JP7030278B2 - Manufacturing method of inner fitting fitting parts, manufacturing method of intermediate parts for inner fitting fitting parts, and blow molding molds and intermediate parts for manufacturing inner fitting fitting parts. - Google Patents

Description

The present invention relates to a method for manufacturing an inner fitting fitting part in the manufacture of a molded part, a method for manufacturing an intermediate part for an inner fitting fitting part, and a mold, an intermediate part, and a cutting blade.

Conventionally, as a method for manufacturing a molded part, laminated blow molding in which a parison is sandwiched between pinch-off portions and molded has been used. For example, Patent Document 1 discloses a blow molding die provided with a convex pinch-off portion arranged on the surface of a pair of dies and sandwiching a parison hanging from a die and a skin material. ..

Japanese Unexamined Patent Publication No. 11-309773

However, when a cylindrical pipe for internal fitting is manufactured by the above-mentioned blow molding, for example, a streak-like dent along the parting line may occur around the pinched-off parting line. If this streak-shaped dented pipe is fitted into a hose or the like through which cooling water or the like flows, it is assumed that water leaks from the dented portion, so the fitting portion is smoothed by eliminating the dent. Is preferable. As an example of countermeasures, there is a method of scraping the outer circumference of the fitting part of the pipe over the entire circumference according to the amount of dent, but in that case, it is necessary to increase the wall thickness of the pipe including the scraping allowance, so the material cost There is a lot of waste in terms of processing time, etc., and it takes time and effort to control the wall thickness.

Therefore, in view of the above points, the present invention is an intermediate between a method for manufacturing an inner fitting fitting part and an inner fitting fitting part, which can manufacture an inner fitting fitting part having an improved outer surface smoothness by a simple method. It is an object of the present invention to provide a method for manufacturing a part, and a mold, an intermediate part, and a cutting blade.

The method for manufacturing an inner fitting fitting part of the present invention includes a step of molding with a blow molding die including a cavity and a pinch-off portion provided with a protrusion forming portion on the cavity side, and molding formed with the mold. It is characterized by including a step of removing the protrusion formed by the protrusion forming portion in the portion.

In the method for manufacturing an intermediate part for an inner fitting fitting part of the present invention, the protrusion forming portion is formed by molding with a blow molding die provided with a cavity and a pinch-off portion having a protrusion forming portion on the cavity side. It is characterized by including a step of obtaining a molded portion having a protrusion formed by the above.

The mold of the present invention is characterized by including a cavity and a pinch-off portion provided with a protrusion forming portion on the cavity side.

The intermediate part of the present invention is an intermediate part for an inner fitting fitting part, and has a columnar outer surface, and a protrusion having a parting portion at the tip thereof is formed on the outer surface. It is a feature.

According to the present invention, a method for manufacturing an inner fitting fitting part and a method for manufacturing an intermediate part for an inner fitting fitting part, which can manufacture an inner fitting fitting part having improved outer surface smoothness by a simple method, As well as molds, intermediate parts and cutting blades can be provided.

It is a figure which shows the fitting part which concerns on embodiment of this invention. It is a plane schematic diagram of the split mold which concerns on embodiment of this invention. It is sectional drawing of the mold in the III-III cross-sectional position of the split mold of FIG. 2 which concerns on embodiment of this invention. It is a perspective view of the cutting blade which concerns on embodiment of this invention. It is a figure which shows the cutting blade which concerns on embodiment of this invention, (a) is the front view which looked at the cutting blade from the main body side, (b) is the Vb-Vb cross section of the cutting blade of FIG. 4 (a). It is a figure. It is a figure which shows the manufacturing process of the intermediate part and the fitting part which concerns on embodiment of this invention. It is a figure which shows the manufacturing process of the intermediate part which concerns on embodiment of this invention, (a) shows the state which arranged the parison in the mold, (b) shows the state which the mold was molded. It is a figure which shows the manufacturing process of the intermediate part which concerns on embodiment of this invention, (a) shows the state which air flowed into the parison, and (b) shows the state which the mold was opened. It is a figure which shows the manufacturing process of the fitting part which concerns on embodiment of this invention, (a) shows the intermediate part immediately after molding by a mold, (b) shows the intermediate part which removed the blowing bag part. It is a figure which shows the cutting process of the intermediate part which concerns on embodiment of this invention, (a) shows the state which the intermediate part enters into a cutting blade, (b) shows how to cut the protrusion of the intermediate part. (C) shows a state in which the protruding portion of the intermediate part is cut to the reduced diameter portion side. It is a figure which shows the manufacturing process of the fitting part which concerns on embodiment of this invention, (a) shows the fitting part which removed the protrusion from the intermediate part, (b) is the figure which removed the protrusion from the intermediate part. Indicates a fitting part in which a part of the protrusion remains.

