JP2007125571A - Method for joining members, structure of joined members, and fuel tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for joining members, which method can easily form a projection suitable for the projection welding, and further to provide a structure of joined members, and to provide a fuel tank. <P>SOLUTION: A base 7 to be joined to a steel sheet 2a having the aperture portion of a fuel tank is manufactured by working the steel sheet by a press so as to produce an annular member. In this press work, a curved portion 36 is provided near the peripheral portion 7a of a base material 33 together with bent portions 34, 35 for forming a stepped portion 50 necessary for engaging with a fuel pump unit. As a result, the projection 36a formed by the curved portion 36 has a sharp ridge having the cross sectional angle of nearly 90° without carrying out cutting work, etc. The projection 36a can serve as the projection for the projection welding, in which the steel sheet 2a and the base 7 are arranged at a preset position between an upper electrode 45 and a lower electrode 46 and are pressed while supplying electric current. The shape of the projection is suitable for the large diameter ring projection welding, etc. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a member joining method, a member joining structure, and a fuel tank, and more particularly to a member joining method, a member joining structure, and a fuel tank capable of easily forming a projection suitable for projection welding.

  Conventionally, as a type of resistance welding used for joints that require a sealing property, a projection is provided on the material to be welded, and energized and pressurized by welding electrodes arranged above and below the projection, Projection welding is known in which heat and pressure are concentrated to cause melting or plastic flow to join. Resistance welding is a state in which metal materials to be joined are overlapped or butted together, and a current of several thousand to several tens of thousands of amperes is passed through the materials to be welded. It is a general term for the method of joining under pressure. In particular, projection welding performed in an annular shape is called ring projection welding.

In Patent Document 1, when ring projection welding is performed, when the thickness of a member to be welded provided with the projection is t (mm), the width of the top of the projection is t (mm) or more and 2t ( mm) The joining method formed below is disclosed. According to the joining method, compared to the case where the width of the top of the projection is narrower than t (mm), it is possible to suppress excessive heat generation due to resistance heat generation and prevent the projection from being melted and scattered. Even when applied to stainless steel having a larger electric resistance than that of a normal steel plate, good ring projection welding can be performed.
Japanese Patent Laid-Open No. 2002-239738

  As a method of forming a projection on a material to be welded, conventionally, a method of pressing a mold having a convex portion from the back side of the material to be welded is known, but in this method, the contact area of the projection tip with the counterpart member Tends to grow. For this reason, in the large-diameter ring projection welding, there is a problem that current is dispersed and it becomes difficult to perform good joining. In addition, as in the projection described in the above-mentioned Patent Document 1, in order to accurately form the shape into a predetermined dimension, it is necessary to perform cutting or the like, so that there is a problem that the manufacturing process increases. .

  An object of the present invention is to provide a member joining method, a member joining structure, and a fuel tank that can solve the above-described problems of the prior art and can easily form protrusions suitable for projection welding.

  In order to achieve the above-described object, the present invention provides a method for joining two members having a plate-like portion by projection welding, wherein the end of the plate-like portion of one member is curved toward the welding surface side. Forming a protrusion, superimposing the end portion on the plate-like portion of the other member, sandwiching the two members with welding electrodes, and energizing the two members with the electrodes. The first feature is that it includes a step of performing projection welding by applying pressure.

  Further, in a member joint structure for joining two members having a plate-like portion by projection welding, a protrusion formed by curving an end of the plate-like portion of one member on the welding surface side, and the protrusion A second feature is that it includes a projection welded portion that is in contact with the plate-like portion of the member on the other side and is formed by energization and pressurization.

  Furthermore, the fuel tank is configured to receive the fuel pump unit from the opening of the fuel tank, and includes a substantially annular base member having a protrusion formed by curving the end of the peripheral edge toward the welding surface by pressing. The third feature is that the end is a projection, the base member is joined to the wall of the fuel tank by ring projection welding, and the end of the fuel pump unit is fitted and fixed to the base member. There is.

  According to the first aspect of the present invention, since the projection to be a projection can be formed by a step of bending the member, a member joining method capable of easily forming a predetermined projection without increasing the manufacturing process is obtained. . In addition, it is possible to obtain a projection having a sharp shape suitable for large-diameter ring projection welding or the like without performing cutting or the like.

