JP6832085B2 - Hollow molded products and methods for manufacturing hollow molded products - Google Patents

Description

The present invention relates to a hollow molded product and a method for producing a hollow molded product.

In recent years, pipe joints, which are an example of hollow molded products, have been manufactured by injection molding of resin. In particular, as a method of manufacturing a pipe joint having a bent portion in a passage by injection molding of resin, a pair of pin-shaped inner mold tips are butted at the molding position of the bent portion in the cavity of the outer mold. , It is common to inject molten resin into the cavity and pull out a pair of inner molds from the molded product obtained by this. When this method is used, the shape of the inner corner wall surface inside the bend at the bend of the passage, which is formed by a pair of inner molds, is the shape of the passage extending straight from one passage opening, as in Patent Document 1, for example. It must have an angular protruding shape composed of a wall surface and the wall surface of the passage extending straight from the other passage opening. If the inner corner wall surface is formed into an undercut shape with a lower protrusion height toward the aisle axis than the angular protrusion shape by the pair of inner molds, the pair of inner molds can be pulled out from the molded product. This is because it cannot be done.

Japanese Unexamined Patent Publication No. 2010-190374

However, the inner corner wall surface of the bend of the passage of the pipe joint is composed of the wall surface of the passage extending straight from one passage opening and the wall surface of the passage extending straight from the other passage opening as described above. Further, in the case of an angular protruding shape, for example, there is a problem that the pressure loss becomes large as a result of turbulent flow occurring at a curved portion in the fluid flowing in the passage. Therefore, there has been a demand for a technique that can be easily manufactured by injection molding without being greatly restricted by the shape of the inner corner wall surface of the bent portion and can improve the degree of freedom in designing the inner corner wall surface of the bent portion.
In addition, similar problems have been encountered not only in pipe fittings but also in other hollow molded products.

The present invention is for solving the above-mentioned problems, and provides a hollow molded product and a method for manufacturing a hollow molded product, which can improve the degree of freedom in designing the inner corner wall surface of the bent portion. Is the purpose.

The hollow molded product of the present invention is a hollow molded product having a passage connecting the first passage port and the second passage port inside, and having a bent portion in which the passage axis is bent in the passage. , A hollow main body member forming a main body wall surface which is a part of the wall surface of the passage, and a portion of the wall surface of the passage excluding the main body wall surface which is fixed to the inner peripheral surface of the main body member. The insert member comprises an insert member constituting the insert wall surface, and the insert member has an inner corner wall surface forming a bending inner portion in the bent portion of the wall surface of the passage, and is formed of the hollow molded product. In the cross section along the passage axis, at least a part of the inner corner wall surface is continuous with the first tangent line at the connection point of the passage wall surface continuous from the first passage port with the inner corner wall surface and the second passage port. It is bent inside the virtual inner corner wall surface, which is composed of a second tangent line at a connecting point with the inner corner wall surface of the wall surface of the passage.
According to the hollow molded product of the present invention, the degree of freedom in designing the inner corner wall surface of the bent portion can be improved.

In the hollow molded product of the present invention, it is preferable that the main body member has an outer corner wall surface that constitutes a bent outer wall surface at the bent portion of the passage.
In this case, the insert member can be manufactured more easily.

The method for manufacturing a hollow molded product of the present invention is the method for manufacturing the above-mentioned hollow molded product, in which the insert member forming step of forming the insert member and the insert member are placed in the outer cavity. Along with setting, a pair of inner molds for molding the wall surface of the main body are arranged so as to face each other at positions facing the inner corner wall surface of the insert member, and the molten resin is injected into the cavity. It includes a main body member forming step of integrally molding the main body member with the insert member.
According to the method for manufacturing a hollow molded product of the present invention, the degree of freedom in designing the inner corner wall surface of the bent portion can be improved.

In the method for manufacturing a hollow molded product of the present invention, in the main body member forming step, the main body member is provided with an outer corner wall surface that constitutes a bent outer wall surface at the bent portion of the passage by the pair of inner molds. Once molded, it is suitable.
In this case, the insert member can be manufactured more easily.

