JP2006168436A - Fuel tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel tank of excellent durability with an upper body and a lower body fusion-bonded and integrated at high accuracy. <P>SOLUTION: The upper body and the lower body of the fuel tank are provided with a joint part installed at a position displaced outward from a general side wall of the fuel tank among opening peripheral edges and extending in a peripheral direction. Length W1 of the joint part from a pressurizing center pressurized at the time of fusion-bonding the upper side and the lower side to an opening inner peripheral end, and length W2 from the pressurizing center to an opening outer peripheral end satisfy the relationship; W1:W2=4:6-6:4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin fuel tank disposed in a vehicle.

  As a fuel tank for vehicles, what is formed with various materials, such as metal and resin, is known. Of these, the fuel tank made of a resin material is lighter in weight than that made of a metal material, and is effective in improving the fuel efficiency of the vehicle.

  By the way, these resin fuel tanks generally consist of a box-shaped upper body and a box-shaped lower body, and these two bodies are formed by welding and integration with the openings facing each other. The And the inside of the upper part box and the inside of the lower part box form a hollow space, and fuel is accommodated in this hollow part.

  In such a fuel tank, generally, the opening peripheral edge of the upper part and the opening peripheral part of the lower part are used as a joint, and the joint is welded. FIG. 6 is a cross-sectional view schematically showing a conventional fuel tank, and FIG. 7 is an enlarged cross-sectional view of a main part schematically showing how the fuel tank shown in FIG. 6 is manufactured.

  This conventional fuel tank has an upper body 100 and a lower body 200. Opening peripheral edge portions 101 and 201 of the respective split bodies are formed at the same position in the axial direction with respect to the general side wall 300. And this opening peripheral part 101,201 comprises a junction part (102,202). A rail-shaped pressing end 103 is provided at a position above the joint 102 (opening peripheral edge 101) in the upper split body 100. The pressurization end 103 is provided at a position shifted outward from the joint 102 (opening peripheral edge 101). Further, the pressurization end portion is located at a position below the joining portion 202 (opening peripheral edge portion 201) in the lower body 200 and at a position shifted outward from the joining portion 202 (opening peripheral edge portion 201). 203 is provided. The pressurizing end portions 103 and 203 are portions for applying pressure to the joint portions 102 and 202 when the upper body 100 and the lower body 200 are welded. Here, in order to weld the joints 102 and 202, the upper body 100 is pressurized from the position above the joint 102 toward the lower side, and the lower body 200 is joined from the joint 202. Also, it is necessary to pressurize from the lower position toward the upper side. However, as shown in FIG. 6, since the general side wall 300 continues to a position above the joint 102 and a position below the joint 202, the joints 102 and 202 are directly (proximity). Can not be pressed) Therefore, in the conventional fuel tank shown in FIGS. 6 and 7, the pressurizing end 103 is provided at a position above the joint 102 and shifted outward from the joint 102. A pressurization end 203 is provided at a position lower than 202 and shifted outward from the joint portion 202. The pressurization end 103 is pressurized downward and the pressurization end. The joints 102 and 202 are indirectly pressurized by pressing the part 203 upward.

  When manufacturing the conventional fuel tank shown in this figure, the joint 102 of the upper body 100 and the joint 202 of the lower body 200 are heated and melted by a hot plate. Then, the upper body 100 and the lower body 200 are welded to each other in a state where the upper body 100 and the lower body 200 face each other and the joint portions (102, 202) are in contact with each other. At this time, the jig 400 is brought into contact with the inside of the groove of the pressurizing end portions 103 and 203, and a pressure is applied to the pressurizing end portion 103 toward the lower split body 200, and the pressurizing end portion 203 is A pressure is applied in the direction of the split body 100 to weld the upper split body 100 and the lower split body 200 together.

