JP6986585B2 - Cylindrical parts molding equipment and methods for manufacturing tubular parts - Google Patents

Description

The present invention relates to a tubular part molding apparatus by a suction blow molding method and a method for manufacturing a tubular molded part.

Patent Document 1 discloses a technique relating to a suction blow molding method. After arranging the parison, which is a resin material, in the mold, air is blown into the parison. Then, the parison expands and is formed into the shape of the cavity provided in the mold. According to the suction blow molding method, a cylindrical part that is hollow and has a two-dimensional or three-dimensional shape can be easily manufactured.

Japanese Unexamined Patent Publication No. 2007-245443

For molded parts, care must be taken when separating the molded parts and the mold. For example, the mold may be provided with a so-called draft in order to easily separate the molded part from the mold. However, in the case of a molded part having an uneven structure on the outer surface, the draft may not be sufficient. In that case, the mold may be composed of a plurality of parts and each part may be moved in a direction in which it is easy to pull out. Further, after moving the mold in a predetermined direction, the mold may be moved in a direction different from the predetermined direction. However, even when the mold is composed of a plurality of parts or when the mold is separated while being moved in a plurality of directions, the mold cost increases and the molding machine becomes complicated. .. Therefore, in the art, there is a demand for a technique that can easily separate a molded part and a mold even if the molded part has an uneven structure on the outer surface.

Therefore, the present invention provides a tubular part molding apparatus and a method for manufacturing a tubular molded part that can easily separate a molded part and a mold even if the molded part has an uneven structure on the outer surface.

One embodiment of the present invention is a tubular part molding apparatus for manufacturing a tubular molded part by a suction blow method, which is a mold unit provided with a cavity that serves as a mold for the molded part, and a parison for the molded part. The mold unit is provided with a parison supply unit for supplying the mold unit and a blow unit for molding the parison into a molded part by expanding the parison supplied to the cavity, and the mold unit has a first mold and a second mold. It has a mold, and the first mold and the second mold have a cavity portion for forming a molded part and a cavity portion for forming a spiral convex structure formed on the inner peripheral surface of the molded part. A convex portion provided in a spiral shape so as to protrude from the inner peripheral surface of the mold, and a concave portion provided on the convex portion at a position corresponding to the joint between the first mold and the second mold. Including each.

In this device, the first mold and the second mold constituting the mold unit have a convex portion provided in a spiral shape. As a result, it is possible to mold a molded part having a spiral groove formed on the outer peripheral surface. Further, the convex mold portion is provided with a concave mold portion at a position corresponding to the joint between the first mold and the second mold. According to this concave portion, a part of the convex portion that is caught in the spiral groove is scraped. As a result, the molded parts can be removed from the first mold and the second mold by simply moving the first mold and the second mold in one direction without causing significant damage to the molded parts. That is, this device can easily separate the molded part and the mold even if the molded part has an uneven structure on the outer surface.

In one embodiment, the width of the convex portion may be shorter than the pitch of the convex portion in the direction of the axis of the cavity portion. According to this configuration, the molded part and the mold can be better separated.

In one embodiment, the concave portion may be located between the inner peripheral surface of the cavity portion and the ridgeline of the convex portion in the radial direction of the cavity portion. This configuration also allows the molded part and the mold to be better separated.

In one form, the cross-sectional shape of the convex portion may be a triangle whose base is longer than the height. This configuration also allows the molded part and the mold to be better separated.