  According to the second aspect of the present invention, since the projection to be a projection can be formed by a process of bending the member, a member bonded structure capable of easily forming a predetermined projection without increasing the manufacturing process is obtained. It is done. In addition, it is possible to obtain a projection having a sharp shape suitable for large-diameter ring projection welding or the like without performing cutting or the like.

  According to the invention of claim 3, since the projections necessary for ring projection welding can be obtained by pressing without performing cutting or the like, the manufacturing process of the fuel tank can be reduced. Further, since a projection having a sharp shape suitable for ring projection welding of the base member can be obtained, the base member and the fuel tank wall surface can be favorably joined.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of an embodiment of a motorcycle 100 to which the present invention is applied. A pair of left and right front forks 85 are pivotally attached to a head pipe 81 fixedly connected to the main frame 80, and a front wheel WF is pivotally supported at the lower end thereof. The front fork 85 can be steered by a handle 82, and the front fender 84 covering the front wheel WF is steered integrally with the front fork 85. A front cover 83 is disposed above the front fender 84 and covers the main frame 80 together with the upper cover 86. An engine 87 as an internal combustion engine is fixedly suspended below the main frame 80. A seat frame 90 that supports a body cover 88 and a seat 89 on which an occupant is seated is connected to the rear of the main frame 80, and the fuel tank 1 is installed below the seat 89 behind the vehicle. Yes. The swing arm 91 having one end shaft attached to the lower rear portion of the main frame 80 is suspended by a rear cushion 92 connected to the seat frame 90 so that the swing arm 91 can swing about the one end shaft. In addition, a rear wheel WR as a drive wheel is rotatably supported at the other end. The member joining method according to the present invention is applied to the fuel tank 1.

  FIG. 2 is a schematic explanatory view of the fuel tank 1 to which the member joining method according to one embodiment of the present invention is applied. The fuel tank 1 is formed as an integral container by welding an upper member 2 and a lower member 3 press-formed from a steel plate at each peripheral edge portion 4. An upper surface portion of the upper member 2 is provided with a fuel filler port 5 and an opening 6 for attaching the fuel pump unit 10. A lid that is detachable or openable when the fuel tank 1 is mounted on the vehicle is provided on the upper portion of the fuel filler opening 5 that is opened and closed each time fueling is performed. On the other hand, once the fuel pump unit 10 is attached when the fuel tank 1 is assembled, the opening 6 is not opened except when the fuel pump unit 10 is disassembled and maintained.

  The fuel pump unit 10 has a built-in drive motor that pumps the fuel in the fuel tank 1 under a lid 13 provided with a connector 15 for receiving a fuel discharge nozzle 14 and a drive signal for the drive motor. A cylindrical main body 11 and a strainer 12 incorporating a filter for filtering impurities mixed in the fuel are connected to each other.

  A base 7 as a base member for attaching the fuel pump unit 10 and a plate 8 as a guide member are joined to the opening 6. The base 7 is provided with projections (projections) on the material to be welded, and is energized and pressurized by welding electrodes arranged above and below it, thereby concentrating heat and pressure on the projections to cause melting or plastic flow. The upper member 2 is joined by projection welding. The plate 8 is joined to the upper surface of the base 7 by spot welding at four locations.

  Between the inner wall surface of the base 7 and the lid portion 13, an O-ring 16, which is a sealing seal having a substantially circular cross section formed of an elastic resin or the like, is disposed. The fuel pump unit 10 is hermetically fixed to the fuel tank 1 by inserting a retainer 20 as a retainer after the whole is inserted through the opening 6.

  FIG. 3 is a side view of the fuel tank 1. The same reference numerals as those described above denote the same or equivalent parts as described above. The steel plate 2 a forming the upper member 2 is bent at a substantially right angle toward the lower member 3 at the peripheral edge of the opening 6. The projection welding between the steel plate 2a and the base 7 is performed as ring projection welding over the entire periphery of the peripheral edge portion 7a of the base 7, and the member joining method according to an embodiment of the present invention is the ring projection welding. Applied to welds. The plate 8 is formed with a step for providing a gap in which the retainer 20 can be inserted between the plate 8 and the base 7.