  Here, in such a fuel tank, the pressure end 103 of the upper body 100 is pressurized in the direction of the lower body 200, and the pressure end 203 of the lower body 200 is applied in the direction of the upper body 100. When pressing, a moment in a bending direction indicated by an arrow A acts on the joints 102 and 202. This is because the pressurization center a and the joint portions 102 and 202 when the pressurization end portions 103 and 203 are pressed are arranged at positions shifted from each other. When a moment in the bending direction acts on the joint portions 102 and 202, the upper split body 100 and the lower split body 200 may not be firmly welded together. That is, in this case, the applied pressure acting on the joints 102 and 202 is different for each part, and the strength (joint strength) at which the joints (102, 202) are welded to each other is uneven for each part. Moreover, the joining part 102 of the upper part 100 and the joining part 202 of the lower part 200 may be shifted and welded, and the area of the joining part may not be sufficiently secured. In these cases, high bonding strength cannot be obtained. Since the fuel tank deforms with intake pulsation, if there is a part with low joint strength, there is a possibility of peeling from the part with low joint strength during deformation. Depending on the use conditions of the fuel tank, etc., high durability There was a possibility that the performance was not exhibited.

  Depending on the resin material constituting the upper body 100 and the lower body 200 and the welding and joining conditions, the joint 102 and the joint 202 can be joined with sufficient strength. However, the optimum resin material and welding conditions vary depending on the shape of the fuel tank and the environment in which the fuel tank is used. For this reason, it takes a lot of time to select a resin material and welding joint conditions for exhibiting sufficient joint strength, and it is difficult to easily manufacture various fuel tanks having different shapes and use environments. there were.

  On the other hand, the joint 102 (opening peripheral edge 101) of the upper split body 100 and the joint 202 (opening peripheral edge 201) of the lower split 200 are both directed outward of each split. There is also a method of extending a flange shape and applying pressure directly to the joints (102, 202) (for example, Patent Document 1). FIG. 8 shows an enlarged cross-sectional view of a main part schematically illustrating a state in which a fuel tank having a flange-like joint is manufactured.

  In the fuel tank shown in FIG. 8, when each of the split bodies is welded and joined, a joint surface of the joint portion 101 of the upper split body 100 and the joint portion 202 of the lower split body 200 that is welded to each other. The jig 400 is brought into contact with the surfaces (pressing surfaces 105, 205) facing (104, 204), respectively, and a pressure is directly applied to the joints (102, 202). For this reason, in the fuel tank shown in FIG. 8, the moment in the bending direction shown by the arrow A in FIG. There is an advantage that the joining portion 202 of the side body 200 is not easily displaced.

However, even in this case, it is difficult for the pressure applied from the jig 400 to be sufficiently transmitted to the hollow inner portion of the fuel tank (dotted line portion in FIG. 8) of the joints (102, 202). , 202), unevenness still occurs in each portion. In the portion where the applied pressure is insufficient, the joint 102 of the upper body 100 and the joint 202 of the lower body 200 are not sufficiently welded, and the upper body 100 and the lower body 200 are not welded. There is a possibility that welding and integration may not be performed with uniform bonding strength. When the upper body 100 and the lower body 200 are not welded and integrated with a uniform joint strength, the welded joints 102 and 202 have a low joint strength when the fuel tank is deformed as described above. There is a possibility of peeling from the part. Therefore, similar to the above, it takes a lot of time to select the resin material and welding joint conditions for exhibiting sufficient joint strength, and various fuel tanks with different shapes and usage environments can be easily obtained. There were problems that were difficult to manufacture.
JP 10-235737 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel tank in which an upper split body and a lower split body are welded and integrated with high accuracy and excellent in durability.

  A fuel tank of the present invention that solves the above problems is a fuel tank that is made of a resin material, and a box-shaped upper body and a box-shaped lower body are hermetically welded and integrated with the openings facing each other. The upper body part and the lower body part each have a joint part extending in the circumferential direction provided at a position shifted outward from the general side wall of the fuel tank in the opening peripheral edge part. The length W1 from the pressurization center that is pressurized when the upper body and the lower body are welded to the inner peripheral end of the opening, and the length W2 from the pressurization center to the outer peripheral end of the opening Is characterized by the relationship of W1: W2 = 4: 6 to 6: 4.

