JP2021160195A - Cylindrical injection molded body - Google Patents

Abstract

To suppress an occurrence of molding defects.SOLUTION: An outer peripheral surface of a peripheral wall part includes a first outer peripheral surface 13 and a second outer peripheral surface 14 provided at a different position in a circumferential direction. The first outer peripheral surface extends outward in a radial direction toward one side in an axial direction, and the second outer peripheral surface extends in the axial direction in a vertical cross-sectional view, or alternatively, it extends inward in the radial direction toward one side in the axial direction. When an inclination angle with respect to a central axis O in a direction extending outward in the radial direction from one side to the other along the axial direction is positive, and the inclination angle with respect to the central axis O in the direction extending inward in the radial direction from one side to the other side is negative, an inclination angle θ1 of a first inner peripheral surface 15 corresponding to the first outer peripheral surface on the inner peripheral surface of the peripheral wall part with respect to the central axis is smaller than an inclination angle θ2 of a second inner peripheral surface 16 corresponding to the second outer peripheral surface on the inner peripheral surface of the peripheral wall part with respect to the central axis.SELECTED DRAWING: Figure 2

Description

The present invention relates to a cylindrical injection molded product.

Conventionally, a tubular injection-molded article having a peripheral wall portion, for example, as shown in Patent Document 1 below, has been known.
In this type of injection molded product, for example, in order to enhance the decorative effect and improve the operability, the outer peripheral surface of the peripheral wall portion is provided with the positions in the circumferential direction different from each other. And a second outer peripheral surface is provided, the first outer peripheral surface extends outward in the radial direction toward one side in the axial direction, and the second outer peripheral surface extends axially or axially in a longitudinal view. It is conceivable to adopt a configuration that extends inward in the radial direction toward one side.

Japanese Unexamined Patent Publication No. 2013-249093

However, in such an injection molded product, the inclination angle of the inner peripheral surface of the peripheral wall portion with respect to the central axis is generally the same over the entire length in the circumferential direction, so that the meat at the portion where the first outer peripheral surface is located is located. The thickness and the wall thickness at the portion where the second outer peripheral surface is located are different from each other, and at the time of injection molding, the cavity portion for molding the first outer peripheral surface and the cavity portion for forming the second outer peripheral surface are melted. Due to the difference in the flow resistance of the resin, there is a possibility that molding defects are likely to occur, for example, weld lines and voids are generated.

The present invention has been made in view of the above-mentioned circumstances, and the outer peripheral surface of the peripheral wall portion extends outward in the radial direction toward one side in the axial direction, and the outer peripheral surface in the vertical cross-sectional view. A tubular injection molded body that can suppress the occurrence of molding defects even if it has a second outer peripheral surface that extends in the axial direction or extends inward in the radial direction toward one side in the axial direction. The purpose is to provide.

The present invention employs the following means to solve the above problems. That is, in the tubular injection molded body of the present invention, the outer peripheral surface of the peripheral wall portion includes a first outer peripheral surface and a second outer peripheral surface provided at different positions in the circumferential direction, and the first outer peripheral surface is The second outer peripheral surface extends outward in the radial direction toward one side in the axial direction along the central axis of the peripheral wall portion, and the second outer peripheral surface extends in the axial direction in a vertical cross-sectional view, or one side in the axial direction. The inclination angle with respect to the central axis in the direction extending inward in the radial direction toward one side in the axial direction and extending inward in the radial direction is positive, and toward one side in the axial direction. When the inclination angle with respect to the central axis in the direction extending outward in the radial direction is negative, the inner peripheral surface of the peripheral wall portion of the first inner peripheral surface corresponding to the first outer peripheral surface. The inclination angle with respect to the central axis is smaller than the inclination angle of the second inner peripheral surface corresponding to the second outer peripheral surface with respect to the central axis on the inner peripheral surface of the peripheral wall portion.

