JP2015193212A - Method for forming opening in blow molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming an opening in a blow molded product, allowing the opening in an outer wall of a fuel tank or the like to be easily cut off without remaining cutting dregs in the opening.SOLUTION: In the method for forming an opening in a blow molded product, the opening 10 includes a cylindrical opening part 11 and a cut-off opening part 12. A blow forming mold 20 includes a cylindrical opening part forming part 24, a cut off part holding part 22 and a blow pin 23. After a parison 5 is closely contacted with the blow forming mold 20, the blow pin 23 is slid such that the air is blown into a cavity for cooling of the parison 5. After the parison 5 is cooled, a cutting blade 27 to make the opening is slid through a gap 29 for cutting, so that the cutting blade tip 27b is rotated by a specified angle. Within one rotation, the cutting blade tip 27b cuts off the parison 5 of a cut off opening part 17.

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, extruded from a die of a blow molding machine, the parison is sandwiched between molds, and air is blown into the parison to form a hollow body such as an automobile fuel tank. 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. 27, the opening 110 is formed by providing a slidable rotary blade 130 on a 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. 27 to 29, the opening 110 is formed by forming a cutting edge 133 at the tip of the rotary blade 130, slightly protruding the blade 133 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. 28, 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. 29, 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, when the cut portion 118 of the opening 110 is cut, the surface of the resin parison is cut little by little while the rotary blade 130 rotates. The remaining may fall into the hollow body.
In addition, there was a problem that chips were generated on the cut surface and could not be cut cleanly.

JP 2010-76297 A

  Therefore, an object of the present invention is to provide a method for forming an opening of a blow molded product that facilitates cutting of an opening of an outer wall of a fuel tank or the like and does not leave a notch in the opening.

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 molding part and the excision holding part, and an opening cutting blade that can slide inside and outside the cavity through the cutting gap is provided, and the excision holding part can be slid into and out of the cavity. Provided a blow pin,
After closely attaching the parison to the opening cylindrical part molding part and the opening excision part, after sliding the blow pin and penetrating the parison, air is blown from the blow pin into the cavity, the parison is cooled,
After the parison is cooled, the opening cutting blade is slid from the cutting gap, the cutting blade tip is rotated to a predetermined angle, and the parison at the opening cutting portion is cut off by the cutting blade tip. It is a method for forming an opening of a molded product

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 was provided between the opening cylindrical portion forming portion and the cut portion holding portion, and an opening cutting blade that was slidable in and out of the cavity through the cutting gap was provided. For this reason, an opening part cutting blade can be slid from the clearance gap part for cutting, and an opening cutting part can be cut out from an opening cylindrical part.
Since the blow pin slidable in and out of the cavity is provided in the excision holding part, the blow pin can break through the parison, and air can be blown into the parison, so that the parison can be brought into close contact with the blow mold.

After the parison is brought into close contact with the opening cylindrical portion forming portion and the opening excision portion, the blow pin is slid to penetrate the parison, and then air is blown from the blow pin into the cavity to cool the parison. For this reason, the parison is brought into close contact with the cavity by the air blown from the blow pin, the parison can be cooled in a short time, and the parison can be set to a predetermined hardness.

After cooling the parison, the opening cutting blade is slid from the cutting gap, the tip of the cutting blade is rotated at a predetermined angle, and the parison at the opening excision is cut off at the tip of the cutting blade. For this reason, after the parison is cooled to a predetermined hardness, it is cut out once with a sharp opening cutting blade, so that no cuts are generated in the opening and the time of the cutting process can be shortened.

In the present invention of claim 2, the predetermined angle for sliding the opening cutting blade from the cutting gap and rotating the cutting blade tip after cooling the parison is about When there are a plurality of opening cutting blades at 360 degrees, this is a blow molded product opening forming method in which the total of the plurality of rotation angles is about 360 degrees.

In the present invention of claim 2, after cooling the reson, the predetermined angle at which the opening cutting blade is slid from the cutting gap and the tip of the cutting blade is rotated is about When there are a plurality of opening cutting blades, the total of the plurality of rotation angles is about 360 degrees. Therefore, when there is one opening cutting blade, the opening is cut by one rotation, and when there are a plurality of opening cutting blades, each opening cutting blade rotates once by a predetermined angle. By doing so, the entire opening can be reliably cut, the cutting process time can be shortened, and cutting waste can be eliminated.

The present invention of claim 3 is the method of forming an opening of a blow molded product, wherein the time for sending air from the blow pin into the cavity is 30 to 60 seconds.

In this invention of Claim 3, since the time which sends air in a cavity from a blow pin is 30 to 60 second, the parison in a cavity can be cooled to predetermined | prescribed hardness, The parison at the opening excision can be cut reliably with one rotation.

According to the present invention of claim 4, the opening cutting blade is formed to be narrow and narrow, slidable in and out of the cavity, and rotated along the inner peripheral surface of the opening tubular portion to open the opening cutting portion. This is a method for forming an opening of a blow molded product for excising the parison.