  In the fuel tank of the present invention, it is preferable that a boundary portion between the joint portion and the general side wall surface is gently curved.

  In the fuel tank of the present invention, the joint part of the upper split body and the joint part of the lower split body are provided at positions shifted outward from the general side wall of the fuel tank in the peripheral edge of the opening. For this reason, the general side wall is not continuous at a position on the upper side (or lower side) of the joint portion, and a pressure can be directly applied to the joint portion as in the conventional fuel tank shown in FIG. . Therefore, there is no problem that a moment in the bending direction acts on the joint portion when welding and integrating as in the conventional fuel tank shown in FIGS. 6 and 7 described above. For this reason, problems such as the joining portions being displaced and welded are avoided, and the upper body and the lower body are welded and integrated with high accuracy. A length W1 from the pressing center at which the joint is pressed to the opening inner peripheral end of the joint and a length W2 from the pressing center to the opening outer peripheral end of the joint is W1: By being in a relationship of W2 = 4: 6 to 6: 4, the applied pressure is uniformly applied to the entire joint. For this reason, the whole joining part is integrated with uniform joining strength, and high durability is imparted to the fuel tank.

  In addition, when the boundary portion between the joint portion and the general side wall surface is formed by being gently curved, when the fuel tank is deformed and a bending load is applied to the wall surface of the fuel tank, stress is applied to the curved portion. scatter. Therefore, stress does not concentrate on the portion where the joints are welded to each other, and problems such as separation of the joints welded to each other are avoided. For this reason, further excellent durability is imparted to the fuel tank.

  The fuel tank of the present invention can be formed in various shapes according to the vehicle. It can also be comprised only from the bipartite of an upper part body and a lower part body, and you may comprise from three or more parts including other parts. As the resin material, a general resin material used for a fuel tank represented by HDPE (high density polyethylene) or the like may be used. The upper side body and the lower side body may be formed of the same resin material or different resin materials. In the case of forming from different resin materials, materials having high compatibility with each other may be selected.

Hereinafter, a fuel tank of the present invention will be described with reference to the drawings.

Example 1
FIG. 1 is a cross-sectional view schematically showing the fuel tank of this embodiment, and FIG. 2 is an enlarged cross-sectional view showing a main part of the fuel tank shown in FIG.

  The fuel tank of this embodiment is composed of two bodies, an upper body 1 and a lower body 2. The upper body 1 and the lower body 2 are each formed in a box shape, and the openings have substantially the same diameter. A lower tank 2 is provided with a sub-tank 6 made of a spiral standing wall from the lower bottom 20 toward the hollow interior 5. A fuel pump (not shown) is attached to the upper body 1 at a position facing the sub tank 6 of the lower body 2. Both the upper body 1 and the lower body 2 are made of a resin material having a high fuel barrier property.

  The upper body 1 and the lower body 2 are hermetically welded and integrated with the openings facing each other. And the general side wall 3 which is a side wall of each division is each extended in the substantially perpendicular direction. The joining portion 8 constituting a part of the opening peripheral portion 10 of the upper body 1 and the joining portion 9 constituting a part of the opening peripheral portion 20 of the lower body 2 are also formed to have substantially the same diameter. The joints 8 and 9 of each split body are provided in the circumferential direction along the periphery of the opening. Of the joint portion 8 (9), the joint surface 80 (90) that joins the joint portion 9 (8) of another split body extends substantially horizontally. In other words, the joints 8 and 9 of each of the split bodies are formed in a substantially annular shape and are arranged at a position closer to the opening end than the general side wall 3.

  In the fuel tank of the present embodiment, the joint portion 8 of the upper split body 1 and the joint portion 9 of the lower split body 2 are provided at positions shifted outward from the general side wall 3 of the fuel tank. That is, the opening inner peripheral side end portions 81 and 91 that are the portions located on the inner peripheral side of the joints 8 and 9 are outside the inner peripheral side surface 30 that is the surface on the inner peripheral side of the general side wall 3. It is arranged on the side.

