JP2016101660A - Method for forming opening part of blow molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming an opening part of a blow molding by which an opening part of an outer wall of a fuel tank or the like can be easily cut off and easily forming the opening part.SOLUTION: A blow molding mold 20 is provided with a cutting space part 29 between an opening cylindrical part molding part 24 and a cut part holding part 22, and is provided with an opening part cutting blade 27 slidable through the cutting space part 29. The opening part all-around blade 27 is provided with an opening part cutting blade sliding space part 28c, and a gap part open/close member 30 capable of opening/closing the opening part cutting blade sliding space part. The surface where the opening part cutting blade sliding space part 28c and the space part opening/closing member 30 are abutted, is formed as an inclined surface. The inclined surface of the space part opening/closing member 30 slides to the inclined surface of the opening part cutting blade sliding space part 28c to be firmly attached. The opening part cutting blade sliding space part 28c is blocked with the space part opening/closing member 30 to make a parison 5 firmly attach thereto, the opening cutting blade 27 is slid, and the parison 5 of the opening cut part 17 is cut off with a cutting blade tip end part 27b.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for forming an opening of a blow molded product formed of a thermoplastic synthetic resin.

Conventionally, the structure of a hollow body such as a fuel tank for automobiles has been made of metal. However, in recent years, the weight of the vehicle is reduced, rust is not generated, and it is easy to mold into a desired shape. For example, those made of thermoplastic synthetic resin have been used.
For the production of a hollow body made of a thermoplastic synthetic resin, a blow molding method has been often used because of the ease of molding the hollow body. In the blow molding method, a melted thermoplastic synthetic resin member parison is formed into a cylindrical shape and extruded from a die of a blow molding machine. Was producing blow molded products.

In this blow molded product, as shown in FIG. 1, an opening 110 is formed for taking in and out a component to be mounted inside the hollow body. The opening 110 is formed by integrally forming the opening 110 at the same time that the blow molded article 101 is formed by blow molding.
For example, as shown in FIG. 17, there is a method of forming the opening 110 by providing a slidable rotary blade 130 on the blow molding die 120 and cutting the outer wall 102 of the blow molded product 101 (for example, a patent). Reference 1).

As shown in FIGS. 17 to 19, the opening 110 is formed by forming a cutting edge 133 at the tip of the rotary blade 130, projecting the cutting edge 133 slightly into the cavity 126 and positioning the cutting edge 131 in advance. Blow molding is performed in a state of entering the inside of the mold surface of the blow molding die 120, and the resin parison is brought into close contact with the cutting edge 131 to form the blow molded product 101. Thereafter, as shown in FIG. 18, the rotary blade 130 is rotated to cut away the cut portion 118 of the opening 110 to form the opening 110.
Then, as shown in FIG. 19, the blow molded product 101 is removed from the blow molding die 120 while leaving the cut portion 118 in the blow molding die 120.

However, in this method, since the rotary blade 130 is formed in a cylindrical shape, the molten resin of the parison adheres to the cutting edge 133 of the rotary blade 130 and the rotary blade 130 is rotated, so that the stringing is performed during melting. Occur. Further, when the cutting edge 133 is retracted and positioned from the mold surface of the blow molding die 120 so that the parison and the cutting edge 133 of the rotary blade 130 are separated from each other, the parison enters the gap drawn by the cutting edge 133, and the rotary blade 130. The slide and rotation will be reduced.

Therefore, as shown in FIGS. 20 to 23, there are some that use an elongated opening cutting blade 227. In this case, as shown in FIG. 20, the portion of the blow molding die 220 that forms the tank opening 210 is connected to the blow molding die main body 221 that forms the upper portion of the fuel tank 201. An open cylindrical part forming part 225 for forming the open cylindrical part 211 is provided.
In order to cut out the parison 5 and form the tank opening 210, an opening cutout 217 is provided inside the opening tubular portion 211. The opening excision part 217 is in close contact with the excision part holding part 222 of the blow molding die 220 at the time of blow molding.

A ring-shaped slide space 224 is formed between the cut portion holding portion 222 and the blow molding die body 221. In the slide space 224, an elongated opening cutting blade 227 and a cylindrical opening all-round blade 228 having the same circumference as the circle around which the opening cutting blade 227 rotates can slide on the side surface of the excision holding portion 222. Installed on. A blow pin 223 is slidably attached to the center of the cut portion holding portion 222.

When the parison 5 is sandwiched inside the blow molding die 220, as shown in FIG. 20, the blow pin 223 slides into the parison 5, blows air into the parison 5, and blows.
Then, as shown in FIG. 20, the opening cutting blade 227 is slid in the slide space 224 in the direction in the cavity (downward in FIG. 20).

As shown in FIG. 21, the opening cutting blade 227 has an elongated cutting blade tip 227b and a cutting blade cylinder 227a that slides the cutting blade tip 227b. When the opening cutting blade 227 is slid by the cutting blade cylinder 227 a after the parison 5 is brought into close contact with the opening cylindrical portion forming portion 225, the cutting blade tip 227 b breaks through the parison 5.