According to the present invention of claim 4, the opening cutting blade is formed to be narrow and narrow, slidable in and out of the cavity, and rotated along the inner peripheral surface of the opening cylindrical portion to Remove the parison. For this reason, the parison that is in close contact with the opening cylindrical portion forming portion can be easily cut with the elongated opening portion cutting blade.

The present invention of claim 5 is provided with a gap opening / closing member capable of opening and closing the cutting gap, and after closing the cutting gap with the gap opening / closing member, the parison is introduced into the blow mold, After closely contacting the opening cylindrical part forming part and the opening excision part, the gap opening / closing member is slid to open the cutting gap part, and the opening cutting blade is slid from the cutting gap part. This is a method for forming an opening of a blow-molded product in which the parison of the opening excision is excised.

In this invention of Claim 5, since the clearance part opening-closing member which can open and close the clearance gap part for cutting was provided, when closely attaching a parison to a blow molding die, it prevents that a parison enters from the clearance gap part for cutting. The sliding of the opening cutting blade can be facilitated.
After closing the cutting gap with the gap opening / closing member, the parison introduced into the blow mold is blown to bring the parison into close contact with the blow mold. Sometimes, the parison does not enter the cutting gap.

  After closely attaching the parison to the opening cylindrical part forming part and the opening excision part, sliding the gap opening / closing member to open the cutting gap part, sliding the opening cutting blade from the cutting gap part, the cutting blade tip Cut out the parison at the opening. For this reason, since the parison of the part for the clearance gap part does not protrude, the opening part cutting blade can slide smoothly from the clearance part for cutting, and the parison of the opening excision part can be easily excised.

The present invention of claim 6 is provided with a gap opening and closing member capable of opening and closing the cutting gap, and after closing the cutting gap with the gap opening and closing member, the parison is formed into the opening cylindrical portion forming portion and the opening cutting portion. After close contact, the opening cutting blade is inserted into the cutting gap, and the parison is formed with a recess at the tip of the opening cutting blade, then the blow pin is slid through the parison, and then air is blown from the blow pin. Air blows into the tee, cools the parison,
After cooling the parison, slide the opening cutting blade from the gap for cutting, pierce the tip of the opening cutting blade into the concave portion of the parison, and blow out the parison at the opening excision with the tip of the opening cutting blade It is a method for forming an opening of a molded product.

In this invention of Claim 6, after forming a recessed part with the front-end | tip of an opening part cutting blade in a parison, after sliding a blow pin and penetrating a parison, air is blown into a cavity from a blow pin, and a parison is cooled. After the parison is cooled, the opening cutting blade is slid from the gap for cutting, the tip of the opening cutting blade is pierced into the concave portion of the parison, and the parison of the opening excision is cut by the tip of the opening cutting blade.

For this reason, a recess can be formed in the parison at the tip of the opening cutting blade, and the recess can be formed thin. Accordingly, the thickness of the portion to be cut off at the tip of the opening cutting blade can be reduced, the resin temperature can be lowered, the cutting can be easily performed, the cutting surface can be cut out in a clean state, and cutting scraps etc. Occurrence can be prevented.

The present invention of claim 7 is provided with a gap opening and closing member capable of opening and closing the cutting gap, and after closing the cutting gap with the gap opening and closing member, the parison is formed into the opening cylindrical portion forming portion and the opening cutting portion. After close contact, the opening cutting blade is inserted into the cutting gap, and the parison is formed with a recess at the tip of the opening cutting blade, then the blow pin is slid through the parison, and then air is blown from the blow pin. Air blows into the tee, cools the parison,
After cooling the parison, retract the opening cutting blade once from the cutting gap, then slide the opening cutting blade from the cutting gap and pierce the opening of the opening cutting blade into the recess of the parison. It is a method for forming an opening of a blow molded product in which the parison of the opening excision is cut with the tip of the cutting blade.

In this invention of Claim 7, after forming a recessed part with the front-end | tip of an opening part cutting blade, a blow pin is slid, and after passing through a parison, air is blown into a cavity from a blow pin, and a parison is cooled. After the parison is cooled, the opening cutting blade is once retracted from the cutting gap, then the opening cutting blade is slid from the cutting gap, and the tip of the opening cutting blade is pierced into the recess of the parison. Cut off the parison at the opening cut with the tip of the cutting blade.

For this reason, by making the opening cutting blade move backward once and move forward, the piercing force of the opening cutting blade into the concave portion of the parison can be increased, cutting is easy, and the cutting surface is cut clean. It is possible to prevent the generation of excision waste.

The present invention of claim 8 is provided with a cutting gap between the opening cylindrical part molding part and the cut part holding part, and provided with an opening cutting blade that can slide through the cutting gap part into and out of the cavity, Insert the opening cutting blade into the cutting gap, close the cutting gap with the opening cutting blade, introduce the parison into the blow molding die, and use the parison as the opening cylindrical part forming part and the opening cutting blade After closely forming a recess in the parison at the tip of the opening cutting blade, sliding the blow pin through the parison, blowing air from the blow pin into the cavity, cooling the parison,
After the parison is cooled, the opening cutting blade is retracted once from the concave portion of the parison, then the tip of the opening cutting blade is stabbed into the concave portion of the parison, and the blow that cuts off the parison of the opening excision portion with the tip of the opening cutting blade It is a method for forming an opening of a molded product.