  The general side wall 3 and the joints 8 and 9 are connected to each other by a slant wall 31, and the boundary part between the slant wall 31 and the general side wall 3 and the boundary part between the slant wall 31 and the joint parts 8 and 9 are each It is gently curved and connected. For this reason, the boundary part of the junction parts 8 and 9 and the general side wall 3 is provided in the gently curved shape, and connects the junction parts 8 and 9 and the general side wall 3 smoothly. Of these, the boundary portions 15 and 25 between the inclined wall 31 and the general side wall 3 are curved with the arc surface facing the inner peripheral side of the opening, and the boundary portions 16 and 26 between the inclined wall 31 and the joint portions 8 and 9 are arc surfaces. Is curved toward the outer periphery of the opening.

  Of the joint portions 8 and 9 of the respective split bodies, substantially annular groove-shaped jig grooves 18 and 28 are provided on the pressing surfaces 17 and 27 facing the joint surfaces 80 and 90. Each of the jig grooves 18 and 28 is formed to have a slightly larger diameter than the distal end portion of the pressing jig 4, and outer peripheral walls 19 and 29 that are outer peripheral side groove walls extend substantially vertically. The outer peripheral walls 19 and 29 are portions for positioning the jig 4 when the jig 4 is brought into contact with the inside of the jig grooves 18 and 28. In the fuel tank of the present embodiment, the portions of the joints 8 and 9 that are at the same position in the vertical direction with respect to the center of the jig grooves 18 and 28 are the upper body 1 and the lower body. It becomes a central portion to be pressed when the body 2 is welded, that is, a pressing center 7.

  Moreover, the opening outer peripheral side edge parts 82 and 92 which are the parts located in the outer peripheral side of the joints 8 and 9 have shapes in which the respective open end side parts are gently recessed toward the inner peripheral side of the opening. Yes.

  In the fuel tank of the present embodiment, the length W1 from the pressurization center to the opening inner peripheral end portions 81 and 91 and the length W2 from the pressurization center to the opening outer peripheral end portions 82 and 92 are the same length. W1 and W2 satisfy the relationship of W1: W2 = 4: 6 to 6: 4.

  When manufacturing the fuel tank of the present embodiment by welding and integrating the upper body 1 and the lower body 2, first, the jig groove 18 of the upper body 1 and the jig groove of the lower body 2 are used. 28, the jig 4 is inserted into each, and the joining surface 80 of the upper part 1 and the joining surface 90 of the lower part 2 are both heated by a hot plate and melted. Then, with the joint 8 of the upper body 1 and the joint 9 of the lower body 2 facing each other, the joint surfaces 80 and 90 are brought into contact with each other to press the jig 4 toward the other jig 4. Then, the joint portions 8 and 9 are pressurized. When the joints 8 and 9 are pressurized, melted portions of the joints 8 and 9 are compatible with each other. Then, the fuel tank of the present embodiment in which the upper part 1 and the lower part 2 are welded and integrated is manufactured by cooling and solidifying the compatible parts of the joints 8 and 9.

  In the fuel tank of the present embodiment, the joint 8 of the upper split 1 and the joint 9 of the lower split 2 are provided at positions shifted outward from the general side wall 3, respectively. The pressing force can be applied directly to the portions 8 and 9. Therefore, when welding and integrating, no moment in the bending direction acts on the joints 8 and 9, and the upper body 1 and the lower body 2 are welded and integrated with high accuracy.

  And the length W1 from the pressing center to the opening inner peripheral side end portions 81, 91 and the length W2 from the pressing center to the opening outer peripheral end portions 82, 92 of the joint portions 8, 9 are the same length. Since the relationship of W1: W2 = 4: 6 to 6: 4 is satisfied, the opening inner peripheral side end portions 81 and 91 and the opening outer peripheral side end portions 82 and 92 of the joint portions 8 and 9 are arranged. The same amount of pressure is applied. Therefore, the entire joints 8 and 9 are integrated with a uniform joint strength, and high durability is imparted to the fuel tank.

