Title of Invention

FUEL SUPPLY SYSTEM

Abstract

A fuel pump 24 is installed into a fuel tank 18 through an opening 22 formed in an upper surface of a ceiling wall 18b of the fuel tank 18. The fuel pump 24 includes a motor 25 having a suction port and a pump case 27 having on an upper surface thereof a connector 34 for the discharge of fuel. A flange 28 having plural pawl portions 29 is integrally formed on an outer periphery of the pump cse 27. The flange 28 covers the opening 22 and the pawl portions 29 are arranged so as to engage with the pawl portions 31 formed on the fuel tank 18 side.

Full Text

[Technical Field] The present invention relates to a fuel supply system having a fuel pump installed into a fuel tank. Particularly, the present invention is concerned with a fuel supply system which permits easy installation of a fuel pump into a fuel tank. [Background Art] In conventional fuel supply systems, there sometimes is adopted a construction wherein plural stud bolts erected outwards around an opening formed in a ceiling wall of a fuel tank, holes of a retainer (retaining member) for a fuel pump are engaged with the stud bolts and nuts are tightened onto the bolts. There also is known a fuel supply system wherein a fuel pump is installed within a fuel tank mounted on a vehicle (see, for example, Japanese Patent Laid-open No. 2003-120454) . In this known fuel supply system, an annular member having plural locking pawls projecting radially inwards from a peripheral edge of an opening formed in a ceiling wall of the fuel tank is welded to the ceiling wall. On the other hand, the fuel pump is provided with a mounting flange for closing the opening. Further provided is a lock ring having a portion for abutment against an upper surface of the flange to hold down the flange and plural engaging portions for engagement with the locking pawls. When the lock ring is rotated by a predetermined angle, the plural locking pawls come into engagement respectively with the plural engaging portions of the lock ring, whereby the mounting flange is put in close contact with an upper surface of the ceiling wall through the seal member of the flange lower surface. In this way, the mounting flange is fixed to a predetermined position of the fuel tank to close the opening. Thus, according to conventional constructions, bolt and nut are combined with a retaining member or a lock ring is used to fix the fuel pump. [Patent Document 1] Japanese Patent Laid-open No. 2003-120454 [Disclosure of the Invention] [Problem to be Solved by the Invention] In the conventional fuel supply systems, plural parts are needed for assembling the fuel pump and the fuel tank. Also in the system disclosed in the above publication, the lock ring used therein is a separate part from the fuel pump and therefore a further simplification of the assembling work is desired. It is an object of the present invention to provide a fuel supply system which permits a fuel pump to be installed into a fuel tank without using any part separated from the fuel pump. [Means for Solving the Problem] The present invention which has been accomplished for achieving the above-mentioned object is firstly characterized in that a fuel pump which is installed into a fuel tank through a circular opening formed in a ceiling wall of the fuel tank comprises a pump body disposed within the fuel tank and a pump case connected to the pump body and provided at an upper position thereof with a fuel discharge portion for the discharge of fuel to the exterior of the fuel tank. The pump case is integrally provided with a flange, the flange having a plurality of first pawl portions projecting radially from a circular outer periphery. A plurality of second pawl portions which define gaps for insertion therein of the first pawl portions between the second pawl portions and an upper surface of the ceiling wall are formed on an edge of the opening of the fuel tank toward the center of the opening. An arrangement spacing of the first pawl portions and that of the second pawl portions are set so that the first pawl portions can each be fitted in between adjacent second pawl portions from above. The present invention is secondly characterized in that the fuel supply system further comprises a stopper for defining a rotation end of the flange at the time of fitting each of the first pawl portions in between adjacent second pawl portions from above and then rotating the pump case within a plane of the flange to let the first pawl portions be inserted in between the second pawl portions and the upper surface of the ceiling wall, the stopper being a rising portion formed in any of the first pawl portions or of the second pawl portions. The present invention is thirdly