In the present invention of claim 8, after closing the gap for cutting with the opening cutting blade, introducing the parison into the blow molding die, and attaching the parison to the opening cylindrical portion molding portion and the opening cutting blade, After sliding the blow pin through the parison, air is blown from the blow pin into the cavity, the parison is cooled, and after the parison is cooled, the opening cutting blade is once retracted from the recess of the parison, and then the opening The tip of the cutting blade is pierced into the concave portion of the parison, and the parison at the opening excision is cut with the tip of the opening cutting blade.

For this reason, the gap opening / closing member can be abolished, the defect in forming the opening due to the malfunction of the gap opening / closing member can be reduced, and the structure of the blow molding die can be simplified. Blow mold and its maintenance cost are reduced. In addition, by making the opening cutting blade move backward and move forward, the piercing force of the opening cutting blade can be increased, the resection is easy, the cut surface can be removed in a clean state, and the resection is performed. Generation of scraps can be prevented.

The present invention of claim 9 is provided with a cutting gap between the opening cylindrical part forming part and the cut-out holding part, and provided with an opening cutting blade that can slide through the cutting gap into and out of the cavity, The gap opening / closing member was inserted into the cutting gap, the cutting gap was closed with the gap opening / closing member, and the parison was recessed at the tip of the gap opening / closing member, and then the blow pin was slid through the parison. Later, air is blown from the blow pin into the cavity to cool the parison,
This is an opening forming method for a blow-molded product in which the opening / closing member for the gap is retracted, the tip of the opening cutting blade is pierced into the concave portion of the parison, and the parison of the opening cutting portion is cut with the tip of the opening cutting blade.

In the present invention of claim 9, the gap opening / closing member is inserted into the cutting gap, the cutting gap is closed with the gap opening / closing member, and the parison is recessed at the tip of the gap opening / closing member. After sliding through the parison, air is blown from the blow pin into the cavity, the parison is cooled, the tip of the opening cutting blade is pierced into the recess of the parison, and the opening excision is made at the tip of the opening cutting blade Excise the parison.

For this reason, at the front-end | tip of the opening-and-closing member for clearance gaps, while entering the clearance gap for cutting | disconnection of a parison, the recessed part of a parison can be formed reliably, and the recessed part of a parison can be cut | disconnected with an opening part cutting blade. Moreover, it can prevent that a parison adheres to the front-end | tip of an opening part cutting blade.

According to a tenth aspect of the present invention, in the blow molding die, a recess is provided on the surface of the cavity adjacent to the gap for cutting, and the parison is formed in the recess on the surface of the cavity when the parison is brought into close contact with the surface of the cavity. After thinning the parison closely attached to the opening excision part, sliding the blow pin, penetrating the parison, blowing air from the blow pin into the cavity, cooling the parison,
This is a blow molded product opening forming method in which the tip of the opening cutting blade is stabbed into a thin part of the parison and the parison of the opening cutting portion is cut with the tip of the opening cutting blade.

According to the present invention of claim 10, the blow molding die is provided with a recess on the surface of the cavity adjacent to the gap for cutting, and the parison is formed in the recess on the surface of the cavity when the parison is brought into close contact with the surface of the cavity. After making the parison in close contact with the opening excision part thin, slide the blow pin, penetrate the parison, blow air from the blow pin into the cavity, cool the parison, and open the cutting blade Is inserted into the thin part of the parison, and the parison at the opening excision part is excised with the tip of the opening cutting blade. For this reason, the parison can enter the concave portion of the cavity surface of the blow molding die to make the parison in close contact with the opening excision part thin, and the resin temperature of the part to be excised with the tip of the opening cutting blade can be reduced. The cutting surface can be lowered, the excision is easy, the cut surface can be excised in a clean state, and the generation of excision debris and the like can be prevented.

The present invention of claim 11 is the method of forming an opening of a blow molded product in which the tip of the opening cutting blade is formed in an acute angle.

In the present invention of claim 11, since the tip of the opening cutting blade is formed in an acute angle shape, excision is easy, the cut surface can be excised in a clean state, and generation of excision debris and the like can be prevented. .

In the present invention, after the parison is brought into close contact with the opening cylindrical portion forming portion and the opening excision portion, air is blown from the blow pin into the cavity, and the parison is cooled by the air blown from the blow pin. While closely contacting the tee, the parison can be cooled in a short time so that the parison has a predetermined hardness.

After the parison is cooled, the opening cutting blade is slid from the cutting gap, the cutting blade tip is rotated to a predetermined angle, and the parison of the opening cutting portion is cut at the cutting blade tip by one rotation or less. Since the parison is cooled to a predetermined hardness for excision, it is cut out once with a sharp opening cutting blade so that no cuts are generated in the opening.