According to the present invention, the outer peripheral surface of the peripheral wall portion extends in the axial direction or one side in the axial direction with the first outer peripheral surface extending outward in the radial direction toward one side in the axial direction. It is provided with a second outer peripheral surface that extends inward in the radial direction toward the direction of.
Therefore, for example, among the inner peripheral surfaces of the peripheral wall portion, the first inner peripheral surface corresponding to the first outer peripheral surface and the second inner peripheral surface corresponding to the second outer peripheral surface are directed to one side in the axial direction, respectively. When the first outer peripheral surface extends inward in the radial direction (the inclination angle is positive) according to the above, the first outer peripheral surface corresponds to the first outer peripheral surface as it goes to one side in the axial direction. A second outer peripheral surface that extends in the direction opposite to the direction in which it extends in the vertical cross-sectional view and corresponds to the second outer peripheral surface as the second outer peripheral surface extends in the axial direction in the vertical cross-sectional view or toward one side in the axial direction. 2 The inner peripheral surface extends in the same direction as the vertical cross-sectional view. As a result, for example, when the inclination angles of the first inner peripheral surface and the second inner peripheral surface with respect to the central axis are the same, the first outer peripheral surface is positioned in the cylindrical injection molded product. The wall thickness of the portion to be formed becomes thicker than the wall thickness of the portion where the second outer peripheral surface is located.
However, since the inclination angle of the first inner peripheral surface with respect to the central axis is smaller than the inclination angle of the second inner peripheral surface with respect to the central axis, the first inner peripheral surface is in the axial direction as compared with the second inner peripheral surface. The second inner peripheral surface is provided so as to stand up and collapse in the radial direction as compared with the first inner peripheral surface, so that the wall thickness of the portion where the first outer peripheral surface is located is suppressed in the tubular injection molded body. On the other hand, it becomes easy to secure the wall thickness of the portion where the second outer peripheral surface is located, and it is possible to suppress the difference in wall thickness between the portion where the first outer peripheral surface and the second outer peripheral surface are located.

On the other hand, for example, when the first inner peripheral surface and the second inner peripheral surface each extend outward in the radial direction toward one side in the axial direction (the inclination angle is negative), the first outer peripheral surface is present. As the surface is directed to one side in the axial direction, the first outer peripheral surface and the corresponding first inner peripheral surface extend in the same direction as the vertical sectional view, and the second outer peripheral surface extends in the vertical sectional view. As it extends in the axial direction or toward one side in the axial direction, the second inner peripheral surface corresponding to the second outer peripheral surface extends in the direction opposite to the direction in which it extends in the vertical cross-sectional view. As a result, for example, when the inclination angles of the first inner peripheral surface and the second inner peripheral surface with respect to the central axis are the same, the first outer peripheral surface is positioned in the cylindrical injection molded product. The wall thickness of the portion to be formed is thinner than the wall thickness of the portion where the second outer peripheral surface is located.
However, since the inclination angle of the first inner peripheral surface with respect to the central axis is smaller than the inclination angle of the second inner peripheral surface with respect to the central axis (the absolute value is larger), the first inner peripheral surface is the first. 2 The second inner peripheral surface is provided so as to be inclined in the radial direction as compared with the inner peripheral surface and the second inner peripheral surface is provided to stand up in the axial direction as compared with the first inner peripheral surface. While suppressing the wall thickness of the portion where the surface is located, it becomes easier to secure the wall thickness of the portion where the first outer peripheral surface is located, and the difference in wall thickness between the first outer peripheral surface and the second outer peripheral surface is located. It can be suppressed.

From the above, regardless of whether the inclination angles of the first inner peripheral surface and the second inner peripheral surface are positive or negative, the cavity portion for forming the first outer peripheral surface and the first outer peripheral surface at the time of injection molding. 2 It is possible to suppress a difference in the flow resistance of the molten resin between the cavity portion for molding the outer peripheral surface and the molten resin, and it becomes possible to smoothly spread the molten resin over the entire area in the cavity during injection molding, thereby preventing molding defects. It can be made less likely to occur.

When the tubular injection molded body has a top wall portion or a bottom wall portion that closes an opening on one side in the axial direction in the peripheral wall portion, the inner peripheral surface of the peripheral wall portion faces one side in the axial direction. If it extends inward in the radial direction according to the above, a draft of the molding die is provided on the inner peripheral surface of the peripheral wall portion, and the tubular injection molded body having the top wall portion or the bottom wall portion. , It is possible to secure the releasability for the molding die.

The first outer peripheral surface and the second outer peripheral surface may be provided alternately along the central axis.