characterized in that the first pawl portions have respective stepped portions adapted to engage end portions of the second pawl portions at the rotation-stopped position by the stopper to prevent the first pawl portions from return in the direction opposite to the rotational direction of the flange. The present invention is fourthly characterized in that an upper surface of the pump case has a recess or projection portion for engagement therewith of a jig or a tool at the time of rotating the pump flange. [Effect of the Invention. According to the present invention having the above first to fourth features, the fuel pump can be connected to the fuel tank without using any independent part separate from the fuel pump, whereby the management of parts and the simplicity of works are improved. More particularly, at the time of installing the fuel pump into the fuel tank, the first pawl portions of the flange formed integrally with the pump case, the first pawl portions being each formed so as to be positioned between adjacent second pawl portions, are fitted in the second pawl portions from above, and the flange is rotated within a plane thereof, whereby the first pawl portions are held grippingly in the gaps between the second pawl portions and the upper surface of the ceiling wall of the fuel tank, and the pump case is combined with the fuel tank. [0011] Particularly, according to the second feature, since a rotation end of the flange is determined by the stopper when formed in any of the first pawl portions, the positioning work at the time of installing the fuel pump into the fuel tank becomes constant. As a result, the direction of a suction port formed in the pump body within the fuel tank also becomes constant, so that fuel can be sucked up to a predetermined amount of residual fuel. [0012] According to the third feature, at a predetermined position, the flange can be prevented from return in the direction opposite to its rotational direction. Further, according to the fourth feature, a jig or a tool can bo easily brought into a proper position at the time of installing or removing the fuel pump into or from the fuel tank. [Best Mode for Carrying Out the Invention] [0013] An embodiment of the present invention will now be described with reference to the drawings. [Brief Description of the Drawings] [0029] [Fig. 1] Fig. 1 is a sectional view of a fuel tank with a fuel pump attached thereto according to an embodiment of the present invention; [Fig. 2] Fig. 2 is a plan view of a fuel tank with a fuel pump attached thereto according to an embodiment of the present invention; [Fig. 3] Fig. 3 is a plan view of the fuel pump in a preparatory state for mounting the fuel pump according to an embodiment of the present invention; [Fig. 4] Fig. 4 is a perspective view of a principal portion of the fuel tank .with the fuel pump attached thereto according to an embodiment of the present invention; [Fig. 5] Fig. 5 is a sectional view taken on line A-A in Fig. 2; [Fig. 6] Fig. 6 is a sectional view taken on line B-B in Fig. 2; and [Fig. 7] Fig. 7 is a left side view of a scooter type motorcycle provided with the fuel tank according to an embodiment of the present invention.Fig, 7 is a perspective side view of a scooter type motorcycle as a small-sized vehicle on which a fuel supply system according to an embodiment of the present invention is mounted. A body frame 2 of the motorcycle indicated at a numeral 1 comprises a head pipe 2a, a down-tube portion 2b extending downward at an acute angle from a rear surface of the head pipe 2a, a floor support portion 2c extending horizontally backward from a lower end of the down-tube portion 2b, a pillar portion 2d rising vertically from a rear end of the floor support portion 2c, and a rear rail portion 2e inclined and extending backwardly upwards from an upper end of the pillar portion 2d. A steering shaft 5a extending upward from a front fork 4 which supports a front wheel 3f through an axle is supported steerably by the head pipe 2a. A handle bar 5b is connected to an upper portion of the steering shaft 5a. A power unit 6 is suspended from the upper ends of the pillar portion 2d vertically swingably through a pivot shaft 7. A rear cushion 8 is mounted between the power unit 6 and the rear rail portion 2e. The power unit 6 comprises an engine 9 having a cylinder portion 9a which is inclined forward in a nearly horizontal state and a continuously variable transmission 10 integrally provided with a transmission case 10a which extends backward along one side portion of the engine 9. A rear wheel 3r as a drive wheel is supported through an axle by a rear end portion of the transmission case 10a. A luggage box 15 for receiving large-sized goods therein