Another aspect of the present invention is a method of manufacturing a tubular molded part having a tubular shape and having a spiral convex structure formed on the inner peripheral surface thereof by using a tubular component molding apparatus. The process of preparing a mold unit having a mold and a second mold, the process of butting the second mold against the first mold to form a cavity for a tubular part, and the material of the molded part in the cavity. It has a step of arranging a certain parison and a step of molding the parison into a molded part by expanding the parison supplied to the cavity, and the first mold and the second mold form the molded part. In order to form the cavity portion and the spiral convex structure formed on the inner peripheral surface of the molded part, the convex portion provided in a spiral shape so as to protrude from the inner peripheral surface of the cavity portion, and the first Each includes a concave mold portion provided on the convex mold portion at a position corresponding to the joint between the mold and the second mold. According to this manufacturing method, a molded part having a spiral concavo-convex structure on the inner peripheral surface and the outer peripheral surface can be easily manufactured.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a tubular part molding apparatus and a method for manufacturing a tubular molded part, which can easily separate a molded part and a mold even if the molded part has an uneven structure on an outer surface.

FIG. 1 is a diagram schematically showing a main configuration of a suction blow molding apparatus of an embodiment. FIG. 2 is a perspective view showing a molded part manufactured by the suction blow molding apparatus of FIG. 1. FIG. 3 is an enlarged plan view showing a main part of the molded part of FIG. 2. FIG. 4 is an enlarged perspective view showing the inner peripheral surface of the molded part of FIG. 2. FIG. 5 is an exploded perspective view showing the molded part of FIG. 2 and the mold unit. FIG. 6 is an enlarged perspective view showing a main part of the mold unit of FIG. FIG. 7 is a flow chart showing a main process of a method for manufacturing a tubular molded part.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description is omitted.

<Suction blow molding equipment>
FIG. 1 schematically shows a main configuration of a suction blow molding apparatus 1 (cylindrical part molding apparatus) according to an embodiment. The suction blow molding apparatus 1 molds a tubular molded part by a suction blow method. The suction blow molding apparatus 1 includes a parison supply unit 2, a blow unit 3, and a mold unit 10.

The parison supply unit 2 supplies the parison 200, which is a raw material of the tubular molded part 100 (see FIG. 2), to the mold unit 10. The parison supply unit 2 melts the resin material contained in the hopper. Then, the melted resin material is discharged while being formed into a cylinder, for example. The discharged parison 200 is dropped into the cavity 10C from the receiving port 10a of the mold unit 10. At this time, the suction portion 2a sucks out the air inside the cavity 10C from the suction port 10b on the opposite side of the receiving port 10a (suction). By this suction, the parison 200 is guided from the receiving port 10a of the mold unit 10 to the suction port 10b.

Examples of the material of the molded component 100 include PP (polyamide), PE (polyamide), PA6 (polyamide 6), PA66 (polyamide 66), PA610 (polyamide 610), PA12 (polyamide 12), PA612 (polyamide 612), and PPS. (Polyphenylene sulfide resin), PBT (polybutylene terephthalate resin), TPEE (polyester-based thermoplastic elastomer) and the like may be used. Further, these materials may contain additives and strengthening agents such as glass.

The blow unit 3 supplies compressed air to the inside of the parison 200 arranged in the cavity 10C. The blow portion 3 has an air supply portion 3a for supplying compressed air, and a closing portions 3b and 3c for closing both ends of the parison 200. When compressed air is supplied (blowed) to the parison 200 whose both ends are closed, the parison 200 expands and is pressed against the inner surface forming the cavity 10C. As a result, the shape of the inner surface forming the cavity 10C is transferred to the parison 200.

The mold unit 10 forms a cavity 10C that serves as a mold for the outer shape of the molded component 100. The mold unit 10 of the embodiment is for manufacturing a molded part 100 such as a pipe. The mold unit 10 has a first mold 10A and a second mold 10B. The cavity 10C is formed by contacting and pressing the first contact surface 10Aa of the first mold 10A and the second contact surface 10Ba of the second mold 10B with each other. The first mold 10A and the second mold 10B reciprocate in the normal direction of the first contact surface 10Aa and / or the second contact surface 10Ba by the drive mechanism 4. The drive mechanism 4 brings the first mold 10A and the second mold 10B into close contact with each other at the time of supplying the parison 200 and at the time of blow molding. Further, the drive mechanism 4 separates the first mold 10A and the second mold 10B from each other when the molded part 100 is taken out. It suffices if the drive mechanism 4 of the embodiment can basically reciprocate in one direction. However, the drive mechanism 4 may have a function of moving the first mold 10A and the second mold 10B in different directions.