Hereinafter, embodiments for carrying out the present invention will be described. FIG. 1 is a diagram showing an inner fitting fitting part 41B manufactured by the manufacturing method of the present embodiment. The fitting component 41B is formed in a long cylindrical shape by using a mold 1 for blow molding and a cutting blade 30 described later. As shown in FIG. 1, the fitting component 41B can form a liquid or gas flow path by fitting a tubular component such as a hose H to the fitting portion 412. As shown in the enlarged view of the A portion of the fitting portion 412, the outer surface 412b is formed smoothly. Therefore, even if the hose H or the like is connected by internal fitting, it is possible to prevent leakage of liquid or gas flowing inside. Hereinafter, the mold 1 and the cutting blade 30 for manufacturing the fitting component 41B, and the manufacturing method of the intermediate component 41A formed in the process of manufacturing the fitting component 41B and the fitting component 41B using these will be described. do.

FIG. 2 is a schematic plan view of the split mold 10. FIG. 2 shows one end side of the long cavities 11, 12, and 13, and the other end side is omitted from the drawing. FIG. 3 is a cross-sectional view of the mold 1 at the III-III cross-sectional position of the split mold 10 of FIG. FIG. 3 shows one of the split molds 1 and the other split mold 20 facing the split mold 10.

In FIG. 2, the split mold 10 has concave arc-shaped cavities 11, 12, and 13. The cavity 11 is a large-diameter region for forming the main body portion 411 (shown in FIG. 1 and the like) of the fitting component 41B. The cavity 12 is a small-diameter region that is coaxially connected to the cavity 11 and forms a fitting portion 412 that is an end portion of the fitting component 41B. The cavity 13 is a region for forming a blowing bag portion 413 for arranging a needle or the like for sending air into the parison 40. As shown in FIG. 3, the cavity 22 of the split mold 20 is formed so as to have a symmetrical shape with the cavity 12 of the split mold 10. Although not shown, other cavities of the split mold 20 which are arranged to face the cavities 11 and 13 of the split mold 10 are also formed so as to have a symmetrical shape.

In FIG. 3, the cavities 12 and 22 are each formed in a concave arc shape having a substantially semicircular shape, and are formed so as to have a substantially circular shape as a whole in a molded state. The split dies 10 and 20 have pinch-off portions 14 and 24 on both outer edges of the cavities 12 and 22. Further, the split dies 10 and 20 have relief portions 15 and 25 for allowing the burr portions to escape to the outside of the pinch-off portions 14 and 24.

The pinch-off portions 14, 24 are the contact portions 141,241 that come into contact with the split dies 10 and 20 when the molds are clamped, and the inclined portions 142, 242 provided on the cavities 12, 22 side from the contact portions 141,241. And the inclined portions 143 and 243 provided on the escape portions 15 and 25 sides from the contact portions 141 and 241. The contact portions 141 and 241 of the present embodiment are formed flat. The inclined portions 142 and 242 are substantially V-shaped protrusions whose width in cross-sectional view gradually narrows toward the abutting portions 141 and 241 which are the meshing portions of the pinch-off portions 14 and 24 during mold clamping. Form a forming part. The valley portion of the protrusion forming portion of the present embodiment is formed at an obtuse angle by the inclined portion 142 and the inclined portion 242.

