Manufacturing device of fuel tank and manufacturing method of fuel tank

Abstract

This invention provides a fuel tank manufacturing apparatus and a fuel tank manufacturing method, which can reduce the production cost and shorten the production cycle of manufacturing fuel tanks with ribs. The fuel tank manufacturing apparatus having a forming mold and a cooling mold is characterized in that: the forming mold has a raised strip on the forming surface, forming a one-time molded article while forming a raised rib-shaped part (21) with a concave part on the outer surface, and the cooling mold (40) cools the one-time molded article while flattening the raised rib-shaped part (21) by cooling blow molding pressure, deforming it into a rib-shaped part (3).

Description

Technical Field

[0001] This invention relates to an apparatus for manufacturing a fuel tank and a method for manufacturing a fuel tank. Technical Background

[0002] Patent Document 1 discloses a blow molding die with a pair of opposing sliders. In a method for manufacturing a fuel tank using this blow molding die, the pair of sliders are used to press the preform into the die, fusing the opposing preforms together. After the pair of sliders are removed, the die is deformed using blow molding pressure to form ribs.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: U.S. Patent Application Publication No. 2016 / 0052187 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In the manufacturing method of Patent Document 1, a pair of sliders need to be set on the blow molding die in order to form ribs inside the fuel tank. Therefore, while the structure and control of the blow molding die become more complex, problems such as increased cost and longer production cycle also arise.

[0008] This invention was conceived in response to this viewpoint, and its technical problem lies in reducing the production cost of manufacturing fuel tanks with ribs and shortening their production cycle.

[0009] Technical solutions for solving technical problems

[0010] To solve the above-mentioned technical problems, the present invention provides a manufacturing apparatus for a fuel tank having a forming mold and a cooling mold, characterized in that: the forming mold has a raised rib portion on the forming surface, forming a one-time molded product while forming the raised rib-shaped portion into a concave portion on the outer surface; the cooling mold cools the one-time molded product while flattening the raised rib-shaped portion by cooling blow molding pressure, deforming it into a rib-like portion.

[0011] Furthermore, the present invention is characterized by including a forming process in which a convex ridge-shaped portion is formed on an outer surface having a recess while forming a primary molded article using a forming mold, and a cooling process in which the primary molded article formed in the forming process is placed in a cooling mold and subjected to cooling blow molding, wherein the primary molded article is cooled while the convex ridge-shaped portion is flattened by cooling blow molding pressure to deform it into a rib-like portion.

[0012] According to the present invention, complex structures such as sliders are not required in the forming mold, and rib-shaped portions can be formed within the fuel tank using a simple structure. Furthermore, since sliders are not used, the process of pressing or removing sliders into or out of the fuel tank during forming to create the rib-shaped portions is eliminated. This reduces production costs and shortens the production cycle. Additionally, compared to convex ridge-shaped portions, the rib-shaped portions occupy a smaller volume within the fuel tank, thus preventing a reduction in the fuel tank's capacity.

[0013] In addition, the cooling mold is preferably provided with a negative pressure section, through which negative pressure is generated on the convex ridge-shaped portion from the outer surface side of the one-time molded article, so as to deform the sidewalls of the convex ridge-shaped portion in such a way that they come closer to each other.

[0014] In addition, it is preferable to provide a negative pressure part on the cooling mold. During the cooling process, the negative pressure part generates negative pressure on the convex ridge-shaped part from the outer surface side of the one-time molded article, causing the sidewalls of the convex ridge-shaped part to deform and approach each other.

[0015] According to the present invention, the forming accuracy of the ribs can be improved.

[0016] In addition, in the cooling mold, it is preferable to deform the convex ridge portion into the rib portion at a temperature lower than the melting point of the one-piece molded article and at a temperature that allows for deformation.

[0017] Furthermore, in the cooling process, it is preferable to deform the convex ridge portion into the rib portion at a temperature below the melting point of the one-piece molded article and at a temperature that allows for deformation.

[0018] In this way, the deformation from the convex ridge shape to the rib shape can be optimized.

[0019] The effects of the invention

[0020] According to the present invention, the production cost of manufacturing fuel tanks with ribs can be reduced and the production cycle can be shortened. Attached Figure Description

[0021] Figure 1 is a perspective view of the interior of the fuel tank according to the first embodiment from above.

[0022] Figure 2 is a cross-sectional view of the forming mold of the fuel tank manufacturing apparatus according to the first embodiment.