  FIG. 4 is a schematic explanatory view of a mounting portion of the fuel pump unit according to one embodiment of the present invention. The same reference numerals as those described above denote the same or equivalent parts as described above. With reference to the figure seen from the direction in which the retainer 20 is inserted, the installation procedure of the fuel pump unit 10 will be described. First, the O-ring 16 is disposed so as to be accommodated in a stepped portion 50 formed on the inner peripheral portion of the base 7. Next, the fuel pump unit 10 is inserted into the opening 6 from the tip of the strainer 12 while tilting. And when the main-body part 11 is settled in the opening part 6, between the outer peripheral part of the said cover part 13 and the step part of the base 7, the said O ring 16 is comprised so that a sealing effect may be exhibited. In this state, when the retainer 20 is inserted into the gap 18 between the base 7 and the plate 8, the tip of the retainer 20 passes through the upper surface side of the lid portion 13 and the gap 18 on the side opposite to the insertion direction. Will enter. With the configuration as described above, the fuel pump unit 10 holds the state fixed to the fuel tank 1 unless the retainer 20 is removed. In this embodiment, spot welding for joining the plate 8 to the base 7 is performed at the four spot welds 17, but is not limited thereto.

  FIG. 5 is a cross-sectional view of the fuel pump unit 10. The same reference numerals as those described above denote the same or equivalent parts as described above. The fuel pump unit 10 incorporates a drive motor 30 inside a main body 11 which is a cylindrical housing, and an impeller 32 as an impeller is attached to a rotary shaft 31 thereof. When the connector 15 receives a drive signal from an ECU (not shown) and the drive motor 30 rotates, the impeller 32 rotates to suck out fuel from the strainer 12. The fuel sucked out by the rotational force of the impeller 32 is pumped up above the fuel pump unit 10 while lubricating the drive motor 30 and is supplied to a fuel injection device that supplies fuel to the engine 87 from the discharge port 14. It will be discharged toward. In this embodiment, since the O-ring 16 having a substantially circular cross section is used as the sealing member for hermetically fixing the plate 7, the stepped portion 40 that comes into contact with the O-ring 16 is provided with an annular surface seal by a planar member. Compared to the conventional method used, the size can be greatly reduced. In accordance with this, the configuration of the fuel pump unit 10 is also made “upward specification” in which the discharge nozzle 14 and the connector 15 are provided on the upper surface of the lid portion 13, thereby reducing the diameter of the lid portion 13 as much as possible. ing.

  6 (a) and 6 (b) are a top view and a side view of the lid part 13, respectively. The same reference numerals as those described above denote the same or equivalent parts as described above. In the present embodiment, once the inserted retainer 20 is fixed at a predetermined position, the retainer 20 is configured not to be removed (locked) unless a predetermined operation is intentionally performed. The lock function is exhibited mainly by the shapes of the lid portion 13 and the retainer 20. In the lid portion 13 shown in the figure, slopes 13a and 13b as convex portions are provided at three locations that come into contact with an arbitrary portion of the substantially U-shaped retainer 20 when the retainer 20 is inserted. The slopes 13a and 13b are shaped so that the slope rises gently from the direction in which the retainer 20 is inserted.

  7A and 7B are a top view and a side view of the retainer 20, respectively. The same reference numerals as those described above denote the same or equivalent parts as described above. The retainer 20 is formed of a thin steel plate or the like that elastically deforms when stress is applied from the outside and returns to its original shape when released from the stress. A retainer 20 having a flat plate shape excluding the bent portion 25 as a handle includes a main plate 21 as an engaging member, and a sub plate 23 as a pressing member connected to the inside of the main plate 21 by a connecting portion 22. 24. Further, the leading end portion 23 a as a locking portion of the sub plate 23 has a protruding length shorter than the leading end portion 21 a of the main plate 21. In addition, a protrusion 24c is provided on the retainer insertion direction side at the center of the substantially U-shaped sub-plate 24, and a substantially linear locking portion on the outer peripheral side of each of the two bent portions 24a. 24b is formed.

  FIG. 8 is a top view of the fuel pump unit 10 attached to the fuel tank 1. The same reference numerals as those described above denote the same or equivalent parts as described above. Hereinafter, the lock function of the retainer 20 will be described in detail with reference to FIG. 9 which is a sectional view taken along line AA of FIG. 8 and FIG.