Next, as shown in FIG. 21, the opening cutting blade 227 is rotated, and the opening cutting portion 217 closely attached to the cutting portion holding portion 222 of the parison 5 at the cutting blade tip 227b, that is, the opening cylindrical portion molding portion The opening excision 17 that forms the tank opening 210 is cut out from a portion near the tank opening 210 of 225.

At this time, as shown in FIG. 22 and FIG. 24, the cutting gap 229 in which the cutting blade tip 227 b between the opening cylindrical portion forming portion 225 and the cut portion holding portion 222 slides is the opening full peripheral blade 228. Is provided in a slidable manner, and an opening full circumference blade sliding gap 228c is formed in the opening full circumference blade 228 so that the opening cutting blade 227 can slide.

Some of the opening all-around blade sliding gap 228c is provided with a gap opening / closing member 230 so that the parison 5 does not enter. However, as shown in FIGS. 23 and 24, the opening / closing slide pin 231 of the gap opening / closing member 230 slides in the horizontal direction from the inner side of the opening part circumferential blade 228 toward the radially outer side.

The open / close slide pin 231 has an open / close slide pin side surface 231a which is a surface in contact with the opening all-around blade sliding gap 228c, parallel to the slide direction as shown in FIGS. 25 and 26, with respect to the front surface of the open / close slide pin 231. Are formed at right angles.
In addition, the opening all-around blade sliding side 228d, which is the surface that contacts the opening / closing slide pin 231 of the opening all-around blade sliding gap 228c, is also connected to the opening / closing slide pin side 231a in parallel with the sliding direction. It is formed in parallel to.

Therefore, as shown in FIGS. 27 to 30, when the open / close slide pin 231 slides to close the opening full circumference blade sliding gap 228 c, as shown in FIG. 27, the opening full circumference blade sliding gap 228 c is set. When the open / close slide pin 231 is correctly positioned, as shown in FIG. 28, the open / close slide pin 231 is fitted into the opening full circumference blade sliding gap 228c, and the opening full circumference blade sliding side surface 228d. And the opening / closing slide pin side surface 231a can be in contact with each other to close the opening full peripheral blade sliding gap 228c.

However, as shown in FIG. 29, when the opening all-around blade 228 is displaced and the opening / closing slide pin 231 is located in the opening all-around blade sliding gap 228c, as shown in FIG. The end of the open / close slide pin 231 is caught in the corner of the opening full circumference blade sliding gap 228c, and the opening full circumference blade sliding gap 228c cannot be closed.
Therefore, the parison 5 may enter the opening full circumference blade sliding gap 228c at the time of blow molding, and the opening full circumference blade 228 may not operate.

JP 2010-76297 A

  Therefore, the present invention provides a method for forming an opening of a blow-molded product, which can ensure the operation of the entire peripheral blade of the opening, easily cut the opening of the outer wall of the fuel tank or the like, and easily form the opening. It is an issue to provide.

The present invention of claim 1 for solving the above-described problems is a synthetic resin blow-molded product opening forming method for forming an opening of a blow-molded product formed by blow molding in a blow mold.
The opening is extended from the outer wall of the blow molded product, and is formed by bending the outer wall integrally from the outer wall to the outside of the blow molded product. Part
The blow molding die is provided with an opening cylindrical part forming part that forms an opening cylindrical part and a cut part holding part that forms an opening cutting part at a part corresponding to the opening part of the blow molded product, and the opening cylindrical part. A cutting gap is provided between the molded part and the excision holding part, and an opening cutting blade is provided that is slidable in and out of the cavity through the cutting gap to cut the opening.
Cylindrical opening having the same circumference as the inner periphery of the opening that is slidable in and out of the cavity inside the opening that is inserted almost entirely around the opening to be cut. An all-round blade is provided, and the opening all-round blade is slidably provided with a cutting gap.
An opening cutting blade sliding gap is provided on the entire circumference of the opening so that the opening cutting blade can slide, and a gap opening / closing member capable of opening and closing the opening cutting blade sliding gap is provided.
The contact surface of the opening cutting blade sliding gap and the gap opening / closing member is formed as an inclined surface, and the inclined surface of the gap opening / closing member slides and adheres to the inclined surface of the opening cutting blade sliding gap, After closing the opening cutting blade sliding gap with a gap opening and closing member, and closing the cutting gap with the opening all-around blade, a parison is introduced into the blow molding die,
After closely attaching the parison to the opening cylindrical part forming part and the cutting part holding part, the gap part opening / closing member is slid to open the opening part cutting blade sliding gap part, and the opening part from the opening part cutting blade sliding gap part is opened. A blow molding product opening forming method, wherein the cutting blade is slid and the parison of the opening cutting portion is cut off at the cutting blade tip.