In this case, since the first outer peripheral surface and the second outer peripheral surface are alternately provided along the central axis, for example, the decorative effect can be surely enhanced, and the molten resin is placed in the cavity during injection molding. It can be reliably distributed over the entire area.

The peripheral wall portion has a top wall portion or a bottom wall portion that closes an opening on one side in the axial direction, and the first outer peripheral surface and the second outer peripheral surface sandwich the central axis in the radial direction. They may be separately provided at positions facing each other.

In this case, the first outer peripheral surface and the second outer peripheral surface are separately provided at positions facing each other with the central axis in the radial direction, and the first outer peripheral surface sandwiches the central axis in the radial direction. Since they are not separately provided at positions facing each other, when the tubular injection molded body is demolded, a cavity formed by molding the outer peripheral surface of the peripheral wall portion, the upper surface of the top wall portion, or the lower surface of the bottom wall portion is formed. The molding die to be held can be smoothly moved relative to the injection-molded article on one side in the axial direction without being caught, and the tubular injection-molded article having a top wall portion or a bottom wall portion can be moved. Releasability to the molding die can be ensured.

The sum of the sizes of the second inner peripheral surface along the central axis, which has a top wall portion or a bottom wall portion that closes an opening on one side in the axial direction of the peripheral wall portion, is the first. It may be larger than the sum of the sizes of the inner peripheral surface along the circumference of the central axis.

In this case, for example, when the first inner peripheral surface and the second inner peripheral surface each extend inward in the radial direction toward one side in the axial direction (the inclination angle is positive), and the first case. When the inner peripheral surface and the second inner peripheral surface each extend outward in the radial direction toward one side in the axial direction (the inclination angle is negative), the first inner peripheral surface is in any case. , And the sum of the sizes of the second inner peripheral surface, which is easily separated from the molding die, along the central axis, is along the central axis of the first inner peripheral surface. Since it is larger than the total size, it is possible to ensure the releasability of the tubular injection molded body having the top wall portion or the bottom wall portion with respect to the molding die.

According to the present invention, the outer peripheral surface of the peripheral wall portion extends in the axial direction or one side in the axial direction with the first outer peripheral surface extending outward in the radial direction toward one side in the axial direction. Even if the second outer peripheral surface that extends inward in the radial direction toward the front surface is provided, the occurrence of molding defects can be suppressed.

It is a top view of the cylindrical injection molded article shown as one Embodiment which concerns on this invention. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 shown as an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 shown as a modified example according to the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the cylindrical injection molded body 1 according to the present embodiment has a peripheral wall portion 11 and a top wall portion 12 having an opening on one side of the peripheral wall portion 11 closed. It is formed in a tubular shape.
Hereinafter, the direction along the central axis O of the peripheral wall portion 11 is referred to as an axial direction, the top wall portion 12 side along the axial direction is referred to as an upper side, and the open end side of the peripheral wall portion 11 is referred to as a lower side. Further, when viewed from the axial direction, the direction that intersects the central axis O is referred to as the radial direction, and the direction that orbits around the central axis O is referred to as the circumferential direction.

The gate portion at the time of injection molding is located, for example, at the center portion in the radial direction on the upper surface of the top wall portion 12.
The injection-molded article 1 exhibits a pentagonal shape having five corner portions and five side portions when viewed from the axial direction. When viewed from the axial direction, the five corner portions have a protruding curved shape toward the outside in the radial direction. The injection molded body 1 may have a circular shape, a triangular shape, or the like when viewed from the axial direction.

Here, the outer peripheral surface of the peripheral wall portion 11 extends outward in the radial direction toward one side in the axial direction, and extends inward in the radial direction toward one side in the axial direction. A second outer peripheral surface 14 is provided. The first outer peripheral surface 13 and the second outer peripheral surface 14 are provided at different positions in the circumferential direction. The first outer peripheral surface 13 and the second outer peripheral surface 14 are separately provided at positions facing each other with the central axis O in the radial direction.
The second outer peripheral surface 14 may extend in the axial direction while being straight in the axial direction or curved in the radial direction in a vertical cross-sectional view along the central axis O. Further, the first outer peripheral surface 13 may be separately provided at a position facing each other with the central axis O in the radial direction, and the second outer peripheral surface 14 may be provided at a position facing each other with the central axis O in the radial direction. May be provided separately for each.