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 the 1st Embodiment of this invention. It is sectional drawing of the part which forms the opening part of the blow molding die used for the 1st Embodiment of this invention, an opening part cutting blade and a blow pin retreat rather than the front end surface of a cutting part holding part, and a parison is It is sectional drawing of the state before 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 the 1st Embodiment of this invention, a clearance gap opening-and-closing member closes the clearance gap for cutting, and an opening part cutting blade hold | maintains a cutting part It is sectional drawing of the state which retreated rather than the front end surface of a part, a parison closely_contact | adhered to a cavity, and the blow pin was inserted in a parison. It is sectional drawing of the part which forms the opening part of the blow molding die used for the 1st Embodiment of this invention, and an opening part cutting blade retreats rather than the front end surface of an excision part holding | maintenance part, and a clearance part opening-closing member FIG. 6 is a cross-sectional view of a state where the parison of the opening bent portion of the opening is compressed by the slide mold after closing the gap for cutting and blowing air from the blow pin, and the parison adheres to the cavity. It is sectional drawing of the part which forms the opening part of the blow molding die used for the 1st Embodiment of this invention, and a clearance gap opening-and-closing member has a clearance gap part opened, and the cutting blade of an opening part cutting blade It is sectional drawing of the state which the front-end | tip part entered the inside of the cavity from the clearance gap part for cutting It is sectional drawing of the part which forms the opening part of the blow molding die used for the 1st Embodiment of this invention, and the cutting-blade front-end | tip part of an opening part cutting blade enters the inside of a cavity from the clearance gap part for a cutting | disconnection FIG. 5 is a cross-sectional view showing a state in which the opening cut portion of the opening portion of the parison is cut and rotated. It is sectional drawing of the part which forms the opening part of the blow molding die used for the 1st Embodiment of this invention, and the opening part cutting blade, the opening part gap prevention member, and the blow pin cut out the opening part cutting part of a parison FIG. 8 is a cross-sectional view showing a state in which the distal end surface of the excision holding part is retracted. It is an expanded sectional view of the gap part for cutting of a blow molding die used for a 1st embodiment of the present invention, and the portion of an opening cutting blade, and a sectional view of a state before an opening cutting blade cuts a parison It is. It is an expanded sectional view of the gap part for cutting of the blow mold used for a 1st embodiment of the present invention, and the portion of an opening cutting blade, and is a sectional view in the state where an opening cutting blade cut a parison. . It is a bottom view which shows the rotation state of the clearance gap for cutting of the blow molding die used for the 1st Embodiment of this invention, and an opening part cutting blade, and one opening part cutting blade is provided in the clearance gap for cutting. FIG. It is a bottom view which shows the rotation state of the clearance gap for cutting of the blow molding die used for the 1st Embodiment of this invention, and an opening part cutting blade, and two opening part cutting blades are provided in the clearance gap for cutting. FIG. It is a bottom view which shows the rotation state of the clearance gap for cutting of the blow molding die used for the 1st Embodiment of this invention, and an opening part cutting blade, and three opening part cutting blades are provided in the clearance gap part for cutting. FIG. It is a bottom view which shows the rotation state of the clearance gap for cutting of the blow molding die used for the 1st Embodiment of this invention, and an opening part cutting blade, and four opening part cutting blades are provided in the clearance gap part for cutting. FIG. FIG. 5 is an enlarged cross-sectional view of a cutting gap portion and an opening cutting blade portion of a blow molding die used in the second embodiment of the present invention, and a cross-sectional view in a state where the opening cutting blade forms a recess in the parison. It is. FIG. 6 is an enlarged cross-sectional view of a cutting gap portion and an opening cutting blade portion of a blow molding die used in the second embodiment of the present invention, and a cross-sectional view in a state in which the opening cutting blade is retracted from a recess of a parison It is. It is an expanded sectional view of the gap part for cutting of the blow molding die used for the 2nd embodiment of the present invention, and the part of an opening part cutting blade, and the tip of a gap part opening-and-closing member protrudes in the cavity It is sectional drawing. In the 2nd Embodiment of this invention, it is sectional drawing of the state which provided the recessed part and the long expansion | deployment part in the vicinity of the opening excision part. It is an expanded sectional view of the gap part for cutting of a blow molding die used for a 3rd embodiment of the present invention, and the part of an opening part cutting blade, and the tip of an opening part cutting blade has formed the crevice of a parison. It is sectional drawing. It is sectional drawing of the part which forms the opening part of the blow molding die used for the 3rd Embodiment of this invention, and is sectional drawing of the state which the opening part cutting blade retreated from the recessed part of the parison. It is an expanded sectional view of the gap part for cutting of a blow mold used for a 3rd embodiment of the present invention, and the portion of an opening part cutting blade, and sectional drawing in the state where the opening part cutting blade pierced the crevice of a parison It is. It is an expanded sectional view of the gap part for cutting of a blow molding die used for a 3rd embodiment of the present invention, and the portion of an opening part cutting blade, and sectional drawing in the state where the opening part cutting blade formed the crevice in a parison It is. FIG. 6 is an enlarged cross-sectional view of a cutting gap portion and an opening cutting blade portion of a blow molding die used in the third embodiment of the present invention, and a cross-sectional view in a state where the opening cutting blade is retracted from a recess of a parison It is. It is an expanded sectional view of the gap part for cutting of a blow mold used for a 3rd embodiment of the present invention, and the portion of an opening part cutting blade, and sectional drawing in the state where the opening part cutting blade pierced the crevice of a parison It is. It is sectional drawing of the front-end | tip of the opening part cutting blade used for embodiment of this invention. It is an expanded sectional view of the gap part for cutting of a conventional blow molding die, and the part of a gap part opening-and-closing member, and a sectional view in the state where the gap part opening-and-closing member closed the gap part for cutting. It is an expanded sectional view of the gap part for cutting and the part of a gap part opening and closing member of the conventional blow molding die, and the sectional view of the state where the gap part opening and closing member slides from the gap part for cutting and opens the gap part for cutting It is. It is sectional drawing of the state after excising the opening part of the opening shaping | molding part of the conventional blow molding die.