The relief portions 15 and 25 have narrow portions 151 and 251 and wide portions 152 and 252, and are formed in two stages of width. The narrow portion 151 is connected to the inclined portions 143 and 243 of the pinch-off portions 14, 24. Further, the wide portions 152 and 252 are connected to the narrow portions 151 and 251 via the inclined portions 153 and 253. The contact portions 141,241, the narrow portions 151,251, and the wide portions 152,252 can be formed so as to be substantially parallel to each other. Further, the width of the narrow portions 151 and 251 can be formed to be slightly wider than the width of the inner edge of the protrusion forming portion formed by the inclined portions 142 and 242. Further, the width of the narrow portions 151 and 251 does not excessively regulate the flow of the parison 40 to the relief portions 15 and 25 shown in steps S01 and S02 (FIGS. 7A and 7B) described later. In addition, when the wall thickness of the parison 40 is increased, it can be widened. Further, the width of the narrow portions 151 and 251 can be narrowed when the wall thickness of the parison 40 is reduced in order to promote the flow of the parison 40 into the cavities 12 and 22.

FIG. 4 is a diagram showing a cutting blade 30. 5 (a) is a front view of the cutting blade 30 as viewed from the main body 31 side, and FIG. 5 (b) is a cross-sectional view of Vb-Vb of the cutting blade 30 of FIG. 5 (a).

The cutting blade 30 has a main body portion 31 having an opening on the front end surface 31a side and a base end portion 32 connected to the main body portion 31 on the side opposite to the front end surface 31a. The main body portion 31 has a bottomed hollow portion 311 and is formed in a substantially cylindrical shape as a whole. An introduction portion 312 inclined in an R chamfer shape is provided on the inner edge 31b on the tip surface 31a side of the hollow portion 311.

In FIG. 5A, a groove portion 313 is formed linearly from the inner edge 31b to the outer edge 31c on the tip surface 31a of the main body portion 31. The groove portions 313 are provided at three locations around the central axis of the hollow portion 311 at substantially equal angles. Each groove portion 313 is formed in a substantially rectangular concave shape. The edge portion a on the clockwise side of the groove portion 313 in FIG. 5A is formed in the radial direction from the center of the hollow portion 311. The opposite edge b facing the edge a of the groove 313 is formed so as to be parallel to the edge a. As shown in FIG. 5B, the bottom portion of the groove portion 313 is inclined so as to become deeper toward the hollow portion 311 side. The edge portion a of the groove portion 313 functions as the blade portion 314. Further, on the outer surface of the main body portion 31, a concave groove 315 having a rectangular cross-sectional view as shown in FIG. 5B is formed over the circumferential direction.

The base end portion 32 is formed in a columnar shape and is formed so as to project from the main body portion 31 so as to be coaxial with the hollow portion 311. The cutting blade 30 is used by being rotationally driven in the counterclockwise direction of FIG. 5A at the time of use by connecting the rotation shaft to the base end portion 32 via a chuck or the like (not shown).

FIG. 6 is a diagram showing a manufacturing process of the intermediate part 41A and the fitting part 41B. In steps S01 to S05, the intermediate part 41A can be manufactured by blow molding, and in steps S01 to S06, the fitting part 41B can be manufactured by blow molding and cutting. Hereinafter, each step (steps S01 to S06) will be described with reference to FIGS. 7 to 11.

First, in step S01, the parison 40 formed of the thermoplastic material is placed between the cavities 12 and 22 of the split molds 10 and 20 of FIG. 7 (a). The parison 40 is arranged over the cavities 11, 12, and 13 shown in FIG. 2 (a). The parison 40 can be molded by an appropriate extrusion molding device or the like. Further, the parison 40 of the present embodiment has an outer diameter larger than the inner diameter of the cavities 12 and 22, and is arranged over the relief portions 15 and 25 on both sides of the cavities 12 and 22.

In step S02, the mold 1 is molded. Then, the periphery of the outer portions 40a and 40b of the parison 40 separated from each other is sandwiched by the pinch-off portions 14 and 24, and the contact portions 141 and 241 mesh with each other to separate the molding portion 41 and the burr portion 42 (. See FIG. 7 (b)). Further, a part of the parison 40 sandwiched between the pinch-off portions 14 and 24 flows toward the cavities 12 and 22, and the other part flows inside the relief portions 15 and 25 toward the wide portions 152 and 252. ..