In the illustrated example, the first outer peripheral surface 13 is located at the corner portion and extends straight outward in the radial direction as it goes upward. The second outer peripheral surface 14 is located at the central portion in the circumferential direction of the side portion, and extends straight inward in the radial direction as it goes upward. The first outer peripheral surface 13 and the second outer peripheral surface 14 are provided alternately in the circumferential direction.
For example, the first outer peripheral surface 13 may be positioned at the side portion and the second outer peripheral surface 14 may be located at the corner portion. Further, the first outer peripheral surface 13 and the second outer peripheral surface 14 may be curved in the radial direction in a vertical cross-sectional view.

The inner peripheral surface of the peripheral wall portion 11 extends inward in the radial direction as it goes upward. The inner peripheral surface of the peripheral wall portion 11 is upward over the entire length in the circumferential direction, including the first inner peripheral surface 15 corresponding to the first outer peripheral surface 13 and the second inner peripheral surface 16 corresponding to the second outer peripheral surface 14. It extends inward in the radial direction as it goes toward it.
As the second outer peripheral surface 14 goes upward, the second inner peripheral surface 16 extends inward in the same radial direction as the direction in which the second inner peripheral surface 16 extends in the vertical cross-sectional view, and the first outer peripheral surface 13 faces upward. Therefore, the first inner peripheral surface 15 extends outward in the radial direction opposite to the direction in which the first inner peripheral surface 15 extends in the vertical cross-sectional view.

The inclination angle with respect to the central axis O, which extends inward in the radial direction toward the upward direction, is positive (+), and the inclination with respect to the central axis O, which extends outward in the radial direction toward the upward direction. When the angle is negative (−), the inclination angle θ1 of the first inner peripheral surface 15 with respect to the central axis O is smaller than the inclination angle θ2 of the second inner peripheral surface 16 with respect to the central axis O.
In the illustrated example, these inclination angles θ1 and θ2 are positive (+). The inclination angle of the inner peripheral surface of the peripheral wall portion 11 with respect to the central axis O is −5 ° or more. If the inclination angle of the inner peripheral surface of the peripheral wall portion 11 with respect to the central axis O is smaller than −5 °, it may be difficult to release the injection molded body 1 from the molding die formed on the inner peripheral surface of the peripheral wall portion 11. ..

The wall thickness of the peripheral wall portion 11 is the same over the entire length in the circumferential direction at the same position in the axial direction. The outer peripheral surface and the inner peripheral surface of the peripheral wall portion 11 are connected without a step over the entire length in the circumferential direction.
The sum of the sizes of the second inner peripheral surface 16 along the circumferential direction is larger than the sum of the sizes of the first inner peripheral surface 15 along the circumferential direction. In the illustrated example, the size of one second inner peripheral surface 16 along the circumferential direction is larger than the size of one first inner peripheral surface 15 along the circumferential direction.

As described above, according to the tubular injection molded body 1 according to the present embodiment, the outer peripheral surface of the peripheral wall portion 11 is upward with the first outer peripheral surface 13 extending outward in the radial direction as it goes upward. A second outer peripheral surface 14 that extends inward in the radial direction toward the inside is provided, and among the inner peripheral surfaces of the peripheral wall portion 11, the first inner peripheral surface 15 corresponding to the first outer peripheral surface 13 and the second outer peripheral surface are provided. The second inner peripheral surface 16 corresponding to 14 extends inward in the radial direction as it goes upward (the inclination angle is positive).

Therefore, as the first outer peripheral surface 13 goes upward, the first inner peripheral surface 15 extends in the direction opposite to the direction in which the first inner peripheral surface 15 extends in the vertical cross-sectional view, and as the second outer peripheral surface 14 goes upward, the second outer peripheral surface 14 extends. The inner peripheral surface 16 extends in the same direction as the vertical cross-sectional view. As a result, for example, as shown by the alternate long and short dash line in FIG. 2, when the inclination angles of the first inner peripheral surface 15 and the second inner peripheral surface 16 with respect to the central axis O are the same as each other. In the tubular injection molded body 1, the wall thickness of the portion where the first outer peripheral surface 13 is located is thicker than the wall thickness of the portion where the second outer peripheral surface 14 is located.