In the first aspect of the present invention, the opening portion extends from the outer wall of the blow molded product, and is formed by bending the outer wall integrally from the outer wall to the outside of the blow molded product, and the opening cylindrical portion. It has an opening excision part which is excised and forms an opening. For this reason, the opening cylindrical part and opening cut part of an opening part can be integrally formed from the outer wall of a blow molded product.

The blow molding die is provided with an open cylindrical part forming part for forming an open cylindrical part and a cut part holding part for forming an open cut part at a part corresponding to the opening part of the blow molded product. For this reason, the opening cylindrical part and opening cut part of an opening part can be formed simultaneously by inflating a parison at the time of blow molding, and making it closely_contact | adhere to an opening cylindrical part shaping | molding part and an opening cutting part.

A cutting gap is provided between the opening cylindrical part forming part and the cut-out holding part, and an opening cutting blade is provided that is slidable in and out of the cavity through the cutting gap to cut the opening. For this reason, an opening cut part can be cut | disconnected from an opening cylindrical part with an opening part cutting blade, and an opening part can be formed.

Cylindrical opening having the same circumference as the inner periphery of the opening that is slidable in and out of the cavity inside the opening that is inserted almost entirely around the opening to be cut. An all-round blade was provided, and the opening all-around blade was slidably provided with a cutting gap. For this reason, the parison of the opening excision part cut by the opening cutting blade is not welded again by the entire circumference of the opening, and the parison can be cooled without deforming the shape of the opening. Removal of the excised part is easy.

An opening cutting blade sliding gap portion on which the opening cutting blade can slide is provided on the entire circumference of the opening, and a gap opening / closing member capable of opening and closing the opening cutting blade sliding gap portion is provided. For this reason, an opening part cutting blade slides through the opening part perimeter blade sliding gap of an opening part perimeter blade, and an opening cut part can be excised from an opening cylindrical part.

The contact surface between the opening cutting blade sliding gap and the gap opening / closing member is formed as an inclined surface, and the inclined surface of the gap opening / closing member slides into close contact with the inclined surface of the opening cutting blade sliding gap. The opening cutting blade sliding gap is closed with a gap opening / closing member. For this reason, even if the open / close slide pin slightly deviates from the opening all-around blade sliding gap, the open / close slide pin slides along the inclined surface and fits into the opening all-around blade sliding gap so that can do.

Since the parison is introduced into the blow mold after the cutting gap is closed with the entire circumference of the opening, the parison does not enter from the cutting gap, and the opening cutting blade can be easily cut with the opening cutting blade. Can be excised.

After closely attaching the parison to the opening cylindrical part forming part and the cutting part holding part, the gap part opening / closing member is slid to open the opening part cutting blade sliding gap part, and the opening part from the opening part cutting blade sliding gap part is opened. The cutting blade is slid, and the parison of the excision holding portion is excised at the cutting blade tip. For this reason, since the parison does not protrude into the opening all-around blade sliding gap, the opening cutting blade slides smoothly from the opening all-around blade sliding gap, and the opening excision can be easily cut off. .

According to the second aspect of the present invention, the gap opening / closing member that closes the opening cutting blade sliding gap of the entire circumferential edge of the opening slides radially from the inside toward the outside with respect to the entire circumferential edge of the opening. This is a method for forming an opening of a blow molded product.

According to the second aspect of the present invention, the gap opening / closing member that closes the opening cutting blade sliding gap of the entire circumferential edge of the opening slides radially from the inside toward the outside with respect to the entire circumferential edge of the opening. Therefore, the open / close slide pin can slide along the inclined surface without interfering with the sliding of the entire circumferential edge of the opening, and the open / close slide pin can be brought into close contact with the sliding clearance of the entire circumferential edge of the opening.

According to the third aspect of the present invention, the opening cutting blade is narrow and elongated, is slidable in and out of the cavity, and rotates along the inner peripheral surface of the opening cylindrical portion to This is a method for forming an opening of a blow molded product for excising a parison.

In the third aspect of the present invention, the opening cutting blade is narrow and elongated, is slidable in and out of the cavity, and rotates along the inner peripheral surface of the opening cylindrical portion to Remove the parison. For this reason, the parison closely attached to the opening cylindrical portion molding portion can be easily cut with the elongated opening portion cutting blade, and the parison does not adhere to the opening portion cutting blade.

The contact surface between the opening cutting blade sliding gap and the gap opening / closing member is formed as an inclined surface, and the inclined surface of the gap opening / closing member slides into close contact with the inclined surface of the opening cutting blade sliding gap. In order to close the opening cutting blade sliding gap with the gap opening and closing member, the opening and closing slide pin slides along the inclined surface even if the opening and closing slide pin slightly deviates from the opening all-around blade sliding gap, The opening part perimeter blades can be shifted and fitted into the opening part perimeter blade sliding gap for close contact.