Since the burr portion 42 is sandwiched between the narrow portions 151 and 251 having a large flow path resistance, the burr portion 42 excessively flows in the relief portions 15 and 25 when the pinch-off portions 14 and 24 sandwich the parison 40. Can be prevented. Therefore, it is possible to reduce the occurrence of sink marks on the inner peripheral surface of the molded portion 41 corresponding to the pinch-off portions 14 and 24, and it is possible to prevent the thickness of the molded portion 41 from becoming thin and the strength from being lowered. The portion of the burr portion 42 that cannot be accommodated in the narrow portions 151 and 251 can be flowed into the wide portions 152 and 252.

In step S03, air is flowed into the molded portion 41 of the parison 40 to form the molded portion 41 into an outer shape along the inner walls of the cavities 12 and 22 (see FIG. 8A). Air can be introduced from the parison 40 arranged on the cavity 13 side shown in FIG. 2 by inserting or piercing a needle for blow-up. When the pressure in the molded portion 41 increases, the molded portion 41 is urged to the inner surfaces of the cavities 12 and 22, and the difference in wall thickness of the molded portions 41 decreases. Further, on the outer surface 412b of the molded portion 41, the protrusions 412a are formed by the protrusions (inclined portions 142, 242).

In step S04, the mold 1 is opened, and the molding portion 41 and the burr portion 42 are separated from the split molds 10 and 20 and removed. FIG. 9A shows a molded portion 41 in a die-cut state. The molding portion 41 has a main body portion 411, a fitting portion 412, and a blowing bag portion 413. The main body portion 411 is formed by the cavity 11, the fitting portion 412 is formed by the cavity 12, and the blow bag portion 413 is a portion formed by the cavity 13.

In step S05, of the molding portions 41 shown in FIG. 9A, the blowing bag portion 413 side on which the needle is arranged is cut at the cutting position CL including a part of the protrusion 412a, and FIG. 9B is shown. The intermediate part 41A for the inner fitting fitting part shown in the above is taken out. The intermediate component 41A of the present embodiment is formed in a long cylindrical shape, and a fitting portion and a blowing bag portion can be similarly configured on the other end side. The illustration of the other end side of the intermediate component 41A is omitted.

In FIG. 9B, the intermediate component 41A has a main body portion 411 and a fitting portion 412, and is formed in a substantially cylindrical shape as a whole. The fitting portion 412 is connected to the main body portion 411 via a diameter-reduced portion 411a formed by an inclined portion 11a (see FIG. 2) of the split mold 10 and an inclined portion (not shown) of the split mold 20. Will be set up. A protrusion 412a having a substantially isosceles triangular cross section is formed on the outer surface 412b of the fitting portion 412. Each protrusion 412a is formed from the tip 412c of the fitting portion 412 to the reduced diameter portion 411a.

As shown in FIG. 3 and the like, the bottom portion of the protrusion forming portion (inclined portions 142, 242) is formed at an obtuse angle. Therefore, the protrusion 412a is formed in a substantially isosceles triangle shape with the outer surface 412b side as the base 51 and the top 53 as an obtuse angle in the front view where the cut surface shown in the enlarged view of the B portion appears.

The parting portion PL of the intermediate component 41A is formed over the main body portion 411 and the fitting portion 412. Further, the parting portion PL of the fitting portion 412 is formed along the ridge which is the top portion 53 of the protrusion portion 412a. A concave groove 531 is formed on the upper side and the lower side of the parting portion PL. For example, when the parison 40 is cut off by the pinch-off portions 14, 24, the two concave grooves 531 are in contact with the periphery of the bottom of the protrusion forming portion (inclined portions 142, 242) of the parison 40, and the region where hardening has progressed. A part of the parison 40 that is pushed toward the cavities 12 and 22 and dents, and then flows out from between the pinch-off portions 14 and 24 that are connected to the center of the dent until just before cutting, protrudes with the parting portion PL at the tip. It is considered to be formed by curing in a state. The concave groove 531 is formed along the ridge of the protrusion 412a, similarly to the parting portion PL. The protrusion 412a is formed so as to be higher than the depth of the concave groove 531. Therefore, the fitting portion 412 can be formed in a cylindrical shape as a whole, and it is possible to prevent the concave groove 531 from being formed on the outer surface 412b of the cylindrical shape.

In step S06, the protrusion 412a of the fitting portion 412 is cut off. Here, the cutting process of the intermediate part 41A, which is the part to be machined in step S06, will be described with reference to FIG.