[0023] Figure 3 is a cross-sectional view of the cooling mold of the fuel tank manufacturing apparatus according to the first embodiment.

[0024] Figure 4 is a cross-sectional view showing the blank preparation process of the fuel tank manufacturing method according to the first embodiment.

[0025] Figure 5 is a cross-sectional view showing the forming process of the manufacturing method of the fuel tank according to the first embodiment.

[0026] Figure 6 is a cross-sectional view showing the demolding process (after forming) of the fuel tank manufacturing method according to the first embodiment.

[0027] Figure 7 is a cross-sectional view showing the setup process of the fuel tank manufacturing method according to the first embodiment.

[0028] Figure 8 is a cross-sectional view showing the cooling process of the fuel tank manufacturing method according to the first embodiment.

[0029] Figure 9 is a cross-sectional view showing the demolding process (after cooling) of the fuel tank manufacturing method according to the first embodiment.

[0030] Figure 10 is a cross-sectional view showing the forming process of the fuel tank manufacturing method according to the second embodiment.

[0031] Figure 11 is a cross-sectional view showing the cooling process of the fuel tank manufacturing method according to the second embodiment. Detailed Implementation

[0032] The manufacturing apparatus and method for a fuel tank according to the first embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, the following embodiments are merely examples and are not intended to limit the present invention. Additionally, the various embodiments can be appropriately combined.

[0033] [First Implementation Method]

[0034] <Fuel Tank>

[0035] Figure 1 is a perspective view of the interior of the fuel tank according to the first embodiment from above. The fuel tank T shown in Figure 1 is made of resin and can store fuels such as gasoline. It can be mounted on vehicles such as automobiles, motorcycles, and ships. The fuel tank T is wide and thinner in the vertical direction. The fuel tank T is formed of a thermoplastic resin including a barrier layer.

[0036] The fuel tank T has a fuel tank body 1, a pump mounting hole 2, and ribs 3, 3. The pump mounting hole 2 is cylindrical and is formed by penetrating the top surface 1b of the fuel tank body 1. A pump (not shown) is installed in the pump mounting hole 2 to draw fuel out of the fuel tank T.

[0037] The ribs 3 and 3 are plate-like portions that are erected on the bottom surface 1a of the fuel tank body 1 and extend upwards. There are no particular limitations on the shape of the ribs 3 and 3, but in this embodiment, they are rectangular in both the side and top views. The ribs 3 and 3 improve the deformation resistance and strength of the fuel tank T and can dampen waves during fuel oscillations. Furthermore, the fuel tank body 1 may also have other internal components.

[0038] <Fuel Tank Manufacturing Equipment>

[0039] The fuel tank manufacturing apparatus according to this embodiment comprises a forming mold 10 shown in FIG2 and a cooling mold 40 shown in FIG3. The forming mold 10 and the cooling mold 40 are electrically connected to a control unit (not shown) and can operate according to signals from the control unit to manufacture the fuel tank T.

[0040] As shown in Figure 2, the forming mold 10 has a first forming mold 10a and a second forming mold 10b. The first forming mold 10a is provided with a forming surface 11a, a hole forming surface 12, and a blow molding needle 13. The forming surface 11a is the part used to form the fuel tank body 1. The hole forming surface 12 is the part used to form the pump mounting hole 2. The blow molding needle 13 is a conduit used to supply air during forming.

[0041] The second forming mold 10b is disposed opposite to the forming surface 11a. The second forming mold 10b is provided with the forming surface 11b and the raised portions 14, 14. The forming surface 11b is the portion used to form the fuel tank body 1. The raised portions 14 extend from the forming surface 11b toward the first forming mold 10a and are the portion used to form the raised ridge shape portion 21 described later. The cross-section of the raised portions 14 is trapezoidal and plate-shaped. The raised portions 14 widen at an angle from the front end side to the base end side so that the primary molded product 30 described later can be ejected (separated) from the second forming mold 10b during demolding.

[0042] As shown in Figure 3, the cooling mold 40 has a first cooling mold 40a and a second cooling mold 40b. The first cooling mold 40a is provided with an opposing surface 41a, a hole opposing surface 42, and a blow molding needle 43. The opposing surface 41a is the portion opposite to the outer surface of the fuel tank body 1. The hole opposing surface 42 is the portion opposite to the pump mounting hole 2. The blow molding needle 43 is a conduit for supplying air during cooling.