After closely attaching the parison to the opening cylindrical part forming part and the opening excision part, the gap opening / closing member is slid to open the opening cutting blade sliding gap part, and the opening part is cut from the opening cutting blade sliding gap part. Since the parison of the opening cutting part is cut off at the tip of the cutting blade by sliding the blade, the parison does not protrude into the opening all-around blade sliding gap. By sliding smoothly, the opening excision can be easily excised.

It is a perspective view of the fuel tank which has the opening part of the blow molded product which is embodiment of this invention. It is sectional drawing of the opening part of the blow molded product which is embodiment of this invention. It is an expanded sectional view of the part holding the cover body of the opening part of the blow molded product which is embodiment of this invention. It is sectional drawing of the part which forms the opening part of the blow molding die used for embodiment of this invention, an opening part cutting blade retreats from the front end surface of an excision part holding part, and a clearance gap part opening-and-closing member is an opening part. It is sectional drawing of a state before closing a perimeter blade sliding gap and a parison closely_contact | adhering to a cavity. It is sectional drawing of the part which forms the opening part of the blow molding die used for embodiment of this invention, an opening part cutting blade retreats from the front end surface of an excision part holding part, and a clearance gap part opening-and-closing member is an opening part. FIG. 6 is a cross-sectional view showing a state in which the entire peripheral blade sliding gap is closed, the parison is in close contact with the cavity, and the blow pin is inserted into the parison. It is sectional drawing of the part which forms the opening part of the blow molding die used for embodiment of this invention, an opening part cutting blade retreats from the front end surface of an excision part holding part, and a clearance gap part opening-and-closing member is an opening part. It is sectional drawing of the state where the parison of the opening bending part of an opening part was compressed by the slide type | mold after closing the perimeter blade sliding clearance and a parison closely_contact | adhered to a cavity. It is sectional drawing of the part which forms the opening part of the blow molding die used for embodiment of this invention, and the cutting-blade front-end | tip part of an opening part cutting blade is inside a cavity from an opening part perimeter blade sliding clearance gap. It is sectional drawing of the state which approached. It is sectional drawing of the part which forms the opening part of the blow molding die used for embodiment of this invention, and the cutting-blade front-end | tip part of an opening part cutting blade is inside a cavity from an opening part perimeter blade sliding clearance gap. It is sectional drawing of the state which approached and rotated and excised the opening cutting part of the opening part of a parison. It is sectional drawing of the part which forms the opening part of the blow molding metal mold | die used for embodiment of this invention, After an opening part cutting blade cut | disconnects a parison, a slide type | mold retreats and formed the opening part. It is sectional drawing. It is a front view of the state where the tip part of the opening part cutting blade fitted in the opening part perimeter blade sliding gap of the opening part perimeter blade of the blow mold used in the embodiment of the present invention. It is the perspective view seen from diagonally downward which shows the state which attached the gap part opening / closing member of the part which forms the opening part of the blow molding die used for embodiment of this invention inside the opening part perimeter blade. It is a top view of the opening-and-closing slide pin of the crevice part opening-and-closing member used for an embodiment of the invention. It is the perspective view seen from the diagonally forward upper part of the opening-and-closing slide pin of the clearance gap opening-and-closing member used for embodiment of this invention. The open / close slide pin of the gap opening / closing member used in the embodiment of the present invention is a schematic diagram of the opening full circumference blade sliding gap portion showing the state before the opening full circumference blade sliding gap of the opening full circumference blade is closed. It is. The opening / closing slide pin of the gap opening / closing member used in the embodiment of the present invention is a schematic diagram of the opening full-circular blade sliding gap portion showing a state in the middle of closing the opening full-circular blade sliding gap of the opening full-circumferential blade It is. The opening / closing slide pin of the opening / closing member for the gap used in the embodiment of the present invention is a schematic view of the opening full circumference blade sliding gap portion showing the state after closing the opening full circumference blade sliding gap of the opening full circumference blade FIG. It is sectional drawing of the state before excising the opening part of the opening shaping | molding part of the conventional blow molding die. It is sectional drawing of the state which the opening cutting blade which cuts off an opening part pierces a parison, and entered into the cavity in the opening shaping | molding part of the conventional blow molding die. It is sectional drawing of the state after rotating an opening cutting blade and excising an opening part in the opening shaping | molding part of the conventional blow molding die. It is sectional drawing of the state in which the opening cutting blade which cuts off an opening part pierced a parison, and entered into the cavity in the opening shaping | molding part of the other conventional blow molding die. It is sectional drawing of the state after rotating an opening cutting blade and excising an opening part in the opening shaping | molding part of the other conventional blow molding die. It is an expanded sectional view of the gap part for cutting and the part of a gap part opening-and-closing member of other conventional blow molding dies, and is a sectional view in the state where the gap part opening-closing member closed the gap part for cutting. It is an expanded sectional view of the gap part for cutting and the part of the gap part opening and closing member of another conventional blow molding die, and the gap part opening and closing member slides from the gap part for cutting and opens the gap part for cutting. It is sectional drawing. It is the perspective view seen from diagonally downward which shows the state which attached the gap part opening-and-closing member of the part which forms the opening part of the other conventional blow molding die to the inner side of the opening part perimeter blade. It is a top view of the opening / closing slide pin of the other conventional clearance opening / closing member. It is the perspective view seen from the diagonally forward upper part of the opening / closing slide pin of the other conventional clearance opening / closing member. It is a schematic diagram which shows the state before the opening-and-closing slide pin of the other conventional gap part opening-and-closing member block | closes the opening part perimeter blade sliding clearance of an opening part perimeter blade. It is a schematic diagram which shows the state after the opening-and-closing slide pin of the other conventional clearance opening / closing member closed the opening all-around blade sliding clearance of the opening all-around blade. It is a schematic diagram which shows the state in which the opening / closing slide pin of the other conventional gap part opening / closing member was caught in the corner part of the opening part perimeter blade sliding clearance of an opening part perimeter blade. It is an expansion schematic diagram which shows the state which the opening-and-closing slide pin of the other conventional gap part opening-and-closing member was caught in the corner part of the opening part perimeter blade sliding gap of an opening part perimeter blade.