<Molded parts>
Here, the molded part 100 molded by the mold unit 10 will be described in detail. FIG. 2 is a perspective view of the molded part 100. The molded component 100 is, for example, a pipe mounted on a vehicle. Piping has a two-dimensional or three-dimensional complex shape. The molded part 100 shown in FIG. 2 has four bent portions 101a and 101b. In the molded component 100, a straight pipe portion 102 is formed between the pair of bent portions 101a, and a spiral structure is formed in the straight pipe portion 102.

The structure of the outer peripheral surface of the straight pipe portion 102 will be described with reference to FIG. On the outer peripheral surface, a concave spiral groove is formed from the outer peripheral surface. Further, as will be described in detail later, a spiral convex portion protruding from the inner peripheral surface is formed on the inner peripheral surface of the straight pipe portion 102. The groove and the convex portion correspond to each other, and the convex portion protrudes from the inner peripheral surface by the amount of the recessed portion by the groove. In the following description, the groove provided on the outer peripheral surface is referred to as "spiral concave structure 110". On the other hand, the convex portion provided on the inner peripheral surface is called "spiral convex structure 120".

The spiral concave structure 110 is formed by the convex portion 12 of the mold unit 10 described later. The cross section of the spiral concave structure 110 is a triangle as shown by the two-dot chain line in FIG. The base of this triangle corresponds to the outer peripheral surface, and a pair of hypotenuses extend toward the axis A of the straight pipe portion 102. For example, the triangle may be an isosceles triangle. Then, the vertices of the triangle form the bottom of the spiral concave structure 110. This bottom has a spiral shape. Further, the width of the base width of 110W is longer than the height of the triangle of 110H (that is, the depth of the groove). In other words, the angle between the base and the hypotenuse is an acute angle. The long angle of the triangle is an obtuse angle. According to such a cross-sectional shape, a part of the mold unit 10 fitted in the spiral concave structure 110 can be easily separated.

In the spiral concave structure 110, not only the cross-sectional shape of the groove but also its pitch 110P is important. The pitch 110P is, for example, a distance that the spiral concave structure 110 moves in the direction of the axis A of the straight pipe portion 102 when the spiral concave structure 110 is rotated 360 degrees and extended. This pitch 110P is, for example, larger than the inner diameter of the straight pipe portion 102. Further, the pitch 110P is about the same as the width 110W of the spiral concave structure 110 or larger than the width 110W.

Here, immediately after blow molding, a part of the mold unit 10 is fitted in the spiral concave structure 110. Here, the spiral concave structure 110 is inclined with respect to the axis A of the straight pipe portion 102. Then, when the mold unit 10 is removed from the molded part 100, basically, the mold unit 10 should be moved in the extending direction of the spiral concave structure 110 (see arrow B1). This is because, for example, when the mold unit 10 fitted in the spiral concave structure 110 tilted with respect to the axis A is moved in the direction orthogonal to the axis A (see arrow B2), it gets stuck in the spiral concave structure 110. This is because a part of the mold unit 10 is pressed against the wall surface of the spiral concave structure 110. In this case, a part of the mold unit 10 moves while pressing the wall surface of the spiral concave structure 110 and deforming the wall surface. Then, the spiral concave structure 110 may be deformed or damaged when the pressing force is large.

The above phenomenon can be avoided by the relief convex portion 111. That is, if the mold unit 10 is moved in the direction orthogonal to the axis A (arrow B2), a part of the mold unit 10 that generates a pressing force enough to damage the spiral concave structure 110 is deleted. good. Such a portion is located in the vicinity of the joint 10S (see FIG. 1) of the first mold 10A and the second mold 10B constituting the mold unit 10. Removing a part of the mold unit 10 means that, when viewed from the side of the molded part 100, a convex portion is formed according to the scraped position of the mold unit 10. This convex portion is an escape convex portion 111. Therefore, a parting line is formed on the relief convex portion 111. In addition, in FIG. 2 and the like, the illustration of the parting line is omitted.