FIG. 10A shows how the intermediate part 41A is inserted into the cutting blade 30. Regarding the cutting blade 30, the XX cross section of the cutting blade 30 in FIG. 5A is shown. First, the cutting blade 30 is rotated in the counterclockwise direction when viewed from the main body 31. Then, the fitting portion 412 of the intermediate component 41A is made to enter the hollow portion 311. At this time, the intermediate component 41A is centered by the introduction unit 312. The inner diameter of the inner surface 311a on the tip surface 31a side of the hollow portion 311 is formed to be substantially the same as the outer diameter of the outer surface 412b of the fitting portion 412. The inner diameter of the inner surface 311b on the base end portion 32 side of the hollow portion 311 is formed to be larger than the inner diameter of the inner surface 311a on the front side.

FIG. 10B shows a state in which the protrusion 412a of the intermediate part 41A is cut. When the fitting portion 412 is inserted into the hollow portion 311, the protrusion 412a protruding radially outward from the outer surface 412b enters the rotation trajectory of the blade portion 314 of the cutting blade 30, so that the protrusion 412a is a blade portion. It is cut off from the tip 412c side by 314. When the intermediate component 41A is further advanced toward the inside of the hollow portion 311, the protrusion 412a on the reduced diameter portion 411a side is also cut off. The fitting portion 412 from which the protrusion 312a is removed and the outer surface 412b is smoothed moves sequentially into the hollow portion 311.

FIG. 10C shows a state in which the protrusion 412a of the intermediate part 41A is cut to the reduced diameter portion 411a side. When the intermediate part 41A is moved to a position where the tip surface 31a of the main body 31 and the reduced diameter portion 411a of the intermediate part 41A are close to each other, substantially all of the protrusions 412a in the fitting portion 412 are removed, and the fitting portion 412 is removed. The outer side surface 412b is in a smooth state. Similarly, the fitting portion on the other end side of the intermediate component 41A opposite to the fitting portion 412 can be machined so that the outer surface becomes smooth by the cutting blade 30.

FIG. 11A is a diagram showing a fitting part 41B manufactured by the manufacturing method according to the present embodiment. The fitting part 41B is a part from which the protrusion 412a has been cut off in step S06. The fitting portion 412 of the fitting part 41B, which is a finished product, has a smooth outer surface 412b without the concave groove 531 because the protrusion 412a having the concave groove 531 is cut. Therefore, when the fitting component 41B is internally fitted to the hose H formed of a soft member such as rubber, it is possible to prevent the generation of a gap between the inner surface and the outer surface 412b of the hose H.

As described above, according to the present embodiment, the mold 1 for molding the fitting portion 41B has a streak on the outer surface 412b of the fitting portion 412 by forming the parting portion PL on the protrusion 412a of the fitting portion 41B. It is possible to prevent the formation of a dent in the shape and reduce the occurrence of sink marks on the inner surface of the fitting component 41B in the parting portion PL. Further, since the fitting portion 412 can be accurately positioned by the introduction portion 312 provided in the opening of the cutting blade 30 at the time of cutting, the centering of the intermediate part 41A, which is a hollow part, is facilitated, and the rotating cutting blade 30 The blade portion 314 provided in the slit-shaped groove portion 313 can remove the protrusion portion 412a without deeply cutting the outer surface 412b. The fitting part 41B having the fitting portion 412 formed in this way can easily manufacture the inner fitting fitting part 41B having improved smoothness on the outer surface by a simple process. Even when the hose H is connected to the fitting component 41B, it is possible to prevent the occurrence of leakage of gas or liquid flowing inside.

Further, according to the present embodiment, the outer surface 412b of the fitting portion 412, which is the end portion of the fitting portion 41B, can be smoothed by partial processing only around the parting portion PL, so that the generation of cutting chips is excluded. It can be reduced as compared with the case where the entire circumference of the side surface 412b is cut. Further, since it is not necessary to thicken the molding portion 41 in advance for cutting the outer surface 412b, the use of the molding material can be saved.