  First, when the fuel pump unit 10 is inserted into the opening 6 (see FIG. 4) and pushed into the stepped portion 50 of the base 7 until the bottom surface of the lid portion 13 comes into contact, the O-ring 16 is deformed to form a predetermined seal. It becomes effective. Here, when the retainer 20 is inserted into the gap 18 (see FIG. 4) formed between the base 7 and the plate 8 from the left in the figure, the front end 21a of the main plate 21 of the retainer 20 is The plate 13 that is a guide member is engaged through the upper surface of the portion 13 and reaches the gap 18 on the right side of the drawing. At this time, the front end portion 23a of the sub-plate 23 is raised along the slope 13b and elastically deforms the sub-plate 23. As a result, the sub-plate 23 presses the lid portion 13, and the tip end portion 23 a is in contact with or substantially in contact with the side surface portion of the inner periphery of the plate 8.

  On the other hand, the protrusion 24c of the subplate 24 is raised along the slope 13a of the lid 13 to elastically denature the subplate 24. As a result, the sub-plate 24 presses the lid portion 13 and the locking portion 24 b comes into contact with or substantially contacts the side surface portion of the inner periphery of the plate 8. From the above-described operation, the retainer 20 exhibits a lock function that cannot move in either the inserting direction or the pulling direction by the sub-plates 23 and 24 raised by the slopes 13a and 13b. When removing the fuel pump unit 10 from the fuel tank 1, the sub-plate 24 is elastically deformed by performing a predetermined operation of pressing the vicinity of the engaging portion 24a of the sub-plate 24 downward. Then, it is only necessary to pull out from the direction in which the retainer 20 is inserted while releasing the locking state of the locking portion 24a.

  According to the fuel pump mounting structure as described above, the O-ring having a substantially circular cross section is used for the seal member and the mounting bolt is not required, so the diameter of the parts related to the mounting of the fuel pump unit can be reduced. Thus, the space required for mounting can be greatly reduced. In addition, the mounting bolt is not required and the fuel pump unit can be hermetically fixed simply by inserting the retainer, so that the work process during assembly can be reduced. Further, the configuration of the lid and the retainer is configured to have a lock function that the retainer cannot be removed unless a predetermined operation is performed, so that the fuel pump unit can be attached and detached reliably and easily. .

  10A and 10B are a top view of the base 7 and a cross-sectional view taken along the line BB, respectively. The same reference numerals as those described above denote the same or equivalent parts as described above. The base 7 is manufactured by pressing a member obtained by punching a steel plate in an annular shape. In the member joining method according to the present invention, the base material 33 is provided with the bent portions 34 and 35 so that the step portion 50 for accommodating the O-ring 16 and the lid portion 13 is formed at the time of the pressing. It is characterized in that a curved portion 36 is provided in the vicinity of the peripheral edge portion 7a.

  FIG. 11 is a flowchart showing the procedure of the projection welding process according to the present embodiment. First, a projection is formed in the protrusion forming step in step S10. As described above, the projection forming step corresponds to the formation of the projection on the peripheral edge of the base 7 simultaneously with the production of the base 7, and as shown in the sub-flowchart of FIG. A punching process and the pressing process of step S21 are included. Step S11 and subsequent steps will be described later.

  FIG. 13 is a partially enlarged view of FIG. The same reference numerals as those described above denote the same or equivalent parts as described above. As described above, since the base 7 in the present embodiment is formed by punching an annular member from a smooth steel plate (step S20), the end surface (cut surface) of the peripheral edge portion 7a is the base material 33. An angle of about 90 degrees is formed with respect to the flat portion. Therefore, the protrusion 36a formed by bending the peripheral portion 7a of the base 7 and the vicinity thereof into a substantially arc shape or a predetermined angle by the curved portion 36 by the pressing (step S21) is substantially 90. It will have a sharp top. In the member joining method according to the present invention, since the projection 36a is used as a projection welding projection, a sharply shaped projection can be obtained without increasing the number of manufacturing steps by cutting or the like. .