<Inner shape>
The structure of the inner peripheral surface of the molded component 100 will be described with reference to FIG. A spiral convex portion is formed on the inner peripheral surface. This convex portion is a spiral convex structure 120 as described above. The spiral convex structure 120 is provided on the inner peripheral surface of the straight pipe portion 102. The spiral convex structure 120 is for increasing the flow velocity of the liquid flowing through the straight pipe portion 102. The effect of increasing the flow velocity of the spiral convex structure 120 will be described later while showing the results of the fluid numerical analysis. The cross-sectional shape of the spiral convex structure 120 is a triangle. That is, the cross-sectional shape of the spiral convex structure 120 generally corresponds to the cross-sectional shape of the spiral concave structure 110. The cross-sectional shape of the spiral convex structure 120 is, for example, an isosceles triangle. The portion corresponding to the base of the triangle is the boundary between the spiral convex structure 120 and the straight pipe portion 102. Since the spiral convex structure 120 and the straight pipe portion 102 are integrally formed, there is no visible boundary line. Further, the height 120H of the triangle (height of the spiral convex structure 120) is lower than the base. The height 120H of the spiral convex structure 120 may be, for example, about 20% of the inner diameter of the straight pipe portion 102. Therefore, the angle formed by the base and the hypotenuse is an acute angle, and the apex angle is an obtuse angle. Further, a square radius 123 is formed between the pair of slopes 122 and the inner peripheral surface. Further, the relationship between the pitch 120P and the bottom of the spiral convex structure 120 generally corresponds to the relationship between the pitch 110P and the bottom of the spiral concave structure 110. For example, the pitch 120P of the spiral convex structure 120 may be the same as the pitch 110P of the spiral concave structure 110.

On the outer peripheral surface, a relief convex portion 111 for satisfactorily removing the mold unit 10 is provided. An inner peripheral recess 124 corresponding to the relief convex portion 111 may be formed at a position corresponding to the relief convex portion 111 on the inner peripheral surface. The relief convex portion 111 is positively formed according to the mold unit 10, but the inner peripheral concave portion 124 can be formed in association with the formation of the relief convex portion 111. Therefore, depending on the shape of the relief convex portion 111 and the wall thickness of the straight pipe portion 102, the inner peripheral concave portion 124 may be formed only slightly or may not be formed in a size that can be visually recognized.

<Mold unit>
Next, the mold unit 10 will be described in detail with reference to FIG. The mold unit 10 has a first mold 10A and a second mold 10B as main parts. The first mold 10A and the second mold 10B form a cavity 10C for the molded part 100. The first mold 10A has a first contact surface 10Aa and a first cavity portion 10Ac dug from the first contact surface 10Aa. Similarly, the second mold 10B has a second contact surface 10Ba and a second cavity portion 10Bc. The cavity 10C is formed by pressing the first contact surface 10Aa of the first mold 10A against the second contact surface 10Ba of the second mold 10B.

FIG. 6 shows an enlarged portion of the first mold 10A and the second mold 10B that forms the straight pipe portion 102 of the molded component 100. This portion is provided with an inner peripheral surface 11 for forming the outer peripheral surface of the molded component 100, and a convex portion 12 for forming the spiral concave structure 110 and the spiral convex structure 120. The convex portion 12 projects from the inner peripheral surface 11. The convex portion 12 is for the spiral concave structure 110 and the spiral convex structure 120. Therefore, the cross-sectional shape and arrangement correspond to the spiral concave structure 110 and the spiral convex structure 120. In particular, since the convex portion 12 directly contacts the surface of the spiral concave structure 110, the cross-sectional shape and arrangement of the convex portion 12 match the cross-sectional shape and arrangement of the spiral concave structure 110.