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.

The lock plate 15 that sandwiches the lid 40 has a ring shape and a cross-sectional shape formed in a flat plate shape, and an engagement claw portion 15a 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. 15, a method for forming an opening of a blow molded product according to the first embodiment of the present invention will be described. The method will be described as an example.
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 slide mold tip 25 a is provided at the tip of the slide mold 25 to form the opening compression part 13. 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 gap stopper 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 through the blow pin air hole 23a. I do. When blow is performed, as shown in FIG. 10, the parison 5 has an inner surface of the cut portion holding portion 22 of the blow molding die 20 in close contact with the cavity surface 26, and an opening cylinder is formed at the tank opening 10 portion. Adheres closely to the shape forming part 24. 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, as shown in FIG. 10, the cutting blade tip 27 b of the opening cutting blade 27 at the tip of the opening cutting blade 27 is located inside the excision holding part 22.

Furthermore, when air is continuously blown from the blow pin air hole 23a, the parison 5 that is in close contact with the cavity surface 26 can be cooled. The time for blowing air from the blow pin air hole 23a into the cavity is preferably 30 to 60 seconds. In this case, the parison 5 initially placed on the blow mold 20 was about 200 ° C., but the parison 5 can be cooled to about 60-100 ° C.

For this reason, the predetermined hardness required for the parison 5 to cut can be obtained. If the air blowing time is less than 30 seconds, the parison 5 is too soft, and the parison may stick to the opening cutting blade 27 when cut by the opening cutting blade 27 described later, and the air blowing time exceeds 60 seconds. In this case, the parison 5 becomes too hard, and the cutting by the opening cutting blade 27 is not smooth, and the parison 5 of the opening cutting portion 17 can be reliably cut by one rotation of the opening cutting blade 27. it can.

At this time, as shown in FIGS. 5 and 11, an opening cutting blade 27 is slidable between the slide mold tip 25 a of the slide mold 25 and the cut-out holding section 22, and a cutting gap 29 is formed. Is provided. A gap opening / closing member 30 is provided to open and close the cutting gap 29 so that the parison 5 does not enter.

The gap opening / closing member 30 is attached to the slide space 25b on the surface opposite to the surface with which the parison 5 of the cut portion holding portion 22 abuts. 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.

When the opening / closing slide pin 31 is slid by the opening / closing member cylinder 34 of the gap opening / closing member 30, the opening / closing slide pin 31 slides in an oblique direction, moves in the direction of the cutting gap 29, and closes the cutting gap 29. Can do. At this time, the other part of the cutting gap 29 that is closed by the opening / closing slide pin 31 is closed by the opening gap stopper 28.

Since the tip of the open / close slide pin 31 is formed in a flat slope shape, it can reach the lower surface of the cutting gap 29. Accordingly, the lower surface of the excision holding portion 22 with which the parison 5 abuts and the lower surface of the distal end of the open / close slide pin 31 can form a flat surface without unevenness, so that the parison 5 enters the cutting gap 29. The surface of the parison 5 of the cutting gap 29 can be a flat surface.

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 cutting gap 29 by operating the gap opening / closing member 30.
In the movement, the opening / closing slide pin 31 is slid by the opening / closing member cylinder 33 of the gap opening / closing member 30. By the sliding, the opening / closing slide pin 31 is guided by the opening / closing slide pin holding portion 32 and slides in an oblique direction, and moves in a direction away from the cutting gap 29 to open the cutting gap 29.

Next, the opening cutting blade 27 is slid in the direction of the cavity (downward in FIG. 7) in the slide space 25b.
The opening cutting blade 27 has an elongated cutting blade tip 27b and a cutting blade cylinder 27a that slides the cutting blade tip 27b. As shown in FIG. 11, when the opening cutting blade 27 is slid by the cutting blade cylinder 27 a after the opening cutting portion 17 of the parison 5 is brought into close contact with the cutting portion holding portion 22, the cutting is performed through the cutting gap 29. The blade tip 27b breaks through the parison 5.

The opening / closing slide pin 31 closes the cutting gap 29 during blow molding so that the parison 5 does not enter the cutting gap 29, and the parison 5 of the cutting gap 29 has a flat surface. The cutting blade tip 27b smoothly enters the parison 5 from the clearance 29 and the opening excision 17 can be easily excised.
At this time, the tip of the cutting blade tip 27b is located at a position (lower side in FIG. 7) that has broken through the opening cutout 17 of the parison 5 held by the cutout holding portion 22.

