. In addition, the code | symbol 13 in a figure shows the gusset frame which branches to right and left from the up-and-down intermediate part rear side of the down frame 11, is extended back, and is connected to the front-and-rear intermediate part lower side of the left and right main tubes 8.

  A front end portion (base end portion) of the swing arm 15 is pivotally supported at the lower portion of the left and right pivot frames 9 so as to be swingable up and down. A rear wheel 17 of the motorcycle 1 is mounted on a rear end portion of the left and right rear arms 16 of the swing arm 15. Is supported. A lower member of the rear cushion unit 19 is connected to the lower side of the front portion of the swing arm 15 via a link mechanism 18, and the upper member of the rear cushion unit 19 extends between the vicinity of the rear ends of the left and right main tubes 8. 14.

  The engine 21 is a single-cylinder engine having a crankshaft parallel to the vehicle width direction, and a cylinder 23 is erected substantially vertically on a crankcase 22 constituting the lower part thereof. The rear part of the crankcase 22 also serves as a transmission case. A drive sprocket 24 is arranged on the left side of the rear part of the crankcase 22, and a drive chain 26 is wound around the drive sprocket 24 and a driven sprocket 25 on the left side of the rear wheel 17. The An engine intake system throttle body 27 is connected to the rear of the cylinder 23, and an air cleaner case 27 a is connected to the rear of the throttle body 27. Further, an exhaust pipe 28 of an engine exhaust system is connected to the front portion of the cylinder 23, and the exhaust pipe 28 is routed to the right side of the vehicle body and connected to a silencer 28a at the rear of the vehicle body.

A fuel tank 31 is disposed between the left and right main tubes 8. The upper half of the fuel tank 31 is positioned above the upper surface of the left and right main tubes 8. A fuel cap 31a for opening and closing the fuel filler opening is provided at the front upper end of the fuel tank 31, and a fuel cock 31b is provided at the front lower end. A cylinder 23 of the engine 21 is positioned below the fuel tank 31.
A seat frame 29A is connected to the rear part of the body frame 5, and a seat 29 for seating an occupant is supported on the seat frame 29A. The front portion of the seat 29 extends forward, and the front portion is supported on the upper surface of the rear portion of the fuel tank 31.

Here, referring also to FIG. 2, the fuel tank 31 is formed by integrally joining a tank body 32 made of titanium alloy and a fuel filler cylinder 41 also made of titanium alloy by seam welding.
The tank main body 32 forms a hollow monaca structure by integrally connecting upper and lower halves 33 and 34 that respectively form an upper portion and a lower portion thereof. The dividing surface S of the upper and lower halves 33 and 34 in the tank body 32 is inclined downward and downward along the upper surface of the main frame, and the joining flange 35 of the upper and lower halves 33 and 34 is provided along the dividing surface S so as to be lowered downward. It is done. Note that a fixing portion that is rubber-mounted on the vehicle body frame 5 is provided before and after the joining flange 35 (only the fixing portion on the front side of the tank is indicated by reference numeral 35a).

  The fuel tank 31 is used by exposing the material itself to the outer surface without being painted on the outer surface. When the vehicle is mounted, the upper half 33 above the joining flange 35 is more than the main frame. The upper half 33 is partly covered with a resin cover (not shown) and partly exposed to the exterior of the vehicle body. In addition, the structure by which the coating of the permeable coating (clear coating) was made on the outer surface of the tank, or the coating of the non-permeable coating was partially made.

A circular insertion port (fuel supply port) 36 that opens upward is formed at the upper end of the tank body 32 (upper half body 33), and the fuel supply port cylinder 41 is joined to the insertion port 36.
The fuel filler cylinder 41 has a cylindrical shape, and is integrally provided with a cap mounting portion 42 that protrudes upward from the tank body 32 and an extension portion 43 that faces the inside of the tank body 32.
For example, the cap mounting portion 42 is formed with a thread on the outer periphery thereof for screwing the oil supply cap 31a. On the other hand, the extension 43 has a cylindrical shape having a flat outer peripheral surface, and is inserted into the tank inside (inside the tank main body 32) from the insertion port 36.

  Here, below the insertion port 36 in the tank body 32 (upper half body 33), a cylindrical tank inner cylinder extending inward from the periphery of the insertion port 36 along the extension 43 of the oil supply port cylinder 41. The part 37 is provided integrally. The inner diameter of the insertion port 36 and the tank inner cylinder part 37 is substantially the same as the outer diameter of the extension part 43, and the tank inner cylinder is in a state where the outer peripheral surface of the extension part 43 is aligned with the inner peripheral surface of the tank inner cylinder part 37. Seam welding between the portion 37 and the extended portion 43 is performed.

The seam welding means that welding is performed by pressing and energizing a workpiece welded portion with a pair of seam rollers (roller electrodes), and rotating each seam roller relative to the workpiece welded portion. This is an existing method.
That is, as shown in FIG. 3, the tank inner cylinder portion 37 and the extension portion 43 that are aligned with each other are sandwiched between a pair of seam rollers R1 and R2, are pressurized and energized, and the seam rollers R1 and R2 are rotated and rotated. The tank inner cylinder part 37 and the extension part 43 are moved relative to each other so that the entire circumference of the tank inner cylinder part 37 and the extension part 43 is welded.