However, since the inclination angle θ1 of the first inner peripheral surface 15 with respect to the central axis O is smaller than the inclination angle θ2 of the second inner peripheral surface 16 with respect to the central axis O, the first inner peripheral surface 15 is the second inner circumference. The second inner peripheral surface is provided so as to stand up in the axial direction as compared with the surface 16 and to be inclined in the radial direction as compared with the first inner peripheral surface. While suppressing the wall thickness of the portion where the first outer peripheral surface 14 is located, it becomes easier to secure the wall thickness of the portion where the second outer peripheral surface 14 is located, and the wall thickness at each portion where the first outer peripheral surface 13 and the second outer peripheral surface 14 are located. The difference can be suppressed.

From the above, it is possible to prevent a difference in the flow resistance of the molten resin between the cavity portion for molding the first outer peripheral surface 13 and the cavity portion for molding the second outer peripheral surface 14 during injection molding, and during injection molding. The molten resin can be smoothly distributed over the entire area in the cavity, and molding defects can be less likely to occur.

Since the first outer peripheral surface 13 and the second outer peripheral surface 14 are provided alternately in the circumferential direction, for example, the decorative effect can be surely enhanced, and the molten resin can be surely spread over the entire area in the cavity at the time of injection molding. It can be distributed.
Since the inner peripheral surface of the peripheral wall portion 11 extends inward in the radial direction as it goes upward, a draft of the molding die is provided on the inner peripheral surface of the peripheral wall portion 11, and the top wall portion 12 It is possible to secure the mold releasability of the tubular injection molded body 1 having the above shape with respect to the molding die.

The first outer peripheral surface 13 and the second outer peripheral surface 14 are separately provided at positions facing each other with the central axis O sandwiched in the radial direction, and the first outer peripheral surface 13 sandwiches the central axis O in the radial direction. Since they are not separately provided at positions facing each other, a molding die having a cavity formed by molding the outer peripheral surface of the peripheral wall portion 11 and the upper surface of the top wall portion 12 when the tubular injection molded body 1 is removed from the mold. Can be smoothly moved relative to the injection molded body 1 without being caught upward, and the mold releasability of the tubular injection molded body 1 having the top wall portion 12 with respect to the molding die is ensured. Can be done.

Of the first inner peripheral surface 15 and the second inner peripheral surface 16 which extend inward in the radial direction toward the upper side and have a positive (+) inclination angle with respect to the central axis O, the inclination angle is larger and the molding is performed. Since the total size of the second inner peripheral surface 16 that can be easily separated from the mold along the circumferential direction is larger than the total size of the first inner peripheral surface 15 along the circumferential direction, the top wall portion 12 is formed. It is possible to secure the releasability of the tubular injection molded body 1 to be molded.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

As shown in FIG. 3, the first inner peripheral surface 21 and the second inner peripheral surface 22 may extend outward in the radial direction toward the upper side (the inclination angle is negative).
In this case, as the first outer peripheral surface 13 goes upward, the first outer peripheral surface 13 and the first inner peripheral surface 21 corresponding to the first outer peripheral surface 13 extend in the same direction as the extension in the vertical cross-sectional view, and the second outer peripheral surface 14 However, as it goes upward, the second inner peripheral surface 22 corresponding to the second outer peripheral surface 14 extends in the direction opposite to the direction in which the second inner peripheral surface 22 extends in the vertical cross-sectional view. As a result, for example, as shown by the alternate long and short dash line in FIG. 3, when the inclination angles of the first inner peripheral surface 21 and the second inner peripheral surface 22 with respect to the central axis are the same as each other, In the tubular injection molded body 2, the wall thickness of the portion where the first outer peripheral surface 13 is located is thinner than the wall thickness of the portion where the second outer peripheral surface 14 is located.
However, the inclination angle θ3 of the first inner peripheral surface 21 with respect to the central axis O is smaller than the inclination angle θ4 of the second inner peripheral surface 22 with respect to the central axis O (the absolute value is larger). 1 The inner peripheral surface 21 is provided so as to collapse in the radial direction as compared with the second inner peripheral surface 22 and the second inner peripheral surface 22 is provided so as to stand up in the axial direction as compared with the first inner peripheral surface 21. In the shape injection molded body 2, it becomes easier to secure the wall thickness of the portion where the first outer peripheral surface 13 is located while suppressing the wall thickness of the portion where the second outer peripheral surface 14 is located, and the first outer peripheral surface 13 and the second outer peripheral surface 13 and the second. It is possible to suppress the difference in wall thickness at each portion where the outer peripheral surface 14 is located.