such as a helmet is mounted on the rear rail portion 2e and a rider seat 16 serving also as a lid of the luggage box 15 is connected to an upper front end portion of the box 15 through a hinge 16a so that it can be opened and closed. An opening (not shown) is formed centrally of the floor support portion 2c and a fuel tank 18 is inserted and fixed into the opening. The structure of the fuel supply system including the fuel tank 18 will now be described. Fig. 1 is a cross sectional view of the fuel tank, Fig. 2 is plan view thereof, and Fig. 3 is a perspective view of a principal portion thereof. The fuel tank 18 has a substantially horizontal ceiling wall 18b, and a fuel supply port 20 is open to the ceiling wall 18b, with a tank cap (not shown) being applied to the fuel supply port 20. Further, an opening 22 larger than the oil supply port 20 is formed in the ceiling wall 18b and a fuel pump 23 is installed vertically through the opening 22. The fuel pump 23 is disposed in a front portion, ahead of the fuel supply port 20, of the fuel tank 18. A principal portion of the fuel pump 23 is accommodated within the fuel tank 18 so that the fuel present within the fuel tank can be pumped up. The fuel pump 2 3 includes an electric fuel pump body (motor) 24 immersed into fuel oil, a fuel strainer 26 connected to a suction port 25 of the motor 24, and a pump case 27 which houses therein and holds a pressure regulator for regulating the discharge pressure of the fuel pump 23 and a check valve (neither shown). The pump case 2 7 has a flange 2 8 which is formed in a circular shape in top view and which extends radially horizontally and covers the opening 22. A plurality of radially expanded pawl portions (first pawl portions) 29 are formed at predetermined intervals on the outer periphery of the flange 28. The arrangement spacing of the pawl portions 29 is set so as to be in conformity with that of plural pawl portions 31 of a ring plate 30 which is bonded to the fuel tank 18 along the opening 22. The pawl portions 29 and 31 are engaged with each other and the pump case 2 7 is connected to the ceiling wall 18b of the fuel tank 18. As to the structure for mounting and removal of the fuel pump 23 to and from the fuel tank 18, it will be described later. An annular recess 33 for receiving a sealing member, i.e., packing 32, therein is formed in a lower surface of the flange 28 of the pump case 27, and an upper surface of the ceiling wall 18b and the lower surface of the flange 28 are in close contact with each other through the packing 32. A connector 34 for the discharge of fuel and a connector 3 for supplying the motor 24 with electric power provided on top of the pump case 2 7 in an exposed state to the exterior of the fuel tank 18 so that a pipe connected to a fuel injection valve and a power supply line (neither shown) can be connected to the connectors 34 and 35, respectively. Next, the engaged portion between each of the pawl portions of the flange and the associated pawl portion of the ring plate will be described in detail. Fig. 4 is a plan view of the fuel tank, showing a disengaged state of the pawl portions 2 9 and 31, i.e., a state in which the flange 28 is merely put on the ceiling wall 18b of the fuel tank 18. Figs. 5 and 6 are sectional views taken on line A-A and line B-B, respectively, in Fig. 2. For installing the fuel pump 23 into the fuel tank 18, first, as shown in Fig. 4, the fuel pump 23 is positioned with respect to the fuel tank 18 so that the pawl portions 29 of the flange 28 are positioned in the recess portions of the ring plate 30, i.e., between the pawl portions 31. Some of the pawl portions 2 9 and 31, indicated at 29a and 31a, are different in shape from the other pawl portions. This is for determining the direction of the fuel pump 23 so that the fuel strainer 2 6 assumes a predetermined position on the bottom of the fuel tank 18. As shown in Fig. 1, the pawl portions 2 9 of the flange 28 are fixed below the pawl portions 31 of the ring plate 3 0 and in a sandwiched state in between the ceiling wall 18b and the pawl portions 31. Therefore, the pump case 27 is rotated clockwise from its state shown in Fig. 4, causing the pawl portions 2 9 to get in under the pawl portions 31. As shown in Fig. 6, each pawl portion 31 has a face 31b parallel to the ceiling wall 18b and a slant face 31c having an angle relative to the ceiling wall 18b. The pawl portions 29 of the flange 28 are sandwiched in between the parallel faces 31a and the ceiling wall 18b, whereby the flange 28 is fixed to the ceiling wall 18b. As shown in Fig. 6, the pawl portions 29 are respectively provided with portions as stoppers 29b which portions are upright relative to the ceiling wall 18b. Therefore, the