The opening structure of a blow molded product and its forming method according to an embodiment of the present invention will be described with reference to FIGS. First, the opening part of the fuel tank for automobiles will be described with reference to FIGS. 1 to 3, and then the method for forming the opening part of the fuel tank for automobiles will be described.

FIG. 1 is a perspective view of a fuel tank 1 having a tank opening 10 formed in the embodiment of the present invention. 2 to 3 are cross-sectional views of the tank opening 10 according to the embodiment of the present invention.
In the embodiment of the present invention, as shown in FIG. 1, the fuel tank 1 has a tank opening 10 for taking in and out components attached to the inside of the fuel tank 1 such as a fuel pump (not shown). Is formed.

The fuel tank 1 is formed by blow molding, and its outer wall is composed of only one layer, or five layers including an outer layer, an inner layer, an intermediate layer formed between the outer layer and the inner layer, and an adhesive layer thereof. In blow molding, the parison 5 composed of the above-mentioned one layer or five layers is used.
In the case of five layers, the outer layer and the inner layer are formed from a thermoplastic synthetic resin that has high strength and maintains strength against fuel oil, and the intermediate layer is formed from a thermoplastic synthetic resin that has very little permeation of fuel oil. The adhesive layer is made of a thermoplastic synthetic resin that bonds the outer layer and the intermediate layer and the inner layer and the intermediate layer, respectively.

As shown in FIG. 1, the tank opening 10 is formed on the upper surface of the fuel tank 1, and the tank opening 10 is left as the tank opening 10 so that a fuel pump or the like is assembled. There are cases where the body 40 is attached and locked, or the fuel supply pipe 4 and the vent valve 3 are welded to the tank opening 10.

As shown in FIG. 2, the tank opening 10 is formed on the upper surface of the fuel tank 1, and the tank opening 10 is locked with a lid 40 attached thereto.
As shown in FIG. 2, the locking structure of the lid 40 in the tank opening 10 includes a locking ring 14 that is a lid locking member embedded in the tank opening 10 and a lock plate that is an attachment member. 15 is sandwiched.
The lid body 40 is formed in a substantially disk shape, and a flange portion 41 protruding along the inner periphery of the tank opening 10 is formed on the lower surface to prevent the lid body 40 from shifting.

As shown in FIG. 3, the lock plate 15 that holds the lid 40 has a ring shape and a cross-sectional shape formed in a flat plate shape, and an engagement claw portion 15 a is formed. The locking ring 14 embedded in the tank opening 10 is formed with a locking hole 14a at a portion corresponding to the engaging claw 15a. The engaging claw 15a is inserted into the locking hole 14a, and the lid body 40 can be locked.

The tank opening 10 of the fuel tank 1 is formed integrally and continuously from the fuel tank 1 with the same material, as will be described later in the manufacturing method. A locking ring 14 is embedded in the tank opening 10. The locking ring 14 is made of a metal plate and is formed in a bent substantially cylindrical shape.
Without using the locking ring 14, a screw portion can be formed outside the opening cylindrical portion 11 of the tank opening portion 10 and the lid body 40 can be screwed.

The lock plate 15 presses the periphery of the lid 40 that closes the tank opening 10 of the fuel tank 1 against the tank opening 10, and when the lock plate 15 is attached to the locking ring 14, The lid 40 can be brought into close contact with the tank opening 10 and the sealing property can be secured.

As shown in FIG. 3, the tank opening 10 is formed of an opening cylindrical portion 11 and an opening bent portion 12.
The opening cylindrical portion 11 is formed by extending a thermoplastic synthetic resin wall composed of an outer layer, an inner layer, and an intermediate layer constituting the outer wall of the fuel tank 1 outwardly from the fuel tank 1 in a cylindrical shape. . A locking ring 14 that is a lid locking member is embedded in the outer layer of the open cylindrical portion 11. A material constituting the thermoplastic synthetic resin wall of the outer layer enters the fixing hole or notch of the locking ring 14. For this reason, the locking ring 14 can be firmly fixed to the tank opening 10.