Next, as shown by the arrow in FIG. 8, the opening portion cutting blade 27 is rotated, and the inner portion that forms the tank opening portion 10 from the parison 5 that is in close contact with the cut portion holding portion 22 at the cutting blade tip portion 27 b. 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 part 17 is rotated by the cutting blade tip part 27 b by the rotation of the opening cutting blade 27. Can be excised. At this time, the opening clearance gap member 28 rotates together with the opening cutting blade 27.

At this time, when there is one opening cutting blade 27. As shown in FIG. 12, it rotates 360 degrees which is one rotation. As described above, since the parison 5 has a predetermined hardness, the opening cutting blade 27 that is a sharp blade can cut the opening cutting portion 17 in one rotation. For this reason, cutting does not occur in the tank opening 10, and it does not take time to clean the tank opening 10 after cutting.

In addition, when there are two opening cutting blades 27. As shown in FIG. 13, each rotation is 180 degrees and the entire rotation is 360 degrees.
When there are three opening cutting blades 27. As shown in FIG. 14, each rotation is 120 degrees, and the entire rotation is 360 degrees.
When there are four opening cutting blades 27. As shown in FIG. 15, each rotation is 90 degrees, and the entire rotation is 360 degrees.
In these cases, the cutting angle can be shortened by reducing the rotation angle of the opening cutting blade 27.

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.

Then, the parison 5 is further cooled, and as shown in FIG. 9, the blow pin 23 is retracted from the parison 5 and the cutting blade tip portion 27b is retracted toward the blow molding die 20 (upward in FIG. 9).
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 with an extrusion pin.

Next, based on FIGS. 16 to 19, the method for forming the opening of the blow molded product according to the second embodiment of the present invention will be described. The method will be described as an example.
The second embodiment is different in that the opening cutting blade 27 forms a recess 5a in a portion where the opening cutting portion 17 of the parison 5 is cut, and the opening cutting blade 27 pierces the recess 5a of the parison 5. Since these parts are the same, different parts will be described, and description of similar parts will be omitted.

Similarly to the first embodiment, when the opening / closing slide pin 31 is slid by the opening / closing member cylinder 34 of the gap opening / closing member 30, the opening / closing slide pin 31 slides in an oblique direction and moves toward the cutting gap 29. Thus, the cutting gap 29 can be closed. At this time, the other part of the cutting gap 29 that is closed by the opening / closing slide pin 31 is closed by the opening gap stopper 28.

Next, the slide mold 25 is lowered, and the opening bent portion 12 of the tank opening 10 of the parison 5 is formed by the slide mold tip 25a. Thereby, as shown in FIG. 16, 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.

Further, at the same time as forming the opening bent portion 12, as shown in FIG. 16, the gap opening / closing member 30 is operated to move the opening / closing slide pin 31 from the cutting gap 29, and the tip of the opening cutting blade 27. Enters the parison 5, and the tip of the opening cutting blade 27 forms the concave portion 5 a of the parison 5 in the parison 5 where the opening cut portion 17 of the parison 5 is cut.

In the second embodiment, after forming the recess 5a at the tip of the opening cutting blade 27 in the parison 5, the blow pin 23 is slid to penetrate the parison 5, and then air is blown from the blow pin 23 to the blow molding die 60. Then, the parison 5 is cooled. Since the recess 5 a of the parison 5 is formed thinner than the other parts of the parison 5, the resin temperature can be lowered during cooling by the blow pin 23.

After the parison 5 is cooled, the opening cutting blade 27 is slid from the cutting gap 29, and the parison 5 of the opening cutting portion 17 is cut off at the tip of the opening cutting blade 27.
The concave portion 5a to be cut off at the tip of the opening cutting blade 27 is formed with a thin wall, can lower the resin temperature, can be cut easily, can cut off the cut surface in a clean state, and generate cutting waste and the like. Can be prevented.

At this time, as shown in FIG. 17, after cooling the parison 5, the opening cutting blade 27 is once retracted from the recess 5a of the parison 5, and then the opening cutting blade 27 is stabbed into the parison 5 to cut out the recess. Can do.
In this case, it is possible to increase the piercing force of the opening cutting blade 27 by moving the opening cutting blade 27 backward once and advance it, and it is easy to cut and cut the cut surface in a clean state. And the generation of excision waste can be prevented.

Further, as shown in FIG. 18, the recess 5 a of the parison 5 can be provided at the tip of the opening / closing slide pin 31 of the gap opening / closing member 30.
When the opening / closing slide pin 31 of the gap opening / closing member 30 slides, the opening / closing slide pin 31 slides in an oblique direction, moves in the direction of the cutting gap 29, and can close the cutting gap 29. At this time, the tip of the open / close slide pin 31 of the cutting gap 29 protrudes into the cavity of the blow molding die 20.

Thereafter, when the parison 5 is brought into close contact with the cavity of the blow mold 20, the recess 5 a can be formed in a portion where the tip of the open / close slide pin 31 contacts the cutting gap 29 of the parison 5.
Further, the blow pin is slid to penetrate the parison, and then air is blown from the blow pin into the cavity to cool the parison 5. After the parison 5 is cooled, the gap opening / closing member 30 is retracted from the cutting gap 29.