rotation of the flange 28 is stopped at the position where the stoppers 2 9b are abutted against end faces of the pawl portions 31. On the other hand, at the position where the stoppers 29b are abutted against the end faces of the pawl portions 31, the pawl portions 31 of the ring plate 3 0 get over stepped portions 2 9c as return preventing portions formed in the pawl portions 29 of the flange 28, as can be seen from the sectional shape of Fig. 5. In this state in which the pawl portions 31 have once got over the stepped portions 29c, the pawl portions 29 and 31 are not disengaged from each other unless the pump case 27 is rotated counterclockwise in Fig. 1 with a force larger than the assembling force. The stoppers 2 9b may be formed in all of the pawl portions 29, but such a stopper as described above may be formed in only one pawl portion 29, or preferably plural such stoppers as described above are formed in alternate pawl portions 29. For rotating the pump case 27, it is preferable that a lug, rib, or recess, be formed on an upper surface of the pump case 27. The reason is that this is convenient for a rod-like jig or tool for rotating the pump case 27 to be engaged with the lug or rib, or for engagement of a jig or tool having a lug into the recess. E0028] The stoppers for stopping the return of the pump case 27 are not limited to those formed in the pawl portions 29 on the flange 28 side, but downwardly extending vertical portions may be formed in the pawl portions 31 on the ring plate 3 0 side so that the front ends in the rotational direction of the pawl portions 29 come into abutment against the vertical portions. [Explanation of Reference Characters] 1 ... motorcycle, 18 ... fuel tank, 18b . . . tank ceiling wall, 22 ... opening, 23 ... fuel pump, 24 ... fuel pump body, 27 ... pump case, 28 flange, 29 ... (first) pawl portion, 29a . . . stopper, 3 0 ... ring plate, 31 ... (second) pawl portion. WE CLAIMS :- 1. A fuel supply system comprising a fuel tank (18) and a fuel pump (23) which is installed into said fuel tank (18) through a circular opening formed in a ceiling wall of said fuel tank (18), wherein said fuel pump (23) comprises: a pump body (24) disposed within said fuel tank; and a pump case (27) connected to said pump body and provided at an upper position thereof with a fuel discharge portion for the discharge of fuel to the exterior of said fuel tank; characterized in that said pump case (27) Is Integrally provided with a flange (28), said flange having a plurality of first pawl portions (29) projecting radially from a circular outer periphery; a plurality of second pawl portions (31) which define gaps for insertion therein of said first pawl portions (29) between the second pawl portions (31) and an upper surface of said ceiling wall being formed on an edge of said opening of said fuel tank (18) toward the center of the opening; and an arrangement spacing of said first pawl portions (29) and that of said second pawl portions (31) are set so that the first pawl portions can each be fitted in between adjacent said second pawl portions (31) from above. 2. A fuel supply system as claimed in claim 1, further comprising a stopper (29a) for defining a rotation end of said flange at the time of fitting each of said first pawl portions (29) in between adjacent said second pawl portions (31) from above and then rotating said pump case (27) within a plane of said flange (28) to let said first pawl portions (29) be inserted in between said second pawl portions (31) and said upper surface of said ceiling wall; wherein said stopper (29a) is a rising portion formed in any of said first pawl portions (29) or of said second pawl portions (31). 3. A fuel supply system as claimed in claim 2, wherein said first pawl portions (29) have respective stepped portions adapted to engage end portions of said second pawl portions (31) at the rotation-stopped position by said stopper to prevent the first pawl portions (29) from return in the direction opposite to the rotational direction of said flange (28). 4. A fuel supply system as claimed in any of claims 1 to 3, wherein an upper surface of said pump case (27) has a recess or projection, portion for engagement therewith of a jig or a tool at the time of rotating said pump flange (28).

Documents:

34-del-2005-abstract.pdf

34-del-2005-claims.pdf

34-del-2005-complete specification (granted).pdf

34-del-2005-correspondence-others.pdf

34-del-2005-correspondence-po.pdf

34-del-2005-description (complete).pdf

34-del-2005-drawings.pdf

34-del-2005-form-1.pdf

34-del-2005-form-18.pdf

34-del-2005-form-2.pdf

34-del-2005-form-3.pdf

34-del-2005-form-5.pdf

34-del-2005-gpa.pdf

34-del-2005-petition-137.pdf

34-del-2005-petition-138.pdf