According to the present invention, it is possible to provide a hollow molded product and a method for manufacturing a hollow molded product, which can improve the degree of freedom in designing the inner corner wall surface of the bent portion.

It is sectional drawing which shows one Embodiment of the hollow molded article of this invention. 2 (a) and 2 (b) are views of the insert members shown in FIG. 1 viewed from different angles. 3 (a) and 3 (b) are cross-sectional views showing different modified examples of the hollow molded product of FIG. 1, respectively. It is an exploded perspective view which shows the main part of the outer mold for molding an insert member for molding an insert member. It is a perspective view which shows the main part of the outer mold for molding an insert member of FIG. 4 in a state where the mold is closed. It is an exploded perspective view which shows the main part of the outer mold for molding a main body member for integrally molding a main body member with an insert member together with an insert member. FIG. 6 is an exploded perspective view showing a main part of an outer mold for molding a main body member of FIG. 6 together with an insert member in a state different from that of FIG. It is a side view which shows the main part of the outer mold for molding a main body member of FIG. 6 together with an insert member in a state where the mold is closed.

Hereinafter, embodiments of the hollow molded product according to the present invention and the method for producing the hollow molded product will be illustrated with reference to the drawings.

[Hollow molded product]
First, an embodiment of the hollow molded article of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a cross-sectional view showing a pipe joint 1 as a hollow molded product of the present embodiment. The pipe joint 1 shown in FIG. 1 can be suitably used for connection with, for example, a pipe for water supply / hot water supply. However, the pipe joint 1 of this example can be used for connecting to a pipe for any purpose, and can be used for passing a fluid such as any gas or liquid, not limited to water, inside.
The pipe joint 1 of this example has two passage ports 10a and 10b (also referred to as "first passage port 10a" and "second passage port 10b", respectively), which are inlets and outlets for fluids, and is the first. A passage 10 connecting the passage opening 10a and the second passage opening 10b is formed inside. The passage 10 between the first passage opening 10a and the second passage opening 10b has a bent portion 10c in which the passage axis O is bent. Here, the passage axis O refers to a line obtained by smoothing the central axis of the passage 10. That is, the fluid flowing in the passage 10 is turned around at the bent portion 10c. A passage from the first passage opening 10a to the bent portion 10c (hereinafter referred to as "first passage 10d") and a passage from the second passage opening 10b to the bent portion 10c (hereinafter referred to as "second passage 10e"). ".) And each extends straight.
The cross section of FIG. 1 is a cross section along the passage axis O of the pipe joint 1.

In the example of the figure, the pipe joint 1 is formed in an L shape, and the first passage 10d and the second passage 10e form a substantially right angle.
However, the first passage 10d and the second passage 10e may have an acute angle or an obtuse angle. Further, the pipe joint 1 may have three or more passage openings, in which case the passage between any pair of passage openings may have a bent portion. For example, the pipe joint 1 may have three passage openings and be formed in a T-shape or a Y-shape, or may have four passage openings and be formed in a cross shape. ..

The pipe joint 1 of this example is a hollow (tubular in this example) main body member 20 and a main body member 20 that form a part of the wall surface of the passage 10 between the first passage opening 10a and the second passage opening 10b. It includes an insert member 30 that is fixed to the inner peripheral surface and constitutes the remaining portion of the wall surface of the passage 10. In the following, among the wall surfaces of the passage 10 between the first passage port 10a and the second passage port 10b, the passage wall surface formed by the inner peripheral surface of the main body member 20 is referred to as a “main body wall surface”, and the insert member 30 is the inner circumference thereof. The passage wall surface (the portion of the wall surface of the passage 10 excluding the main body wall surface) formed by the surfaces is referred to as an "insert wall surface".
In this example, the main body member 20 and the insert member 30 are each made of resin, and each is formed by injection molding. Since the main body member 20 and the insert member 30 are each formed by injection molding, they are superior in strength as compared with the case where they are formed by, for example, blow molding, so that the degree of freedom in designing the pipe joint can be increased. ..