The opening bent portion 12 is formed integrally and continuously from the tip of the opening tubular portion 11 of the tank opening 10, and expands the diameter of the opening tubular portion 11, that is, from the tip of the opening tubular portion 11. It bends outward at a right angle, and further bends in the form of a hairpin in the center direction of the tank opening 10 so as to be folded in the vicinity of the center, and a layer of thermoplastic synthetic resin is superimposed on the top and bottom to the opening surface of the tank opening 10 It is formed to have parallel outer surfaces.

For this reason, the opening bent portion 12 is configured by two layers, with the outer layer, the inner layer, and the intermediate layer constituting the wall of the fuel tank 1 overlapping each other in the vertical direction. Accordingly, the tank opening 10 is continuously formed integrally with the same material from the fuel tank 1 and has excellent sealing performance, and the portion other than the opening compression portion 13 described later of the opening bent portion 12 is thick. It is possible to ensure the strength. Further, since the intermediate layer exists, the permeation of fuel can be prevented.

The opening bent portion 12 is formed by compressing in a substantially central portion from a direction perpendicular to the surface of the tank opening 10, and an opening compression portion 13 having a thinner thickness than other portions is formed. The groove portion 18 having a concave cross section is formed over the entire circumference of the tank opening 10. The groove portion 18 of the opening compression portion 13 is fitted with a rubber seal ring 16 having a circular cross section, and when the lid body 40 is attached to the tank opening portion 10, it comes into contact with the back surface of the lid body 40, The gap between the lid 40 and the tank opening 10 can be sealed.
In addition, when forming the opening part of the tank opening part 10, the part from which the parison 5 is excised forms the opening excision part 17. FIG.

Next, based on FIG. 4 to FIG. 16, an example of a method for forming the tank opening 10 of the fuel tank for an automobile, which is a blow-molded product, is an example of a method for forming the opening of the blow-molded product according to the embodiment of the present invention. I will explain to you.
The blow molding die 20 usually sandwiches a synthetic resin parison 5 which is discharged in a molten state from a nozzle of a blow molding machine (not shown) located at the top of the blow molding die 20, with an internal cavity. It is comprised by the blow-molding die main body 21 divided into right and left so that it may shape | mold.

As shown in FIG. 4, the portion of the blow molding die 20 used in the present invention that forms the tank opening 10 is connected to the blow molding die main body 21 on the side forming the upper portion of the fuel tank 1. An open cylindrical portion forming portion 24 for forming ten open cylindrical portions 11 is provided. A cylindrical space that is the same as the inner diameter of the opening tubular portion 11 is provided inside the tank opening 10 of the opening tubular portion forming portion 24 of the blow molding die main body 21, and a columnar slide mold at the center thereof. 25 is fitted.

A ring-shaped slide space 25 b is formed between the slide mold 25 and the blow mold body 21. In the slide space 25b, an elongated opening cutting blade 27 and a cylindrical opening full peripheral blade 28 having the same circumference as the circle around which the opening cutting blade 27 rotates are attached so that the side surface of the slide mold 25 can slide. It has been. A blow pin 23 is slidably attached to the center of the slide mold 25. The bottom part of the slide mold 25 forms a cut-out holding part 22 and holds the opening cut-out part 17 of the parison 5.

The opening cut portion 17 is a portion cut from the parison 5 at an inner portion of the tank opening portion 10 in order to form the tank opening portion 10.
In order to form the open cylindrical part 11 of the tank opening 10, an open cylindrical part forming part 24 is provided at the tip of the blow molding die main body 21. The opening tubular portion forming portion 24 is provided with a locking member holding portion 24 a for holding the locking ring 14.

When the parison 5 is sandwiched inside the blow molding die 20, as shown in FIG. 5, the blow pin 23 slides into the parison 5, and air is blown into the parison 5 to blow. When blow is performed, the parison 5 is in close contact with the cavity surface 26 at the inner surface of the cut portion holding portion 22 of the blow molding die 20, and is in close contact with the opening tubular portion forming portion 24 at the tank opening 10 portion. To do. For this reason, the opening cylindrical part 11 of the tank opening part 10 can be formed in the part of the opening cylindrical part formation part 24. FIG.

At this time, a gap 29 for cutting is provided between the slide tip 25a of the slide mold 25 and the excision holding part 22 so that the opening full peripheral blade 28 and the opening cutting blade 27 can slide. Yes. The cutting gap 29 is slidably provided so that the parison 5 does not enter by the opening full circumference blade 28.