It has already been explained that a part of the first mold 10A and the second mold 10B is cut in order to easily remove the first mold 10A and the second mold 10B after blow molding. This scraped portion is called a concave portion 13. The convex mold portion 12 is continuously formed over the inner peripheral surface of the first mold 10A and the inner peripheral surface of the second mold 10B. The concave portion 13 is provided on a part of the convex portion 12. More specifically, the concave mold portion 13 is provided so as to sandwich the boundary between the first contact surface 10Aa of the first mold 10A and the second contact surface 10Ba of the second mold 10B. Further, since there are two boundaries between the first contact surface 10Aa and the second contact surface 10Ba, the concave portion 13 is provided at two places while the convex portion 12 goes around.

The concave portion 13 is formed by cutting a part of the convex portion 12. In the present embodiment, the cross section of the convex portion 12 is illustrated as a triangle (isosceles right triangle) as an example. The cross section of the convex portion 12 is not limited to this, and may have other shapes. For example, the cross section of the convex portion 12 may be a polygon such as a quadrangle, or may be a semicircular shape (curved surface shape) having no corner portion. Further, in the case of a polygon, a shape such as a square rounded portion may be formed at the corner portion. Then, the concave portion 13 is formed by scraping a part of the top portion of the convex portion 12. That is, with respect to the inner peripheral mold surface 11, the top portion 12a of the convex mold portion 12 is located closest to the inner peripheral side of the cavity 10C. The concave portion 13 is located between the inner peripheral surface 11 and the top portion 12a of the convex portion 12. For example, the concave portion 13 is provided by cutting the top portion 12a and the slope 122 of the convex portion 12, and does not reach the square rounded portion 14. The concave portion 13 may reach the square rounded portion 14 and be flush with the inner peripheral surface 11.

<Manufacturing process>
Next, a suction blow molding method using the suction blow molding apparatus 1 will be described with reference to FIG. 7. First, the mold unit 10 is prepared (step S10). Next, the first mold 10A and the second mold 10B are combined to form the cavity 10C (step S20). An additional step S15 may be performed between the step S10 and the process S20. The additional process S15 is a step of arranging the embedded parts. That is, it is a separate part from the molded part 100 in which a part or the whole is embedded in the molded part 100. In short, step S15 is a work step for so-called insert molding. Next, the parison 200 is filled by the parison supply unit 2 (step S30). Then, blow molding is performed by the blow unit 3 (step S40). After that, the drive mechanism 4 takes out the molded part 100 by separating the first mold 10A and the second mold 10B from each other (step S50). At this time, due to the effect of the relief convex portion 111, the movement of the first mold 10A and the second mold 10B for taking out the molded part 100 is sufficient to move in one direction.

<Action effect>
In the suction blow molding apparatus 1, the first mold 10A and the second mold 10B constituting the mold unit 10 have a convex mold portion 12 provided in a spiral shape. As a result, it is possible to mold a molded part having a spiral groove formed on the outer peripheral surface. Further, the convex mold portion 12 is provided with a concave mold portion 13 at a position corresponding to the joint between the first mold 10A and the second mold 10B. According to the concave portion 13, a part of the convex portion 12 that is caught in the spiral groove is scraped. As a result, the molded part 100 can be moved to the first mold 10A and the second mold 10B by simply moving the first mold 10A and the second mold 10B in one direction without causing significant damage to the molded part 100. Can be removed from. That is, the suction blow molding apparatus 1 can easily separate the mold unit 10 from the molded component 100 even if the molded component 100 has an uneven structure on the outer surface.