In the example of the figure, the main body member 20 extends over the entire length of the passage 10 and has an L shape. Further, the pipe joint 1 includes an outer member 40 fixed to the outer peripheral surface of the main body member 20 in the vicinity of the bent portion 10c, an end portion of the outer member 40 on the first passage opening 10a side, and an end on the second passage opening 10b side. A pair of caps 41, which are fitted into the portions from the outer peripheral side, are further provided. Then, at the end of the pipe joint 1 on the first passage opening 10a side and the end on the second passage opening 10b side, between the main body member 20 and the outer member 40 and the cap 41 spaced apart from each other on the outer peripheral side thereof. , 50a and 50b of annular insertion spaces for inserting a pipe connected to the pipe joint 1 are configured. In FIG. 1, the outer member 40 and the cap 41 are shown by broken lines.
In this example, the outer member 40 and the cap 41 are each made of resin.
However, the pipe joint 1 does not have to include the outer member 40 and the cap 41. In that case, the pipe joint 1 may be configured so that the pipe connected to the pipe joint 1 is inserted into the inner peripheral side of the main body member 20.

2 (a) and 2 (b) show the state when the insert member 30 of FIG. 1 is viewed from different angles. The insert member 30 of this example includes a tubular first tubular portion 32 extending straight, a tubular second tubular portion 33 extending straight in a direction substantially perpendicular to the first tubular portion 32, and the like. It has a connecting wall 31 that connects a part of the peripheral wall of the first tubular portion 32 in the circumferential direction and a part of the peripheral wall of the second tubular portion 33 in the circumferential direction. As shown in FIG. 1, the first tubular portion 32 constitutes a part of the pipe wall of the first passage 10d by its inner peripheral surface, and the second tubular portion 33 has a second passage by its inner peripheral surface. It constitutes a part of the pipe wall of 10e. Further, the surface of the connecting wall 31 facing the passage axis O side is curved smoothly and convexly toward the passage axis O, forming an inner corner wall surface 31a forming a wall surface inside the bend at the bent portion 10c. There is.

As shown in FIG. 2, the insert member 30 is open because the peripheral wall of the first tubular portion 32 and the peripheral wall of the second tubular portion 33 are not connected at a position facing the inner corner wall surface 31a of the connecting wall 31. It has an open portion 34. Along with this, in the pipe joint 1, as shown in FIG. 1, the main body member 20 has an outer corner wall surface 21 that constitutes a bent outer wall surface at the bent portion 10c.

As shown in FIG. 2B, in this example, a ridge 33a extending along the extending direction of the second tubular portion 33 is provided on the inner peripheral surface of the second tubular portion 33 of the insert member 30. ..

In this example, as shown in FIG. 1, in the cross section along the passage axis O of the pipe joint 1, at least a part (all in the example of the figure) of the inner corner wall surface 31a is a first passage continuous from the first passage opening 10a. The first tangent line L1 at the connection point with the inner corner wall surface 31a of the wall surface of 10d and the second tangent line L2 at the connection point with the inner corner wall surface 31a of the wall surface of the second passage 10e continuous from the second passage opening 10b. It is located inside the bend, rather than the virtual inner corner wall surface, which is composed of. Therefore, the inner corner wall surface 31a has an undercut shape.
In this example, in the cross section along the passage axis O of the pipe joint 1, at least a part of the inner corner wall surface 31a is bent inside the virtual inner corner wall surface, so that the fluid flowing in the passage is disturbed by the bent portion 10c. It is possible to suppress the generation of a flow, and thus the pressure loss can be reduced.
Further, in the pipe joint 1 of this example, the wall surface inside the bend at the bent portion 10c is composed of the insert member 30 instead of the main body member 20. With such a configuration, as will be described later, when the pipe joint 1 is manufactured by injection molding, it is possible to form an inner corner wall surface 31a having an undercut shape, which has not been realized in the past, and by extension, the pipe joint. The degree of freedom in design is improved.