  Further, in the fuel tank of this embodiment, the boundary portion between the joint portions 8 and 9 and the surface of the general side wall 3 is gently curved. Therefore, when the fuel tank is deformed, for example, bending in the direction of arrow B in FIG. When a load is applied, the stress is distributed to the curved portions 15 and 16. Therefore, it is avoided that stress concentrates on the portion where the joint portions 8 and 9 are welded. For this reason, in the fuel tank of the present embodiment, problems such as separation of the welded portions 8 and 9 welded to each other are avoided, and very excellent durability is imparted to the fuel tank.

  In the fuel tank of this embodiment, a recess is provided in advance in the opening end side portion of the opening outer peripheral side end portions 82 and 92 of each joint portion 8 and 9. Moreover, the opening inner peripheral side end portions 81 and 91 of the joint portions 8 and 9 are arranged on the outer side of the inner peripheral side surface 30 of the general side wall 3, and the opening inner peripheral end portions of the joint portions 8 and 9 are disposed. 81 and 91 are also recessed. For this reason, a portion (so-called welding burr 32) where the molten resin overflowed when welding the joint is solidified does not protrude inside or outside the fuel tank, and the welding burr 32 is disposed inside the fuel tank. There is no interference with various devices arranged adjacent to the outside of the fuel tank or the fuel tank.

  Furthermore, in the fuel tank of this embodiment, the portion of the joints 8 and 9 that is located at the same position in the vertical direction with respect to the center of the jig grooves 18 and 28 is the center of pressurization. Is not limited to this, and is appropriately determined depending on the shape of the joint, jig groove, jig, etc., the direction of pressurization when the upper body and the lower body are welded, and the like. In general, the point of action where the pressure applied during welding acts on the joint is the center of pressurization.

(Example 2)
The fuel tank of Example 2 is the same as that of Example 1 except that W1 and W2 have a relationship of W1: W2 = 6: 4. FIG. 3 shows an enlarged cross-sectional view of a main part schematically showing a state in which the fuel tank of this embodiment is manufactured.

  In the fuel tank of this embodiment, the protruding length of the joints 8 and 9 to the outside is smaller than that of the first embodiment. For this reason, the length W1 from the pressing center to the opening inner peripheral end portions 81 and 91 and the length W2 from the pressing center to the opening outer peripheral end portions 82 and 92 are W1: W2 = 6: 4. It has become a relationship. Therefore, the applied pressure acting on the opening inner peripheral side end portions 81 and 91 is slightly smaller than the applied pressure acting on the opening outer peripheral end portions 82 and 92.

  However, since W1 and W2 satisfy the relationship of W1: W2 = 6: 4 to 4: 6, and W1 and W2 can be said to have substantially the same length, the opening inner peripheral end portions 81 and 91 and the opening outer peripheral end The applied pressure acting on the portions 82 and 92 is not substantially different. Therefore, also in the fuel tank of the present embodiment, the entire joints 8 and 9 are integrated with substantially uniform joining strength, and high durability is imparted to the fuel tank.

  Also in the fuel tank of this embodiment, since the boundary portion between the joints 8 and 9 and the general side wall 3 is gently curved, a bending load is applied to the wall surface of the fuel tank similarly to the fuel tank of the first embodiment. When applied, the stress is dispersed in the curved portion. For this reason, even in the fuel tank of the present embodiment, problems such as separation of the joints 8 and 9 welded to each other can be avoided more reliably, and further excellent durability can be imparted to the fuel tank.

  In the fuel tank of this embodiment, the length from the center of pressurization to the opening outer peripheral side end portions 82 and 92 is slightly shorter, so the outer diameter of the fuel tank is reduced and the fuel tank is made smaller. There are advantages you can do.

(Example 3)
The fuel tank of Example 2 is the same as that of Example 1 except that W1 and W2 have a relationship of W1: W2 = 4: 6. A cross-sectional view schematically showing the fuel tank of this embodiment is shown in FIG.