Further, in the present embodiment, since the introduction portion 312 is provided on the cutting blade 30, it is easy to position the parts to be machined. Therefore, in order to use it as a guide for centering when cutting the outer shape, it is possible to omit the primary machining inside the cylinder of the part to be machined. By omitting the primary processing inside the product, it is possible to prevent cutting chips from being mixed inside the product.

The cross-sectional shape of the protrusion 412a may have a top 53 at a substantially right angle or an acute angle, but it is desirable that the top 53 has an obtuse angle. As the angle of the top portion 53 becomes smaller, the side surface 52 of the protrusion 412a shown in FIG. 9B approaches the outer surface 412b perpendicularly. Then, the portion where the side surface 52 and the blade portion 314 come into contact with each other during cutting approaches the surface contact, and the resistance applied to the cutting blade 30 increases. On the other hand, as shown in the present embodiment, when the top portion 53 is formed at an obtuse angle, the side surface 52 having a small inclination angle of the protrusion 412a approaches parallel to the outer surface 412b. Then, the portion where the side surface 52 and the blade portion 314 come into contact with each other during cutting approaches line contact or point contact, and the resistance applied to the cutting blade 30 can be reduced.

Further, in the step of cutting and removing the protrusion 412a in step S06, when the intermediate part 41A is brought into the inner surface 311a of the cutting blade 30, it is assumed that the protrusion 412a is left uncut due to the centering being slightly displaced. FIG. 11B shows a fitting part 41B in which the protrusion 412a is removed from the intermediate part 41A and a part of the protrusion 412a remains. As shown in the enlarged view of the C portion when the fitting portion 412 is viewed from the tip 412c side, a part of the protrusion 412a on the bottom 51 side remains as the residual portion 54. The residual portion 54 is formed in a thin substantially trapezoidal shape with the cutting surface 541 as the upper bottom in the front view. Step portions 542 are formed at the upper and lower ends of the residual portion 54.

It is desirable that the protrusion 412a is formed so that the angle formed by the outer surface 412b and the side surface 52 is large. When the angle between the outer side surface 412b and the side surface 52 is large (for example, an angle of 135 ° or more), the residual portion 54 is inconspicuous as a cutting mark, and the fitting part 41B is attached to the hose H formed of a soft member such as rubber. When the inner fitting is performed, the concave groove is directly formed on the outer surface 412b, or the residual portion 54 having a small angle between the outer surface 412b and the side surface 52 (for example, an angle smaller than 135 °) is formed. The adhesion between the inner surface and the outer surface 412b of the hose H is improved, and the occurrence of a gap can be reduced. In such a case, even the fitting component 41B having the residual portion 54 can prevent leakage of the liquid or the like flowing inside.

Further, the concave groove 531 is formed at the time of molding of the molding portion 41 in which two parisons 40 are sandwiched between the pinch-off portions 14 and 24 of the mold 1. Since the depth of the concave groove 531 becomes deeper as the wall thickness of the fitting portion 412 increases, it is desirable that the protrusion 412a also increases in proportion to the wall thickness of the fitting portion 412.

The protrusion 412a can be formed large by increasing the protrusion forming portions (inclined portions 142, 242 in FIG. 3) provided in the pinch-off portions 14, 24. If the protrusion 412a is too small compared to the wall thickness, the concave groove 531 penetrates the protrusion 412a and reaches the outer surface 412b, and the concave groove 531 remains and fits only by cutting and removing the protrusion 412a. The outer surface 412b of the joint portion 412 cannot be smoothed. On the other hand, if the protrusion 412a is too large compared to the wall thickness, the sink marks generated on the inner peripheral surface corresponding to the position of the protrusion 412a of the fitting portion 412 become large, and a part of the fitting portion 412 becomes thin. When the protrusion 412a is cut off, it is assumed that cracks or chips may occur on the outer surface 412b. Further, if the protrusion 412a is large, the amount of scraping of the protrusion 412a increases. In consideration of such a condition, the protrusion 412a can be set in a range of a size higher than the depth of the concave groove 531.

For example, the height of the protrusion 412a can be made smaller than the wall thickness in a range larger than the depth of the concave groove 531 such as about half the wall thickness of the fitting portion 412. Further, the length of the bottom 51 of the protrusion 412a is equal to or larger than the wall thickness of the fitting portion 412 within the range in which the protrusion 412a having the obtuse angle of the top 53 can be formed on the outer surface 412b. be able to.