In addition, the pipe joint 1 of this example can be variously modified as long as at least a part of the inner corner wall surface 31a is bent inside the virtual inner corner wall surface in the cross section along the passage axis O of the pipe joint 1. Is.
For example, as in the modified example shown in FIG. 3A, the inner corner wall surface 31a is flat extending in an inclined direction with respect to each of the passage axis of the first passage 10d and the passage axis of the second passage 10e. It may consist of faces.
Alternatively, as in the other modification shown in FIG. 3B, the inner corner wall surface 31a may be formed of a recessed surface that is convexly recessed inward by bending.
Further, as long as the insert member 30 has at least the inner corner wall surface 31a, the configuration of other parts may be arbitrary, for example, there is no one of the first cylinder portion 32 and the second cylinder portion 33. You may.
In addition, in FIG. 3A and FIG. 3B, the outer member 40 and the cap 41 are not shown.

From the viewpoint of reducing pressure loss and ease of manufacture, the inner corner wall surface 31a is the first tangent line L1 in the cross section along the passage axis O of the pipe joint 1 as in the examples shown in FIGS. 1 and 3. It is preferable not to have a portion bent outside the virtual inner corner wall surface composed of the second tangent line L2 and the second tangent line L2.

The above-mentioned thing about the pipe joint of this example also applies to other hollow molded products (for example, pipes) having a bent portion of the passage axis in the passage connecting the first passage opening and the second passage opening. The same is true.

[Manufacturing method of hollow molded products]
Next, an embodiment of the method for producing a hollow molded product of the present invention will be described with reference to FIGS. 4 to 8. The method for producing a hollow molded product of the present invention is the method for producing the hollow molded product of the present invention described above. Hereinafter, an example of manufacturing the pipe joint 1 having the configuration described with reference to FIGS. 1 and 2 will be described. The method for manufacturing a pipe joint of this example includes an insert member forming step, a main body member forming step, and an outer member forming step. Hereinafter, each step will be described in order.

(Insert member forming process)
In the insert member forming step, the insert member 30 is formed. As a method for forming the insert member 30, injection molding is preferable from the viewpoint of cost and the like, but other methods may also be used. Here, a method of forming the insert member 30 by injection molding will be described with reference to FIGS. 4 to 5.
FIG. 4 is an exploded perspective view showing a main part of the insert member molding die 100 for forming the insert member 30 by injection molding. FIG. 5 is a perspective view showing a main part of the insert member molding die 100 of FIG. 4 in a closed state. The insert member molding die 100 includes a pair of outer dies 110 and a first inner die member 120 and a second inner die member 130 that are inserted into the cavity 111 internally formed by the pair of outer dies 110. have. Since the configurations of the pair of outer molds 110 are similar to each other, only one outer mold 110 is shown in FIGS. 4 and 5.

The cavity 111 composed of the pair of outer dies 110 includes a columnar cavity 111a forming a molding surface for molding the outer peripheral surface of the first cylinder 32 of the insert member 30 and a second cylinder of the insert member 30. A columnar cavity portion 111b forming a molding surface for molding the outer peripheral surface of the portion 33, and a cavity portion 111c forming a molding surface for molding the inner corner wall surface 31a in the connecting wall 31 of the insert member 30. have. The cavity portion 111a for the first tubular portion 32 and the cavity portion 111c for the connecting wall 31 are connected to a concave portion 112 adjacent to the cylindrical portion formed by the cavity portion 111a for the first tubular portion 32 in the axial direction. The end surface of the recess 112 opposite to the side connected to the cavity 111a for the first cylinder 32 and the cavity 111c for the connecting wall 31 is open to the outside of the outer mold 110. A concave portion 113 formed by the cavity portion 111b for the second tubular portion 33 and adjacent to the cylindrical portion in the axial direction is connected to the cavity portion 111b for the second tubular portion 33. The end face of the recess 113 opposite to the side connected to the cavity 111b for the second cylinder 33 is open to the outside of the outer mold 110.

