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EP-4737281-A1 - FUEL TANK AND METHOD FOR MANUFACTURING LOWER PANEL

EP4737281A1EP 4737281 A1EP4737281 A1EP 4737281A1EP-4737281-A1

Abstract

A fuel tank (40) being supported from below by a pair of tank rails (12) of a saddle-type vehicle (1), the fuel tank includes: a lower panel (42) configured to bulge downward so as to be inserted between the pair of tank rails; and an upper panel (41) configured to bulge upward at a position above the pair of tank rails. A flange (44) on an outer edge of the lower panel and a flange (43) on an outer edge of the upper panel are joined together. A step portion (45) is formed on inside of the flange of the lower panel, the step portion being one step lower than the flange, and a dome portion (46) is formed on inside of the step portion so as to deeply protrude downward from the step portion. The step portion is supported by the pair of tank rails, and the dome portion is inserted between the pair of tank rails.

Inventors

  • TOKUNAGA, KATSUHIKO
  • TANAKA, HIROSHI
  • SATO, TOSHIHIKO

Assignees

  • Suzuki Motor Corporation

Dates

Publication Date
20260506
Application Date
20250822

Claims (4)

  1. A fuel tank (40) being supported from below by a pair of tank rails (12) of a saddle-type vehicle (1), the fuel tank comprising: a lower panel (42) configured to bulge downward so as to be inserted between the pair of tank rails; and an upper panel (41) configured to bulge upward at a position above the pair of tank rails, wherein a flange (44) on an outer edge of the lower panel and a flange (43) on an outer edge of the upper panel are joined together, a step portion (45) is formed on inside of the flange of the lower panel, the step portion being one step lower than the flange, and a dome portion (46) is formed on inside of the step portion so as to deeply protrude downward from the step portion, and the step portion is supported by the pair of tank rails, and the dome portion is inserted between the pair of tank rails.
  2. The fuel tank according to claim 1, wherein a support surface having a flat shape is formed on the step portion along upper surfaces of the pair of tank rails, and the support surface of the step portion is supported from below by the pair of tank rails.
  3. The fuel tank according to claim 1 or 2, wherein the flange on the outer edge of the lower panel and the flange on the outer edge of the upper panel are curved in a downwardly bulging arc shape in a side view.
  4. A method for manufacturing a lower panel (42) of a fuel tank (40) in which a flange (43) on an outer edge of an upper panel and a flange (44) on an outer edge of a lower panel are joined, the lower panel bulging downward so as to be inserted between a pair of tank rails (12) of a saddle-type vehicle (1) in a state in which the fuel tank is supported by the pair of tank rails, the method comprising: pressing a predetermined portion of a blank material that becomes a step portion (45) after manufacturing of the lower panel, and forming a dome portion (46) that is inserted between the pair of tank rails by a first deep drawing; and pressing a predetermined portion of the blank material that becomes a flange after manufacturing of the lower panel, and forming the step portion that is supported by the pair of tank rails by a second deep drawing, wherein the step portion is formed on inside of the flange of the lower panel, the step portion being one step lower than the flange, and the dome portion is formed on inside of the step portion so as to deeply protrude downward from the step portion.

Description

TECHNICAL FIELD The present invention relates to a fuel tank and a method for manufacturing a lower panel. BACKGROUND ART A saddle-type vehicle is known in which a fuel tank is covered with a cover member (see, for example, Patent Literature 1). The fuel tank described in Patent Literature 1 has an upper and lower split structure made up of an upper panel and a lower panel, and a flange of the upper panel and a flange of the lower panel are seam-welded. The cover member is attached to a vehicle body so as to hide a flange-shaped joint between the upper panel and the lower panel. The cover member is formed by combining right and left metal side covers and a resin center cover, and the metal side covers increase rigidity against knee grip. CITATION LIST PATENT LITERATURE Patent Literature 1: JP2022-184501A Incidentally, the fuel tank as described above is supported by a pair of tank rails, and in order to ensure a capacity, it is necessary to insert the lower panel between the pair of tank rails. However, due to restriction in a width direction imposed by the pair of tank rails, it is difficult to form a deep-bottomed lower panel with high accuracy using deep drawing, which has a narrow opening. SUMMARY The present invention is made in consideration of the above-described point, and has an object to provide a fuel tank and a method for manufacturing a lower panel that can accurately form a deep lower panel to ensure a capacity. A fuel tank according to an aspect of the present invention is a fuel tank being supported from below by a pair of tank rails of a saddle-type vehicle, the fuel tank includes: a lower panel configured to bulge downward so as to be inserted between the pair of tank rails; and an upper panel configured to bulge upward at a position above the pair of tank rails, where a flange on an outer edge of the lower panel and a flange on an outer edge of the upper panel are joined together, a step portion is formed on inside of the flange of the lower panel, the step portion being one step lower than the flange, and a dome portion is formed on inside of the step portion so as to deeply protrude downward from the step portion, and the step portion is supported by the pair of tank rails, and the dome portion is inserted between the pair of tank rails, thereby solving the above-mentioned problem. According to the fuel tank of the aspect of the present invention, the fuel tank is stably supported on the pair of tank rails by the step portion of the lower panel, and an inner space between the pair of tank rails is effectively utilized by the dome portion of the lower panel. A sufficient capacity of the fuel tank is ensured by the step portion on an upper side of the pair of tank rails and the dome portion inserted between the pair of tank rails. Furthermore, by forming the dome portion and the step portion separately, the dome portion having a deep bottom is formed within a range that is not restricted in a width direction by the pair of tank rails. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a left side view of a saddle-type vehicle according to an example.FIG. 2 is a left side view of a periphery of a fuel tank according to the example.FIG. 3 is a bottom view of the periphery of the fuel tank according to the example.FIG. 4 is a side view of a blank material after a first deep drawing in the example.FIG. 5 is a bottom view of the blank material after the first deep drawing of the example.FIG. 6 is a side view of a blank material after a second deep drawing of the example.FIG. 7 is a bottom view of the blank material after the second deep drawing of the example. DESCRIPTION OF EMBODIMENTS A fuel tank according to an aspect of the present invention is supported from below by a pair of tank rails of a saddle-type vehicle. The fuel tank is formed by joining a flange on an outer edge of a lower panel and a flange on an outer edge of an upper panel. The lower panel bulges downward so as to be inserted between the pair of tank rails, and the upper panel bulges upward at a position above the pair of tank rails. A step portion is formed on the inside of the flange of the lower panel, the step portion being one step lower than the flange, and a dome portion is formed on the inside of the step portion so as to deeply protrude downward from the step portion. The step portion allows the fuel tank to be stably supported on the pair of tank rails, and the dome portion is inserted between the pair of tank rails, making effective use of an inner space between the pair of tank rails. A sufficient capacity of the fuel tank is ensured by the step portion on an upper side of the pair of tank rails and the dome portion inserted between the pair of tank rails. Furthermore, by forming the dome portion and the step portion separately, the dome portion having a deep bottom is formed within a range that is not restricted in a width direction by the pair of tank rails. Example Hereinafter, a saddle-type vehicle according to this exa