Further, in the present embodiment, an example of manufacturing a cylindrical inner fitting fitting part 41B such as a hose joint has been described, but a method of smoothing the outer surface of a rod-shaped body whose inside is not hollow in a rotating shaft, a connecting shaft, or the like. May be applied to. For example, instead of steps S01 to S03, the thermoplastic material is injected into the molded split dies 10 and 20, and then the fitting parts are subjected to the same steps as in steps S04 to S06 of the present embodiment. It may be manufactured. As described above, the fitting member manufactured by the method using the mold 1 and the cutting blade 30 can be used, for example, as an engaging portion for connecting a plurality of parts to each other. Then, since the gap between the engaging portions of the engaging portion can be reduced, the connection strength between the plurality of parts can be increased.

Further, in the split dies 10 and 20, the inclined portions 142 and 242 may be provided on a part on the cavity 13 side, and the protrusion 412a may be formed on a part on the tip 412c side of the fitting portion 412.

Further, although the introduction portion 312 of the cutting blade 30 has an R chamfer shape, the introduction portion 312 is formed inside the hollow portion 311 in a tapered shape such as a C chamfer shape that is inclined in a substantially linear cross-sectional view. You may.

Moreover, the embodiment described above is presented as an example, and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and variations thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Mold 10,20 Divided mold 11 Cavity 11a Inclined part 12,22 Cavity 13 Cavity 14,24 Pinch-off part 15,25 Relief part 30 Cutting blade 31 Main body part 31a Tip surface 31b Inner edge 31c Outer edge 32 Base end part 40 Parison 40a Outer part 40b Outer part 41 Molding part 41A Intermediate part 41B Fitting part 42 Burr part 51 Bottom side 52 Side 53 Top part 54 Remaining part 141,241 Contact part 142,242 Inclined part 143,243 Inclined part 151,251 Narrow part 152 , 252 Wide part 153,253 Inclined part 311 Hollow part 311a Inner surface 311b Inner surface 312 Introductory part 313 Groove part 314 Blade part 315 Concave groove 411 Main body part 411a Reduced diameter part 412 Fitting part 412a Protrusion part 412b Outer side surface 412c 531 concave groove 541 cutting surface 542 stepped part H hose PL parting part a edge part b edge part

Claims (7)

A step of molding with a blow molding die including a cavity and a pinch-off portion provided with a protrusion forming portion on the cavity side.
A step of removing the protrusion formed by the protrusion forming portion in the molding portion molded by the mold, and
A method of manufacturing an inner fitting fitting part, which comprises. The molded portion has a columnar outer surface on which the protrusion is formed, and the molded portion has a columnar outer surface.
The step of removing the protrusion is a rotating cutting blade provided with a tubular main body having an inner diameter of the same diameter as the outer surface and a blade provided in the radial direction on the tip surface of the main body. The molding portion is inserted into the inside of the
The method for manufacturing an inner fitting fitting component according to claim 1, wherein the inner fitting fitting component is manufactured. The method for manufacturing an inner fitting fitting part according to claim 1 or 2, wherein the protrusion has a triangular shape in a cross-sectional view. The mold has a narrow portion connected to the pinch-off portion and the outside, and a wide portion connected to the narrow portion.
The narrow portion causes a part of the parison to flow toward the cavity when the parison is cut at the pinch-off portion.
The method for manufacturing an inner fitting fitting part according to any one of claims 1 to 3, wherein the inner fitting fitting part is manufactured. 2. A method for manufacturing intermediate parts for internal fitting fitting parts. With a long cavity,
A pinch-off portion provided with a V-shaped protrusion forming portion in which a valley portion is formed at an obtuse angle on the outside of the cavity in a cross-sectional view orthogonal to the long direction .
A relief portion for allowing the burr portion to escape, which is provided outside the pinch-off portion in a cross-sectional view orthogonal to the long direction, and a relief portion.
Blow molding dies for manufacturing inward fitting fitting parts, characterized by: An intermediate part for internal fitting fitting parts,
Has a columnar outer surface,
A protrusion having a parting portion at the tip is formed on the outer surface.
An intermediate part characterized by that.

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