Here, in the welding machine that performs seam welding, the seam roller R2 that comes into contact with the inner peripheral surface from the inside of the extension 43 has a smaller diameter than the seam roller R1 that comes into contact with the outer peripheral surface from the outside of the tank inner cylinder portion 37. In addition, the configuration is such that it can be easily arranged inside the extension 43 which is a narrow space with respect to the outside of the tank inner cylinder portion 37.
This is because the size of the seam roller R1 outside the extension 43 is less likely to be limited because the seam roller R1 is located in the tank inner space, but the size of the seam roller R2 inside the inner cylinder portion 37 is likely to be limited by the size of the fuel filler opening. (That is, the seam roller R1 needs to be smaller than the size of the filler opening).
As shown in FIG. 4, depending on the shape of the fuel tank 31 (tank body 32), the space outside the extension 43 may be narrower than the inside of the inner cylinder portion 37. In such a case, the seam roller R1 , R2 may be reversed.

  The seam welding between the tank inner cylinder portion 37 and the extension portion 43 is performed in a state where the upper half body 33 is a single body before the upper and lower half bodies 33 and 34 are joined, and then the upper and lower half bodies 33 and 34 are joined. The fuel tank 31 is completed. That is, after completion of the fuel tank 31, the welded portion (tank inner cylinder portion 37 and extension portion 43) between the tank main body 32 and the fuel filler cylinder 41 is located inside the tank main body 32.

  As described above, the fuel tank 31 in the above-described embodiment is formed by integrally connecting the tank body 32 made of titanium alloy and the fuel filler cylinder 41 by seam welding. The tank body 32 is provided with an extension 43 that enters the inside, and the tank main body 32 has an insertion port 36 through which the extension 43 is inserted, and a tank inner cylinder 37 that extends inward from the periphery of the insertion port 36 along the extension 43. The extension portion 43 and the tank inner cylinder portion 37 are seam welded inside the tank.

  According to this configuration, even if a weld mark is generated at the welded portion between the tank body 32 and the fuel filler cylinder 41, the weld mark is not exposed to the outer surface of the tank because it is located inside the tank. Even when the material itself is exposed to the exterior of the vehicle, the exterior appearance of the vehicle can be kept good.

  In the method for manufacturing the fuel tank 31, a relatively small-diameter seam roller R <b> 2 is brought into contact with the inner peripheral surface of the extension portion 43, and a relatively large-diameter seam roller is disposed on the outer peripheral surface of the tank inner cylinder portion 37. By making R1 contact and seam-welding the extension 43 and the tank inner cylinder 37, it is easy to arrange a seam roller inside the extension 43 that is relatively narrow with respect to the tank inner cylinder 37 outside. Workability can be improved.

The present invention is not limited to the above-described embodiment. For example, the fuel tank 31 is not limited to a titanium alloy but may be made of a weldable metal such as an aluminum alloy, and the tank body 32 and the fuel filler cylinder. 41 may be joined by various methods such as arc welding or laser welding instead of seam welding. Further, when the fuel tank 31 is made of steel, it is desirable to perform sealing and brazing for preventing rust between the fuel filler cylinder 41 and the insertion port 36 on the outside of the tank.
And the structure in the said Example is an example of this invention, and it can apply to a three-wheel or four-wheel vehicle not only to a motorcycle, but various changes are possible in the range which does not deviate from the summary of the said invention. Needless to say.

1 is a left side view of a motorcycle according to an embodiment of the present invention. Fig. 3 is a left side view of the fuel tank of the motorcycle. It is sectional explanatory drawing around the fueling opening of the said fuel tank. FIG. 4 is a cross-sectional explanatory view corresponding to FIG. 3 showing a modification of the fuel tank.

Explanation of symbols

1 Motorcycle (vehicle)
31 Fuel Tank 32 Tank Body 36 Insertion Port 37 Tank Inner Tube Portion 41 Filler Port Tube Body 43 Extension Portion R1, R2 Seam Roller

Claims (3)

In a fuel tank formed by integrally joining a metal tank body and a fuel filler cylinder by welding,
An extension portion for entering the tank inside is provided in the fuel filler cylinder, and an insertion port through which the extension portion is inserted in the tank body, and a tank inner cylinder portion extending from the periphery of the insertion port to the inside of the tank along the extension portion A fuel tank, wherein the extension portion and the tank inner cylinder portion are welded inside the tank. 2. The fuel according to claim 1, wherein a seam roller is brought into contact with an inner peripheral surface of the extension portion and an outer peripheral surface of the tank inner cylinder portion, and the extension portion and the tank inner cylinder portion are seam welded. tank. In a fuel tank manufacturing method in which a metal tank body and a fuel filler cylinder are integrally coupled by welding,
An extension portion for entering the tank inside is provided in the fuel filler cylinder, and an insertion port through which the extension portion is inserted in the tank body, and a tank inner cylinder portion extending from the periphery of the insertion port to the inside of the tank along the extension portion A relatively small-diameter seam roller is brought into contact with the inner peripheral surface of the extension portion, and a relatively large-diameter seam roller is brought into contact with the outer peripheral surface of the tank inner cylinder portion so that the extension portion and the tank A method for manufacturing a fuel tank, comprising seam welding a cylindrical portion.

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