As shown in FIG. 10, the opening full circumference blade 28 is provided with an opening full circumference blade sliding gap 28c so that the opening cutting blade tip 27b of the opening cutting blade 27 can slide. A gap opening / closing member 30 is provided so as to open and close the opening all-around blade sliding gap 28c so that the parison 5 does not enter. As shown in FIG. 14, the opening full circumference blade sliding side surface 28d, which is the open side surface of the opening full circumference blade sliding gap 28c, is formed as an inclined surface so as to abut on an opening / closing slide pin side surface 31a described later. ing.

As shown in FIG. 11, the gap opening / closing member 30 is attached to the inside of the cylindrical opening all-around blade 28. As shown in FIG. 5, the gap opening / closing member 30 includes an opening / closing slide pin 31, an opening / closing slide pin holding portion 32 that slidably holds the opening / closing slide pin 31, and an opening / closing member cylinder 33 that slides the opening / closing slide pin 31. Composed.

As shown in FIG. 14, the opening / closing slide pin 31 is moved by the opening / closing member cylinder 33 of the gap opening / closing member 30 from the inside of the opening full circumference blade 28 toward the outside in the radial direction. It moves to a direction and can close the opening part perimeter blade sliding gap 28c.
As shown in FIGS. 12 and 13, the shape of the open / close slide pin 31 is such that the open / close slide pin side surface 31 a that is in contact with the opening full peripheral blade sliding side surface 28 d of the opening full peripheral blade sliding gap 28 c is Corresponding inclined surfaces are formed so as to come into contact with the opening-side peripheral blade sliding side surface 28d without a gap.

As shown in FIG. 15, the inclined surfaces of the opening full peripheral blade sliding side surface 28 d and the open / close slide pin side surface 31 a are formed to have the same inclination angle. When the open / close slide pin 31 closes the opening full circumference blade sliding gap 28c by the open / close member cylinder 33, even if the open / close slide pin 31 is slightly deviated from the opening full circumference blade sliding gap 28c, the full opening blade slide of the opening portion is provided. The open / close slide pin side surface 31a slides along the inclined surface of the moving side surface 28d, so that the entire circumferential edge 28 of the opening can be displaced as indicated by an arrow in FIG. Therefore, as shown in FIG. 16, the opening / closing slide pin 31 can be brought into close contact with the opening full-circumferential blade sliding gap 28c, and the open part full-circumferential blade sliding gap 28c can be reliably closed.

Next, as shown in FIG. 6, the slide mold 25 is lowered to form the opening bent portion 12 of the tank opening 10 of the parison 5 at the slide mold tip 25a. Thereby, as shown in FIG. 3, the parison 5 can be bent and the opening compression portion 13 can be formed in the opening bending portion 12. Further, the locking ring 14 can be firmly attached to the tank opening 10.

Next, as shown in FIG. 7, the opening / closing slide pin 31 is moved from the opening full circumference blade sliding gap 28c by operating the gap opening / closing member 30.
The opening / closing slide pin 31 is moved by the opening / closing member cylinder 33 of the gap opening / closing member 30. By the movement, the opening / closing slide pin 31 slides and moves in a direction away from the opening full circumference blade sliding gap 28c, so that the opening full circumference blade sliding gap 28c can be opened.

Next, as shown in FIG. 8, the opening cutting blade 27 is slid in the slide space 25b in the direction in the cavity (downward in FIG. 8).
The opening cutting blade 27 has a cutting blade cylinder 27a that slides an elongated opening cutting blade tip 27b. When the opening cutting blade 27 is slid by the cutting blade cylinder 27a after the opening cutting portion 17 of the parison 5 is brought into close contact with the cutting portion holding portion 22, the opening cutting blade passes through the opening all-around blade sliding gap 28c. The tip 27b breaks through the parison 5. At this time, the opening part perimeter blade 28 is opposed to the parison 5 without sliding.

  At the time of blow molding, the opening / closing slide pin 31 closes the opening full circumference blade sliding gap 28c, so that the parison 5 does not enter the opening full circumference blade sliding gap 28c. The opening cutting blade tip 27b smoothly enters the parison 5 through the cutting gap 29, and the opening excision 17 can be easily excised.

At this time, as shown in FIG. 8, the tip of the opening cutting blade tip 27 b is located at a position (downward in FIG. 8) that has broken through the opening cutout 17 of the parison 5 held by the cutout holder 22. ing.
And as shown in FIG. 7, the opening part cutting blade front-end | tip part 27b is located in the cut | interruption of the perimeter blade front-end | tip part 28b.

Next, as shown in FIG. 8, the opening cutting blade 27 is rotated, and the inner portion that forms the tank opening 10 from the parison 5 that is in close contact with the cut-out holding portion 22 at the opening cutting blade tip 27b. The opening excision part 17 is excised. Since the opening cutting part 17 is held by the cutting part holding part 22 of the blow molding die 20, the opening cutting part 17 is hardly deformed, and the opening cutting blade 27 is rotated and the opening cutting part 27 is rotated by the opening cutting blade tip 27 b. Part 17 can be excised. At this time, the opening full circumference blade 28 rotates together with the opening cutting blade 27. Although the entire peripheral blade tip 28b also rotates as the opening cutting blade tip 27b rotates, the tank opening 10 is not deformed because the parison 5 is in contact with the excision holding part 22.