  The fuel tank of the present embodiment has a longer protruding length of the joints 8 and 9 than that of the first embodiment, and the length from the center of pressurization to the end portions 81 and 91 on the inner peripheral side of the opening. The length W1 and the length W2 from the center of pressurization to the opening outer peripheral side ends 82 and 92 have a relationship of W1: W2 = 4: 6. For this reason, the pressurizing force acting on the opening outer peripheral side end portions 82 and 92 is slightly smaller than the pressurizing force acting on the opening inner peripheral end portions 81 and 91.

  However, since W1 and W2 satisfy the relationship of W1: W2 = 6: 4 to 4: 6, and W1 and W2 can be said to have substantially the same length, the opening inner peripheral end portions 81 and 91 and the opening outer peripheral end The applied pressure acting on the portions 82 and 92 is not substantially different. Therefore, also in the fuel tank of the present embodiment, as in the first and second embodiments, the entire joints 8 and 9 are integrated with a substantially uniform joint strength, and high durability is imparted to the fuel tank. The

  In the fuel tank of this embodiment, the length from the center of pressurization to the opening inner peripheral side end portions 81 and 91 is slightly short, and the protruding length of the joint portions 8 and 9 to the outside is large. Therefore, the amount of the welding burr 32 protruding into the hollow inside of the fuel tank is reduced, and there is an advantage that interference of the welding burr 32 to various devices arranged in the fuel tank can be avoided more reliably. .

Example 4
The fuel tank of Example 4 is the same as that of Example 1 except for the shape of the boundary portion between the joints 8 and 9 and the general side wall 3. In the fuel tank of Example 4, W1 and W2 have a relationship of W1: W2 = 1: 1. FIG. 5 shows an enlarged cross-sectional view of a main part schematically showing a state in which the fuel tank of this embodiment is manufactured.

  In the fuel tank of the present embodiment, the boundary portion between the joint portions 8 and 9 and the general side wall 3 is not gently curved like the fuel tanks of the first to third embodiments. For this reason, unlike the fuel tanks of Examples 1 to 3, the effect that stress is distributed to the curved portion is not exhibited.

  However, the relationship between W1 and W2 is W1: W2 = 1: 1, and in order to satisfy the relationship of W1: W2 = 4: 6 to 6: 4, joining is performed similarly to the fuel tanks of Examples 1 to 3. The entire portions 8 and 9 are integrated with substantially uniform bonding strength, and high durability is imparted to the fuel tank.

2 is a cross-sectional view schematically showing a fuel tank of Example 1. FIG. It is a principal part expanded sectional view which represents typically a mode that the fuel tank of Example 1 is manufactured. It is a principal part expanded sectional view which represents typically a mode that the fuel tank of Example 2 is manufactured. It is a principal part expanded sectional view which represents a mode that the fuel tank of Example 3 is manufactured typically. It is a principal part expanded sectional view which represents a mode that the fuel tank of Example 4 is manufactured typically. It is sectional drawing which represents the conventional fuel tank typically. It is a principal part expanded sectional view which represents a mode that the conventional fuel tank is manufactured typically. It is a principal part expanded sectional view which represents a mode that the conventional fuel tank is manufactured typically.

Explanation of symbols

1: Upper split 2: Lower split 10: Upper peripheral edge of upper split 8: Upper split joint 20: Lower split peripheral edge 9: Lower split joint 3: General Side wall 81: Opening inner peripheral end of upper split 91: Opening inner peripheral end of lower split 7: Pressure center

Claims (2)

A fuel tank made of a resin material, wherein a box-shaped upper body and a box-shaped lower body are hermetically welded and integrated with the openings facing each other,
The upper body and the lower body each have a joint extending in the circumferential direction provided at a position shifted outward from the general side wall of the fuel tank in the opening periphery.
Of the joint, a length W1 from the pressurization center to the inner end of the opening that is pressurized when welding the upper split body and the lower split body, and the outer periphery of the opening from the pressurization center A fuel tank characterized in that the length W2 to the side end is in a relationship of W1: W2 = 4: 6 to 6: 4.   The fuel tank according to claim 1, wherein a boundary portion between the joint portion and the general side wall surface is gently curved.

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