The first inner mold member 120 is connected to the inner mold portion 121, which is housed in the cavity portion 111a for the first cylinder portion 32 and has a molding surface for molding the inner peripheral surface of the first cylinder portion 32. The inner mold portion 122, which is housed in the cavity portion 111c for the wall 31 and has a molding surface for molding the inner corner wall surface 31a of the connecting wall 31, and the mold block portion 123 that is fitted into the recess 112 without a gap. , And these are integrally configured.

The second inner mold member 130 is housed in the cavity portion 111b for the second cylinder portion 33, and has a molding surface for molding the inner peripheral surface of the second cylinder portion 33, and a recessed portion. It has a mold block portion 132 that is fitted into 113 without a gap, and these are integrally configured.

When the insert member 30 is injection-molded using the insert member molding die 100 configured in this way, first, as shown in FIG. 4, the first die is directed toward the inside of the cavity 111 of the pair of outer dies 110. The inner mold member 120 and the second inner mold member 130 are inserted. At this time, the mold block portions 123 and 132 are fitted into the recesses 112 and 113, respectively, so that the inner mold portions 121, 122 and 131 are positioned at predetermined positions in the cavity portions 111a, 111c and 111b, respectively.
In parallel with or after this, the pair of outer molds 110 are closed. The state at this time is as shown in FIG.
Next, the molten resin, which is the material of the insert member 30, is injected into the cavity 111. After the injected molten resin is cooled and solidified, the first inner mold member 120 and the second inner mold member 130 are pulled out from the molded insert member 30, and the pair of outer molds 110 are opened to form the insert member 30. Remove from cavity 111. As a result, the insert member 30 is obtained.

The insert member 30 formed in this example has an opening portion 34 at a position facing the inner corner wall surface 31a of the connecting wall 31, as described above with reference to FIG. 2B. Due to the presence of the open portion 34, when the insert member 30 is injection-molded as described above, the insert member 30 after molding the first inner mold member 120 having a molding surface for molding the inner corner wall surface 31a. It can be easily pulled out from. In this case, as shown in FIG. 1, the bent outer wall surface of the bent portion 10c of the pipe joint 1 is not formed by the insert member 30, but is formed by the outer corner wall surface 21 of the main body member 20.

(Main body member forming process)
In the main body member forming step, the main body member 20 is integrally molded with the insert member 30 formed in the insert member forming step by injection molding. An example of the main body member forming process will be described with reference to FIGS. 6 to 8.
6 and 7 are exploded perspective views showing the main parts of the outer mold 140 for molding the main body member together with the insert member 30 for integrally molding the main body member 20 with the insert member 30 by injection molding, respectively. , FIG. 7 shows a state after FIG. FIG. 8 is a side view showing a main part of the outer mold 140 for molding the main body member shown in FIG. 6 in a state where the mold is closed together with the insert member 30. The outer mold 140 for molding the main body member includes a pair of outer molds 150, a mold block portion 160 that is in contact with one side surface (lower surface in the figure) of the pair of outer molds 150, and a pair of outer molds 150. It has a third inner mold member 170 and a fourth inner mold member 180 which are inserted into the cavity 150a which is internally formed by the above. Since the configurations of the pair of outer molds 150 are similar to each other, only one outer mold 150 is shown in FIGS. 6 to 8.

The cavity 150a in the pair of outer molds 150 is composed of a molding surface for molding the outer peripheral surface of the main body member 20.

The third inner mold member 170 and the fourth inner mold member 180 are each formed in a pin shape, and as shown in FIG. 8, the positions where their respective tip portions face the inner corner wall surface 31a of the insert member 30. That is, they are housed in the cavity 150a so as to be abutted against each other at the position where the bent portion 10c is formed in the cavity 150a. The outer peripheral surface of the third inner mold member 170 has a molding surface for molding a portion of the main body wall surface (passage wall surface formed by the main body member 20) that constitutes the second passage 10e (see FIG. 1). The outer peripheral surface of the fourth inner mold member 180 has a molding surface for molding a portion of the main body wall surface that constitutes the first passage 10d (see FIG. 1).
A part of the outer corner wall surface 21 of the main body wall surface (passage wall surface formed by the main body member 20) is formed on the tip end portion of the third inner mold member 170 and the tip end portion of the fourth inner mold member 180, respectively. Molding surfaces 170b and 180b are formed.
Further, at the tip of the third inner mold member 170 and the tip of the fourth inner mold member 180, fitting portions 170c and 180c having shapes that can be fitted to each other are formed on the contact surfaces with each other. There is.