<Example: Flow velocity of spiral pipe>
In order to confirm the effect of the spiral convex structure, numerical fluid analysis was performed as Examples 1, 2 and 3. In addition, as Comparative Example 1, a fluid numerical analysis was also performed in the case where the spiral convex structure was not provided. In the computational fluid dynamics, the analysis models of Examples 1, 2, 3 and Comparative Example 1 were prepared, and the case where water was flowed through each analysis model was simulated. Then, the flow velocity when the flow rate of the supplied water was set to a large flow rate (60 L / min) and the flow velocity when the flow rate of the supplied water was set to a small flow rate (20 L / min) were calculated. The main parameters in the analysis models of Examples 1, 2, 3 and Comparative Example 1 are as follows.
Example 1: Inner diameter 9 mm, pitch of spiral convex structure 13.3 mm.
Example 2: Inner diameter 9 mm, pitch of spiral convex structure 26.6 mm.
Example 3: Inner diameter 9 mm, spiral convex structure pitch 39.9 mm.
Comparative Example 1: The inner diameter is 9 mm, and the spiral convex structure is not provided.

The analysis results (flow velocity) of Examples 1, 2, 3 and Comparative Example 1 were as follows.
Example 1: Large flow rate 28 m / sec, small flow rate 9 m / sec.
Example 2: Large flow rate 24 m / sec, small flow rate 8 m / sec.
Example 3: Large flow rate 19 m / sec, small flow rate 8 m / sec.
Comparative Example 1: Large flow rate 16 m / sec, small flow rate 5 m / sec.

As described above, in any of Examples 1, 2 and 3, it was confirmed that the flow velocity was higher than that of Comparative Example 1 having no spiral convex structure. It was also confirmed that the narrower the pitch of the spiral convex structure, the higher the effect.

1 ... Suction blow molding device (cylindrical part molding device), 2 ... Parison supply section, 3 ... Blow section, 10 ... Mold unit, 10A ... 1st mold, 10Aa ... 1st contact surface, 10Ac ... 1st cavity Part, 10B ... 2nd mold, 10Ba ... 2nd contact surface, 10Bc ... 2nd cavity part, 10C ... Cavity, 10S ... seam, 11 ... inner peripheral mold surface, 12 ... convex part, 12a ... top, 13 ... Concave part, 14 ... Square rounded part, 100 ... Molded part, 102 ... Straight pipe part, 110 ... Spiral concave structure, 111 ... Relief convex part, 120 ... Spiral convex structure, 124 ... Inner peripheral concave part, 200 ... Parison.

Claims (2)

A tubular part molding device that manufactures tubular molded parts by the suction blow method.
A mold unit provided with a cavity that serves as a mold for the molded part, and a mold unit.
A parison supply unit that supplies a parison for the molded part to the mold unit,
A blow portion for forming the parison into the molded part by expanding the parison supplied to the cavity is provided.
The mold unit has a first mold and a second mold.
The first mold and the second mold are
The cavity portion that forms the cavity and
In order to form a spiral convex structure formed on the inner peripheral surface of the molded part, a convex portion provided in a spiral shape so as to protrude from the inner peripheral surface of the cavity portion, and a convex portion.
A tubular part molding apparatus including a concave mold portion provided on the convex mold portion at a position corresponding to a joint between the first mold and the second mold. It is a method of manufacturing a tubular molded part having a cylindrical shape and a spiral convex structure formed on the inner peripheral surface thereof by using a tubular component molding device.
The process of preparing a mold unit having a first mold and a second mold, and
A step of abutting the second mold against the first mold to form a cavity for the tubular part, and
The process of arranging the parison, which is the material of the molded part, in the cavity,
It comprises a step of molding the parison into the molded part by expanding the parison supplied to the cavity.
The first mold and the second mold are
The cavity portion that forms the cavity and
In order to form a spiral convex structure formed on the inner peripheral surface of the molded part, a convex portion provided in a spiral shape so as to protrude from the inner peripheral surface of the cavity portion, and a convex portion.
A method for manufacturing a tubular molded part including a concave mold portion provided in the convex mold portion at a position corresponding to a joint between the first mold and the second mold.

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