[0043] The second cooling mold 40b is disposed opposite to the opposing surface 41a. The second cooling mold 40b is provided with the opposing surface 41b and a plurality of connecting holes 45. The opposing surface 41b is the portion opposite to the outer surface of the fuel tank body 1. The connecting holes 45 are holes that communicate with the outside from the opposing surface 41b. The connecting holes 45 include a suction device (not shown) and constitute a negative pressure section. The negative pressure section is the portion that generates negative pressure from the outer surface of the fuel tank body 1 towards the convex ridge-shaped portion 21 (described later) to deform the sidewalls in a manner that brings them closer together. In other words, the negative pressure section is a device that promotes the deformation of the convex ridge-shaped portion 21. The first cooling mold 40a and the second cooling mold 40b are substantially the same in shape as the first forming mold 10a and the second forming mold 10b, except for the presence or absence of the convex ridge portion 14 and the connecting holes 45.

[0044] <Manufacturing Method of Fuel Tank>

[0045] The manufacturing process of a fuel tank involves the following steps: preform preparation, forming, demolding (after forming), setting, cooling, and demolding (after cooling).

[0046] As shown in Figure 4, the preform arrangement process involves placing sheet preforms 20, 20 between the first forming mold 10a and the second forming mold 10b. The preform 20 is a thermoplastic resin including a barrier layer, and is the material constituting the fuel tank body 1. The preform 20 can be deformed (formed) at a temperature that is the same as or higher than the melting point of the material. Furthermore, the preform 20 can be cylindrical.

[0047] As shown in Figure 5, the forming process is a blow molding process using forming mold 10. In the forming process, the first forming mold 10a and the second forming mold 10b are closed, and air is supplied to the interior through the blow molding needle 13. Through the forming process, due to the blow molding pressure acting from the inside to the outside of the preform 20, the preform 20 is transferred to the forming surfaces 11a and 11b, the hole forming surface 12, and the protruding part 14, thereby being formed. The protruding parts 14 form the convex ridge-shaped parts 21. The cross-section of the convex ridge-shaped part 21 is trapezoidal and plate-shaped.

[0048] As shown in Figure 6, the demolding process (after molding) is the process of separating the first molding die 10a and the second molding die 10b. This results in a hollow, one-piece molded article 30. Recesses 31, 31 are formed on the outer surface of the one-piece molded article 30 at positions corresponding to the convex ridge-shaped portions 21, 21.

[0049] As shown in Figure 7, the setting process involves placing the one-piece molded article 30 inside the first cooling mold 40a and the second cooling mold 40b. The outer surface of the one-piece molded article 30 is positioned opposite to the opposing surfaces 41a, 41b and the opposing surface 42 of the hole. A space is formed between the opposing surface 41b and the recess 31.

[0050] As shown in Figure 8, the cooling process is a process of cooling blow molding using a cooling mold 40. In the cooling process, air is supplied to the interior of the primary molded part 30 through the blow molding needle 43. The temperature of this air can be appropriately set; it can be the same as or lower than the temperature during blow molding. At this time, the temperature of the primary molded part 30 is lower than the melting point of the primary molded part (preform) 30 and is a temperature at which deformation is possible. During the cooling process, since the cooling blow molding pressure acts from the interior to the exterior of the primary molded part 30, the rib-shaped part 3 can be formed by pressing the sidewalls constituting the convex rib-shaped part 21 towards each other (refer to the hollow arrow). In other words, the height of the convex rib-shaped part 21 remains approximately constant, while the sidewalls are flattened towards each other in the approaching direction, thereby forming the rib-shaped part 3. Furthermore, since air is drawn from the recess 31 through the connecting hole 45 of the negative pressure section during cooling blow molding, the sidewalls of the convex rib-shaped part 21 are more easily deformed towards each other in the approaching direction.

[0051] As shown in Figure 9, the demolding process (after cooling) is the process of separating the first cooling mold 40a and the second cooling mold 40b. This forms the secondary molded product 60. Finally, by removing burrs, the fuel tank T is formed.