Thereafter, the opening cutting blade 27 is slid from the cutting gap 29, and the recess 5 a of the parison 5 of the opening cutting portion 17 is cut off at the tip of the opening cutting blade 27.
The concave portion 5a to be cut off at the tip of the opening cutting blade 27 is formed with a thin wall, can lower the resin temperature, can be cut easily, can cut off the cut surface in a clean state, and generate cutting waste and the like. Can be prevented.

Moreover, as shown in FIG. 19, the recessed part 5b of the parison 5 can be provided in the vicinity of the cutting part of the opening cutting part 17, and the cutting part of the opening cutting part 17 can be formed thinly. The recess 5b of the parison 5 can be formed by providing a recess 26a on the cavity surface 26 provided in the vicinity of the cutting gap 29 of the blow molding die 20, as shown in FIG.
At this time, as shown in FIG. 19, the opening excision part 17 of the parison 5 is formed by lengthening a part of the opening excision part 17 held by the excision part holding part 22 of the blow molding die 20, thereby opening the excision part. The 17 cut portions can be formed even thinner.

Next, based on FIGS. 20 to 28, the method for forming the opening of the blow molded product according to the third embodiment of the present invention will be described. The method will be described as an example.
In the third embodiment, as in the second embodiment, the opening cutting blade 27 forms a recess 5a in a portion where the opening cutting portion 17 of the parison 5 is cut, and the recess 5a of the parison 5 is opened. Since the cutting blade 27 is pierced and the other parts are the same, the different parts will be described and the description of the similar parts will be omitted.

The third embodiment is different from the second embodiment in that the gap opening / closing member 30 is not used, and the opening cutting blade 27 is used instead of the gap opening / closing member 30 for cutting. 29 is closed, and the other parts are the same. Therefore, different parts will be described, and description of similar parts will be omitted.

As shown in FIG. 20, the opening cutting blade 27 can be slid and inserted into the cutting gap 29 between the slide mold 25 and the cut-out holding section 22 to close the cutting gap 29. At this time, the other part of the cutting gap 29 covered by the opening cutting blade 27 is closed by the opening gap stopper 28.
Further, at the same time when the opening bent portion 12 is formed, as shown in FIG. 20 and FIG. 23, the opening cutting portion 27 of the opening cutting blade 27 is formed at the portion that cuts the opening cutting portion 17 of the parison 5. A recess 5a of the parison 5 is formed.

In the third embodiment, after forming the recess 5a at the tip of the opening cutting blade 27 in the parison 5, the blow pin 23 is slid to penetrate the parison 5, and then air is blown from the blow pin 23 to the blow molding die 60. Then, the parison 5 is cooled. Since the recess 5 a of the parison 5 is formed thinner than the other parts of the parison 5, the resin temperature can be lowered during cooling by the blow pin 23.

Next, as shown in FIGS. 21 and 24, after the parison 5 is cooled, the opening cutting blade 27 is retracted from the recess 5a of the parison 5 and the cutting gap 29, as shown in FIG. Then, the opening cutting blade 27 is slid, and the concave portion 5 a of the parison 5 of the opening cutting portion 17 is cut off at the tip of the opening cutting blade 27.
The concave portion 5a to be cut off at the tip of the opening cutting blade 27 is formed with a thin wall, can lower the resin temperature, can be cut easily, can cut off the cut surface in a clean state, and generate cutting waste and the like. Can be prevented.

In the first to third embodiments, the cutting blade tip 27b of the opening cutting blade 27 can take various shapes with a sharpened tip, as shown in FIG.
For example, in the case of FIG. 26 (a), the cutting blade tip 27b of the opening cutting blade 27 forms a pointed portion on one side of the tip, and in the case of FIG. 26 (b), the opening The cutting blade tip 27b of the cutting blade 27 is formed to be inclined sharply. In the case of FIG. 26 (c), the cutting blade tip 27b of the opening cutting blade 27 is on one side of the tip. A sharp portion is formed, and the sharp portion is formed longer than the case of FIG. 26A. In the case of FIG. 26A, the cutting blade tip portion 27b of the opening cutting blade 27 is A pointed portion is formed on one side of the tip, and a curved surface is formed from the pointed portion.

In any shape, depending on the thickness of the parison 5, the size of the concave portion 5a formed in the parison 5, the material of the parison 5, the required size of the concave portion of the parison 5 and the sharpness of the opening cutting blade 27 are improved. It can be selected appropriately according to the request.