The end of the third inner mold member 170 opposite to the tip end thereof is fixed to the mold block portion 160. Further, on the outer peripheral surface of the third inner mold member 170, a recess 170a extending along the extending direction of the third inner mold member 170 is formed only on the tip end side portion of the third inner mold member 170. ..

When the main body member 20 is injection-molded using the main body member molding outer mold 140 configured in this way, first, as shown in FIG. 6, the third inner mold member 170 installed in the mold block portion 160 is used. The second tubular portion 33 of the insert member 30 is fitted into the insert member 30 from the tip end side of the third inner mold member 170. At this time, the ridge 33a of the second cylinder portion 33 of the insert member 30 is engaged with the ridge 170a of the third inner mold member 170, and the ridge 33a reaches the end of the dent 170a. Is moved on the third inner mold member 170. As a result, the insert member 30 is positioned at a predetermined position and posture with respect to the third inner mold member 170.

Next, as shown in FIG. 7, the fourth inner mold member 180 is inserted into the first tubular portion 32 of the insert member 30, and the fitting portion 170c and the fourth inner mold member 180 of the third inner mold member 170 are inserted. The fitting portions 180c of the above are fitted to each other (see also FIG. 8). As a result, the fourth inner mold member 180 is positioned at a predetermined position and posture with respect to the insert member 30 and the third inner mold member 170.

When the pair of outer molds 150 are closed in parallel with or after this, the state as shown in FIG. 8 is obtained. At this time, the insert member 30 is positioned (set) at a predetermined position in the cavity 150a via the third inner mold member 170 and the fourth inner mold member 180. At this time, the third inner mold member 170 and the fourth inner mold member 180 are arranged so as to face each other at a position facing the inner corner wall surface 31a of the insert member 30 (the position where the bent portion 10c of the passage 10 is formed). ..
Next, the molten resin, which is the material of the main body member 20, is injected into the cavity 150a. After the injected molten resin is cooled and solidified, the third inner mold member 170 and the fourth inner mold member 180 are pulled out from the integrally molded product of the molded main body member 20 and the insert member 30, and a pair of outer molds are used. The 150 is opened and the integrally molded product is taken out from the cavity 150a. As a result, an integrally molded product of the main body member 20 and the insert member 30 can be obtained.
At this time, the main body wall surface (passage wall surface formed by the main body member 20) is not covered by the insert member 30 of the outer surfaces of the third inner mold member 170 and the fourth inner mold member 180 in a state of being abutted against each other. It is molded by transferring the shape of the portion.

(Outer member forming process)
In the outer member forming step, the outer member 40 is formed by injection molding on the outer peripheral surface of the integrally molded product of the main body member 20 and the insert member 30 formed in the main body member forming step using an outer mold (not shown).
After forming the outer member 40, the pipe joint 1 is obtained by fitting the cap 41 or the like from the outer peripheral side of the outer member 40.

According to the method for manufacturing a hollow molded product (pipe joint in this example) of the present embodiment, an insert member 30 constituting a wall surface inside a bend at a bent portion 10c is prepared in advance, and a material of a main body member 20 is injected into the insert member 30. Then, both are integrated, and after the main body member 20, the third inner mold member 170 and the fourth inner mold member 180 can be pulled out, so that the inner corner wall surface 31a having an undercut shape, which has not been realized in the past, is formed. This makes it possible to improve the degree of freedom in designing hollow molded products. Further, for example, it becomes possible to manufacture a hollow molded product capable of reducing pressure loss.