[0052] According to the fuel tank manufacturing apparatus and method described above in this embodiment, there is no need to provide complex structures such as sliders on the forming mold 10, and ribs 3, 3 can be formed in the fuel tank T with a simple structure. Furthermore, since sliders are not used, the process of pressing or removing sliders into the fuel tank T (one-piece molded product 30) to form the ribs 3, 3 during forming is omitted. This reduces production costs and shortens the production cycle. In addition, compared to the convex ridge-shaped portions 21, 21, the ribs 3, 3 occupy a smaller volume in the fuel tank T, thus preventing a decrease in the capacity of the fuel tank T.

[0053] Furthermore, since the cooling mold 40 has a negative pressure section, the deformation of the convex ridge-shaped section 21 can be promoted. As a result, the forming accuracy of the rib-shaped section 3 can be improved.

[0054] Furthermore, in the cooling mold 40, at a temperature below the melting point of the one-piece molded article 30 and at which deformation is possible, the convex ridge-shaped portion 21 is deformed into a rib-shaped portion 3. This allows for optimization of the deformation from the convex ridge-shaped portion 21 to the rib-shaped portion 3.

[0055] [Second Implementation]

[0056] Next, the fuel tank manufacturing apparatus and fuel tank manufacturing method according to the second embodiment will be described. The main difference between the second embodiment and the first embodiment is that the rib-shaped portion 3 is provided on the bottom surface of the fuel tank body 1, and the rib-shaped portion 4 is provided on the top surface of the fuel tank body 1, thereby connecting the two. When describing the second embodiment, descriptions that are repeated in the first embodiment will be omitted, and only the differences will be described.

[0057] <Fuel Tank Manufacturing Equipment>

[0058] Figure 10 is a cross-sectional view showing the forming process of the fuel tank manufacturing method according to the second embodiment.

[0059] Figure 11 is a cross-sectional view showing the cooling process of the fuel tank manufacturing method according to the second embodiment. The fuel tank manufacturing apparatus according to this embodiment includes a forming mold 10A and a cooling mold 40A.

[0060] As shown in Figure 10, the molding die 10A includes a first molding die 10a and a second molding die 10b. The first molding die 10a has a forming surface 11a, a hole forming surface 12, a blow molding needle 13, and raised portions 15, 15. The raised portions 15 extend from the forming surface 11a toward the second molding die 10b and are used to form the raised ridge shape portion 22 (described later). The cross-section of the raised portion 15 is trapezoidal and plate-shaped. Furthermore, the raised portions 15, 15 are positioned opposite to raised portions 14, 14, respectively. On the other hand, the second molding die 10b is the same as in the first embodiment.

[0061] As shown in Figure 11, the cooling mold 40A includes a first cooling mold 40a and a second cooling mold 40b. The first cooling mold 40a has a facing surface 41a, a hole facing surface 42, a blow molding needle 43, and a connecting hole 45. The connecting hole 45 is a hole that communicates with the outside from the facing surface 41a. The connecting hole 45 includes a suction device (not shown) and constitutes a negative pressure section. The negative pressure section is the part that generates negative pressure from the outer surface of the fuel tank body 1 towards the convex ridge-shaped portion 22, causing its sidewalls to deform in a manner that brings them closer together. In other words, the negative pressure section is a device that promotes the deformation of the convex ridge-shaped portion 22. On the other hand, the second cooling mold 40b is the same as in the first embodiment.

[0062] <Manufacturing Method of Fuel Tank>

[0063] In the fuel tank manufacturing method according to this embodiment, the following steps are performed: preform preparation, forming, demolding (after forming), setting, cooling, and demolding (after cooling). Furthermore, the preform preparation, demolding (after forming), setting, and demolding (after cooling) steps are the same as in the first embodiment.

[0064] As shown in Figure 10, the forming process is a blow molding process using forming mold 10A. In the forming process, the first forming mold 10a and the second forming mold 10b are closed, and air is supplied to the interior through the blow molding needle 13. Through the forming process, due to the blow molding pressure acting from the inside to the outside of the preform 20, the preform 20 is transferred to the forming surfaces 11a and 11b, the hole forming surface 12, and the protruding portions 14 and 15, thereby being formed. The forming process forms the protruding ridge shapes 21, 21, 22, and 22. In addition, the opposing protruding ridge shapes 21 and 22 abut against each other.