  FIG. 14 is an explanatory view showing a state of projection welding between the base 7 and the steel plate 2a. In the projection welding, the steel plate 2a and the base 7 are arranged at a predetermined position sandwiched between the upper electrode 45 and the lower electrode 46 for projection welding, and between the upper electrode 45 and the lower electrode 46. It is executed by energizing and pressing. As shown in the flowchart of FIG. 11, in the flow of the above-described process, the member overlapping process is executed in step S11, the electrode holding process is executed in subsequent step S12, and the energizing and pressing process is executed in step S13. This is equivalent to being executed. At this time, the protrusion 36a acts as a projection, and the base 7 and the steel plate 2a are joined well. Further, in the member joining method according to the present embodiment, since the top of the protrusion 36a is sharp and the contact area with the steel plate 2a is small, a large electric resistance generated between the upper electrode 45 and the lower electrode 46 causes the current and The fever can be concentrated. As described above, according to the member joining method according to the present invention, a predetermined projection can be easily formed without increasing the number of manufacturing steps. In addition, it is possible to obtain a projection having a sharp shape suitable for large-diameter ring projection welding or the like without performing cutting or the like. Furthermore, a projection having an arbitrary shape can be easily obtained by changing a press die.

  FIG. 15 is a partially enlarged cross-sectional view of a base to which the member joining method according to the second embodiment of the present invention is applied. In the present embodiment, after the curved portion 36 is formed on the outer peripheral portion of the base 7 by pressing, the peripheral portion 7b and the protruding portion 36b are formed by cutting the member 60 on the outer side in the circumferential direction. There is. According to the member joining method according to the present embodiment, since the projection 36b is used as a projection welding projection, the angle of the tip can be arbitrarily formed according to the cut direction, and a large-diameter ring projection welding is performed. It is possible to easily obtain a projection suitable for the above.

  The shape of the base and the projection is not limited to the above-described embodiment, and various modifications can be made. Of course, the member joining method and the member joining structure according to the present invention can be applied to structures other than the fuel tank.

1 is a side view of a motorcycle to which a member joining method according to an embodiment of the present invention is applied. It is a perspective view of the fuel tank to which the member joining method concerning one embodiment of the present invention is applied. It is a side view of the fuel tank to which the member joining method concerning one embodiment of the present invention is applied. It is a schematic explanatory drawing of the attachment part of the fuel pump unit which concerns on one Embodiment of this invention. It is sectional drawing of a fuel pump unit. It is the upper side figure (a) and side view (b) of the cover part of a fuel pump unit. It is the top view (a) and side view (b) of a retainer. It is a top view in the state where the fuel pump unit was attached to the fuel tank. It is the sectional view on the AA line of FIG. It is the top view (a) of the base which concerns on one Embodiment of this invention, and the BB sectional drawing (b). It is a flowchart which shows the procedure of the projection welding process which concerns on one Embodiment of this invention. It is a sub-flowchart which shows the procedure of a protrusion formation process. FIG. 10 is a partially enlarged view of FIG. It is an outline explanatory view of projection welding to which a member joining method concerning one embodiment of the present invention is applied. It is a partial expanded sectional view of the base to which the member joining method concerning a 2nd embodiment of the present invention is applied.

Explanation of symbols

  2a ... Steel plate, 7 ... Base, 7a ... Peripheral part, 33 ... Base material, 34, 35 ... Bent part, 36 ... Curved part, 36a ... Projection part, 45 ... Upper electrode, 46 ... Lower electrode, 50 ... Step part

Claims (3)

In a member joining method for joining two members having a plate-like portion by projection welding,
A step of bending the end of the plate-like portion of the member on one side to the welding surface side to form a projection;
Superimposing the end on the plate-like part of the other member;
Sandwiching the two members with welding electrodes;
And a step of performing projection welding by energizing and pressing the two members with the electrodes. In a member joint structure for joining two members having a plate-like portion by projection welding,
A protrusion formed by curving the end of the plate-like portion of the member on one side toward the welding surface;
A member bonded structure comprising: a projection welded portion formed by energizing and pressing, wherein the projection is brought into contact with the plate-like portion of the other member. In the fuel tank adapted to receive the fuel pump unit from the opening of the fuel tank,
A substantially annular base member having a protrusion formed by curving the edge of the peripheral edge toward the weld surface by pressing;
The end part as a projection, the base member is joined to the wall surface of the fuel tank by ring projection welding,
An end portion of the fuel pump unit is fitted and fixed to the base member.

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