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Tank main body outer wall 5 Parison 5a Recessed part 10 Tank opening part 11 Opening cylindrical part 12 Opening part bending part 17 Open cutting part 20 Blow molding die 22 Cutting part holding part 23 Blow pin 25 Slide type 27 Open cutting blade 29 Gap for cutting 30 Gap opening / closing member

Claims (11)

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, an opening cutting blade that is slidable in and out of the cavity through the cutting gap portion, and the cut portion holding portion is provided. A blow pin that can slide inside and outside the cavity is provided,
After the parison is brought into close contact with the opening cylindrical portion forming portion and the opening excision portion, the blow pin is slid and penetrated through the parison, and then air is blown from the blow pin into the cavity, and the parison Cool the
After cooling the parison, the opening cutting blade is slid from the cutting gap, the cutting blade tip is rotated by a predetermined angle, and the parison of the opening excision is excised. A method for forming an opening of a blow molded product. After cooling the parison, the predetermined angle for sliding the opening cutting blade from the cutting gap and rotating the cutting blade tip is about 360 degrees when there is one opening cutting blade. The method for forming an opening of a blow-molded product according to claim 1, wherein when there are a plurality of opening cutting blades, the total of the plurality of rotation angles is about 360 degrees. The method for forming an opening of a blow molded article according to claim 1 or 2, wherein a time for sending air from the blow pin into the cavity is 30 to 60 seconds. 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 product according to any one of claims 1 to 3. A gap opening / closing member capable of opening and closing the cutting gap is provided, and after the cutting gap is closed with the gap opening / closing member, a parison is introduced into the blow mold, and the parison is opened with the opening cylinder. After closely adhering to the shape forming part and the opening excision part, the gap opening / closing member is slid to open the cutting gap part, and the opening cutting blade is slid from the cutting gap part to cut the cutting part. The blow-molded product opening forming method according to any one of claims 1 to 4, wherein the parison of the opening cutting portion is cut by a blade tip portion. A gap opening / closing member capable of opening and closing the cutting gap is provided, and after the cutting gap is closed with the gap opening / closing member, a parison is introduced into the blow mold, and the parison is opened with the opening cylinder. After close contact with the shaped part and the opening excision part, the opening cutting blade is inserted into the gap for cutting, and a recess is formed in the parison at the tip of the opening cutting blade. After sliding through the parison, air is blown into the cavity from the blow pin to cool the parison,
After cooling the parison, the opening cutting blade is slid from the cutting gap, the tip of the opening cutting blade is pierced into the concave portion of the parison, and the opening excision portion is formed at the tip of the opening cutting blade. The method for forming an opening of a blow molded product according to any one of claims 1 to 4, wherein the parison is cut out. After the parison is brought into close contact with the opening cylindrical portion forming portion and the opening excision portion, the opening cutting blade is inserted into the cutting gap, and a recess is formed in the parison at the tip of the opening cutting blade. After sliding the blow pin and penetrating the parison, air is blown from the blow pin into the cavity to cool the parison,
After cooling the parison, the opening cutting blade is once retracted from the cutting gap, and then the opening cutting blade is slid from the cutting gap, and the tip of the opening cutting blade is moved to the parison. The blow-molded product opening forming method according to any one of claims 1 to 4, wherein the parison of the opening cutting portion is cut out at the tip of the opening cutting blade by piercing the concave portion. A cutting gap is provided between the opening tubular portion forming portion and the cut portion holding portion, and an opening cutting blade is provided that can slide in and out of the cavity through the cutting gap, and the opening cutting blade Is inserted into the cutting gap, the cutting gap is closed with the opening cutting blade, a parison is introduced into the blow molding die, and the parison is formed with the opening tubular portion forming portion and the opening. After forming a recess in the parison at the tip of the opening cutting blade in close contact with the cutting blade, slide the blow pin through the parison, and then blow air from the blow pin into the cavity. Cool the parison above,
After cooling the parison, the opening cutting blade is once retracted from the concave portion of the parison, and then the tip of the opening cutting blade is pierced into the concave portion of the parison, and the tip of the opening cutting blade The blow-molded product opening forming method according to any one of claims 1 to 4, wherein the parison of the opening cut portion is cut. A gap for cutting is provided between the opening cylindrical part forming part and the cut-out holding part, an opening cutting blade that is slidable in and out of the cavity through the cutting gap is provided, and a gap opening / closing member is provided. After inserting into the gap for cutting and closing the gap for cutting with the opening and closing member for gap, and making the parison into a recess at the tip of the opening and closing member for gap, slide the blow pin to make the parison After penetrating, blow air from the blow pin into the cavity, cool the parison,
After the gap opening / closing member is retracted from the cutting gap, the tip of the opening cutting blade is stabbed into the recess of the parison, and the parison of the opening excision is cut by the tip of the opening cutting blade. The blow-molded product opening forming method according to any one of claims 1 to 4, wherein the blow-molded product is cut. The blow molding die is provided with a recess in the surface of the cavity adjacent to the cutting gap, and the parison is formed in the recess on the surface of the cavity when the parison is brought into close contact with the surface of the cavity. After the parison that is in close contact with the opening excision is made thin, the blow pin is slid, and the parison is pierced, and then air is blown from the blow pin into the cavity, and the parison is Cool,
The tip of the opening cutting blade is stabbed into a thin portion of the parison, and the parison of the opening cutting portion is cut off at the tip of the opening cutting blade. A method for forming an opening of a blow-molded article as described in 1. The blow-molded product opening forming method according to any one of claims 6 to 10, wherein a tip of the opening cutting blade is formed in an acute angle shape.