[0065] As shown in Figure 11, the cooling process is a process of cooling blow molding using a cooling mold 40A. In the cooling process, air is supplied to the interior of the primary molded part 70 through the blow molding needle 43. The temperature of this air can be appropriately set; it can be the same as or lower than the temperature during blow molding. At this time, the temperature of the primary molded part 70 is lower than the melting point of the primary molded part (preform) and is at a temperature where deformation is possible. During the cooling process, since the cooling blow molding pressure acts from the interior to the exterior of the primary molded part 70, the ribs 3 and 4 can be formed by pressing the sidewalls constituting the convex rib-shaped portions 21 and 22 towards each other (refer to the hollow arrow). Furthermore, since air is drawn from the outside of the primary molded part 70 through the negative pressure section during cooling blow molding, the sidewalls of the convex rib-shaped portions 21 and 22 are more easily deformed towards each other.

[0066] The second embodiment described above achieves roughly the same effects as the first embodiment. In particular, according to the second embodiment, complex structures such as sliders are not required on the forming mold, allowing for the formation of opposing ribs 3 and 4 using a simple structure. By abutting the ribs 3 and 4 together, the strength and deformation resistance of the fuel tank T can be further improved.

[0067] Although embodiments of the present invention have been described above, appropriate design changes can be made without altering the spirit of the invention. For example, the negative pressure portion can be omitted as long as the rib-shaped portion can be formed. Furthermore, in the second embodiment, the rib-shaped portions 3 and 4 are designed to abut against each other, but they can also be separated.

[0068] Explanation of reference numerals in the attached figures

[0069] T fuel tank

[0070] 1. Fuel tank body

[0071] 1a bottom surface

[0072] 1b top surface

[0073] 2 Pump mounting holes

[0074] 3rd and 4th ribs

[0075] 10 forming molds

[0076] 11a, 11b forming surfaces

[0077] 13 blow molding needles

[0078] 14 convex parts

[0079] 15 convex part

[0080] 20-type billet

[0081] 21, 22 convex ridge-shaped parts

[0082] 30, 70 One-piece molded products

[0083] 31 recess

[0084] 40 Cooling Mold

[0085] 41a and 41b opposite faces

[0086] 43 blow molding needles

Claims

1. A manufacturing apparatus for a fuel tank having a forming mold and a cooling mold, characterized in that: The forming mold has a raised section on the forming surface, configured to form a one-time molded article by supplying air into the interior of the preform including the barrier layer, and simultaneously forming the raised ridge shape into a one-time molded article with a recess on the outer surface. The cooling mold has a negative pressure section that generates negative pressure on the convex rib-shaped portion. By supplying air into the interior of the primary molded article and generating negative pressure on the convex rib-shaped portion from the outer surface of the primary molded article through the negative pressure section, the primary molded article is cooled while the convex rib-shaped portion is flattened and deformed into a rib-like portion by cooling blow molding pressure.

2. The fuel tank manufacturing apparatus according to claim 1, characterized in that: The cooling mold deforms the convex ridge-shaped parts by drawing air from the outer surface of the one-piece molded article through the negative pressure section while performing cooling blow molding, so that the sidewalls of the convex ridge-shaped parts come closer to each other.

3. The fuel tank manufacturing apparatus according to claim 1 or claim 2, characterized in that: In the cooling mold, at a temperature below the melting point of the primary molded article and at which deformation is possible, the convex ridge-shaped portion is deformed into the rib-shaped portion.

4. A method for manufacturing a fuel tank, characterized in that: The manufacturing method includes a forming process in which a convex-shaped portion is formed into a molded article having a recess on its outer surface by supplying air into the interior of a preform including a barrier layer using a forming mold. A cooling process is performed by placing the primary molded article formed in the molding process into a cooling mold having a negative pressure part that generates negative pressure on the convex ridge-shaped part and performing cooling blow molding. In the cooling process, air is supplied to the interior of the primary molded article, and negative pressure is generated from the outer surface of the primary molded article toward the convex rib-shaped portion through the negative pressure section. Accordingly, the primary molded article is cooled while the convex rib-shaped portion is flattened and deformed into a rib-like portion by cooling blow molding pressure.

5. The method for manufacturing a fuel tank according to claim 4, characterized in that: In the cooling process, air is drawn from the outer surface of the one-piece molded article through the negative pressure section while cooling blow molding is performed, so that the sidewalls of the convex ridge-shaped parts are deformed in such a way that they come closer to each other.

6. The method for manufacturing a fuel tank according to claim 4 or claim 5, characterized in that: During the cooling process, at a temperature below the melting point of the one-piece molded article and at which deformation is possible, the convex ridge-shaped portion is deformed into the rib-shaped portion.

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