Then, the opening excision part 17 held by the excision part holding part 22 of the parison 5 is cut into a disk shape.
At this time, a part of the opening excision 17 can be left to be a parison connection. In this case, as will be described later, when the fuel tank 1 which is a blow molded product is taken out from the blow molding die 20, the opening cut portion 17 can be taken out from the blow molding die 20 together with the fuel tank 1. it can.

Next, the full circumference blade 28 is slid by the full circumference blade cylinder 28 a, and the full circumference blade tip 28 b is inserted into the cut portion of the parison 5 cut by the opening cutting portion 17. Since the entire peripheral blade tip portion 28b is formed in an all-arc shape other than the narrow opening portion peripheral blade cutting gap 28c, the entire cutting portion of the parison 5 cut by the opening cutting blade tip portion 27b is formed. The entire peripheral blade tip 28b can be inserted around the circumference. For this reason, it can prevent that the cut | disconnected parison 5 fuse | melts again.

Then, the parison 5 is cooled, and as shown in FIG. 9, the opening cutting blade tip portion 27 b and the entire peripheral blade tip portion 28 b are moved backward (upward in FIG. 9) toward the blow molding die 20.
Thereafter, the blow molding die 20 is opened, the fuel tank 1 is taken out from the blow molding die 20, and the opening cut portion 17 of the cut tank opening 10 is taken out from the blow molding die 20 by the extrusion pin 50.

When the parison connecting portion is provided, after the fuel tank 1 is taken out from the blow mold 20, the parison connecting portion is cut and the parison 5 in the tank opening 10 is taken out from the tank body outer wall 2. For this reason, the cut parison 5 does not fall into the fuel tank 1, and the cut parison 5 can be reliably taken out of the fuel tank 1.

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Tank main body outer wall 10 Tank opening part 11 Opening cylindrical part 20 Blow molding die 22 Cutting part holding part 23 Blow pin 25 Slide type 27 Opening cutting blade 28 Opening part perimeter blade 28c Opening part perimeter blade sliding clearance 28d Opening edge all-round blade sliding side 29 Cutting gap 30 Opening / closing member 31 Open / close slide pin 31a Open / close slide pin side

Claims (3)

In the method of forming an opening of a synthetic resin blow-molded product that forms an opening of a blow-molded product formed by blow molding in a blow molding die,
The opening includes an opening cylindrical portion that extends from the outer wall of the blow-molded product and is integrally bent from the outer wall to the outside of the blow-molded product, and an opening cut from the opening cylindrical portion. Having an opening excision to form
The blow molding mold is provided with an opening cylindrical part forming part for forming the opening cylindrical part and a cut part holding part for forming the opening cut part in a part corresponding to the opening part of the blow molded product, A cutting gap is provided between the opening cylindrical portion forming portion and the cut portion holding portion, and an opening cutting blade that is slidable in and out of the cavity through the cutting gap to cut the opening. Provided,
It is slidable in and out of the cavity inside the opening to be inserted in substantially the entire circumference of the opening to be cut, and has the same circumference as the inner periphery of the opening where the opening cutting blade rotates. An opening cutting blade provided with a cylindrical opening all-around blade, the opening all-around blade provided so as to be slidable with the cutting gap, and the opening cutting blade being slidable on the opening all-around blade A sliding gap is provided, and a gap opening / closing member capable of opening and closing the opening cutting blade sliding gap is provided,
The contact surface of the opening cutting blade sliding gap and the gap opening / closing member is formed as an inclined surface, and the inclined surface of the gap opening / closing member slides to the inclined surface of the opening cutting blade sliding gap. The opening cutting blade sliding gap is closed with the gap opening / closing member, and the cutting gap is closed with the opening all-around blade, and then a parison is introduced into the blow mold. ,
After the parison is brought into close contact with the opening tubular portion forming portion and the cut portion holding portion, the gap portion opening / closing member is slid to open the opening portion cutting blade sliding gap portion, and the opening portion cutting blade slide. An opening forming method for a blow-molded product, wherein the opening cutting blade is slid from a moving gap portion, and the parison of the cutting portion holding portion is cut off at the tip of the cutting blade. 2. The gap opening / closing member that closes the opening cutting blade sliding gap of the entire circumference of the opening slides radially from the inside toward the outside with respect to the entire circumference of the opening. A method for forming an opening of a blow-molded product as described in 1. above. The opening cutting blade is narrow and elongated, is slidable in and out of the cavity, and rotates along the inner peripheral surface of the opening cylindrical portion to cut the parison of the opening cutting portion. The method for forming an opening of a blow molded article according to claim 1 or 2.