In the above-described example, the first cylinder portion 32 and the second cylinder portion 33 of the insert member 30 form the insert member 30 as a main body member via the fourth inner mold member 180 and the third inner mold member 170, respectively. It has a role of positioning in the cavity 150a of the external mold 140. However, the first tubular portion 32 and the second tubular portion 33 may have different configurations as long as they have the positioning function. For example, the peripheral wall is not tubular and the peripheral wall is discontinuous in a part in the circumferential direction. It may be configured in a character shape.
Further, when the insert member 30 can be positioned in the cavity 150a of the outer mold 140 for molding the main body member without going through the third inner mold member 170 and the fourth inner mold member 180, the insert member 30 is the first tubular portion. It is not necessary to have 32 and / or the second cylinder portion 33.
Further, the insert member 30 may be made of metal.

Further, the ridge 33a of the insert member 30 and the dent 170a of the third inner mold member 170 may be composed of the ridge and the ridge, respectively.

The above-mentioned method for manufacturing the pipe joint of this example is a method for manufacturing another hollow molded product having a bent portion in which the passage axis is bent in the passage connecting the first passage port and the second passage port. The same applies to.

The hollow molded article according to the present invention can be used for piping for a fluid such as an arbitrary gas such as cold water, hot water, oil, or a liquid.

1: Pipe fitting (hollow molded product), 10: Passage, 10a: 1st passage, 10b: 2nd passage, 10c: Bent, 10d: 1st passage, 10e: 2nd passage, 20: Main body member , 21: Outer corner wall surface, 30: Insert member, 31: Connecting wall, 31a: Inner corner wall surface, 32: 1st cylinder part, 33: 2nd cylinder part, 33a: Protrusion, 34: Open part, 40: Outside Member, 41: Cap, 50a, 50b: Insertion space, 100: Mold for forming insert member, 110: Outer mold, 111: Cavity, 111a to 111c: Cavity, 112, 113: Recess, 120: First inner mold Members, 121, 122: Inner mold part, 123: Mold block part, 130: Second inner mold member, 131: Inner mold part, 132: Mold block part, 140: Outer mold for molding main body member, 150: Outer mold, 150a: Cavity, 160: Mold block part, 170: Third inner mold member, 170b: Molded surface, 170c: Fitting part, 180: Fourth inner mold member, 180b: Molded surface, 180c: Fitting part, O: Aisle axis

Claims (4)

A hollow molded product having a passage inside which connects the first passage opening and the second passage opening, and having a bent portion where the passage axis is bent in the passage.
A hollow main body member forming a main body wall surface which is a part of the wall surface of the passage,
An insert member that is fixed to the inner peripheral surface of the main body member and constitutes an insert wall surface that is a portion of the wall surface of the passage excluding the main body wall surface.
With
The insert member has an inner corner wall surface that constitutes a bending inner portion at the bent portion of the wall surface of the passage.
In the cross section along the passage axis of the hollow molded product, at least a part of the inner corner wall surface is the first tangent line at the connection point of the passage wall surface continuous from the first passage port with the inner corner wall surface, and the said constituted by a second tangent line at the point of attachment to the inside corner wall of the wall surface of the passage which is continuous from the second passage opening, Ri inside near the bending of the virtual inner corner wall,
The main body member is a hollow molded product composed of one part. The hollow molded product according to claim 1, wherein the main body member has an outer corner wall surface that constitutes a bent outer wall surface at the bent portion of the passage. The method for producing a hollow molded product according to claim 1.
The insert member forming step of forming the insert member and
The insert member is set in the cavity of the outer mold, and a pair of inner molds for molding the wall surface of the main body are arranged so as to face each other at a position facing the inner corner wall surface of the insert member. A main body member forming step in which the main body member is integrally molded with the insert member by injecting molten resin into the inside.
A method for manufacturing a hollow molded product, including. The hollow hollow according to claim 3, wherein in the main body member forming step, the outer corner wall surface forming the bent outer wall surface at the bent portion of the passage is formed on the main body member by the pair of inner molds. Manufacturing method of molded products.

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