From the above, it is possible to prevent a difference in the flow resistance of the molten resin between the cavity portion for molding the first outer peripheral surface 13 and the cavity portion for molding the second outer peripheral surface 14 during injection molding, and during injection molding. The molten resin can be smoothly distributed over the entire area in the cavity, and molding defects can be less likely to occur.

In the injection molded product 2, the total size of the second inner peripheral surface 22 along the circumferential direction may be larger than the total size of the first inner peripheral surface 21 along the circumferential direction. Further, the size of one second inner peripheral surface 22 along the circumferential direction may be larger than the size of one first inner peripheral surface 21 along the circumferential direction.
In this case, of the first inner peripheral surface 21 and the second inner peripheral surface 22 which extend outward in the radial direction toward the upper side and have a negative (-) inclination angle with respect to the central axis O, the inclination angle is The total size of the second inner peripheral surface 22 which is large (small as an absolute value) and easy to be separated from the molding die along the circumferential direction is the size of the first inner peripheral surface 21 along the circumferential direction. Since it is larger than the total, it is possible to ensure the releasability of the tubular injection molded body 2 having the top wall portion 12 with respect to the molding die.

The injection molded bodies 1 and 2 may be formed in a cylindrical shape having both ends open, or may be formed in a bottomed tubular shape having a peripheral wall portion 11 and a bottom wall portion.

The inner peripheral surface of the peripheral wall portion 11 has a first portion (inclination angle is positive) extending inward in the radial direction as it goes upward, and a second portion (inclination angle is positive) that extends outward in the radial direction as it goes upward. Negative) and two or more of the third portions extending in the axial direction may have different positions in the circumferential direction.
In this configuration, the first outer peripheral surface 13 and the second outer peripheral surface 14 may face two or more types of the first portion, the second portion, and the third portion in the radial direction, respectively. Further, when the inner peripheral surface of the peripheral wall portion 11 has the second portion, it is preferable that the inner peripheral surface has the first portion. In this case, it becomes easy to secure the releasability of the injection molded body 1 with respect to the molding die.

The inner peripheral surface of the peripheral wall portion 11 has a first inner peripheral surface 21 extending outward in the radial direction as it goes upward, and inward in the radial direction as it extends axially or upward in a vertical cross-sectional view. It may have a second inner peripheral surface 16 extending toward it. In this configuration, the absolute value of the inclination angle θ3 of the first inner peripheral surface 21 with respect to the central axis O may be larger than the inclination angle θ2 of the second inner peripheral surface 16 with respect to the central axis O.

In addition, it is possible to replace the components in the embodiment with well-known components as appropriate without departing from the spirit of the present invention, and the embodiments and modifications may be combined as appropriate.

1, 2 Cylindrical injection molded body 11 Peripheral wall 13 First outer peripheral surface 14 Second outer peripheral surface 15, 21 First inner peripheral surface 16, 22 Second inner peripheral surface O Center axis θ1, θ2, θ3, θ4 Tilt angle

Claims (4)

The outer peripheral surface of the peripheral wall portion includes a first outer peripheral surface and a second outer peripheral surface provided at different positions in the circumferential direction.
The first outer peripheral surface extends outward in the radial direction toward one side in the axial direction along the central axis of the peripheral wall portion.
The second outer peripheral surface extends in the axial direction in a vertical cross-sectional view, or extends inward in the radial direction toward one side in the axial direction.
The inclination angle with respect to the central axis in the direction extending inward in the radial direction toward one side in the axial direction is set to positive.
When the inclination angle with respect to the central axis in the direction extending outward in the radial direction toward one side in the axial direction is negative.
On the inner peripheral surface of the peripheral wall portion, the inclination angle of the first inner peripheral surface corresponding to the first outer peripheral surface with respect to the central axis is determined.
A cylindrical injection-molded article having an inner peripheral surface of the peripheral wall portion, which is smaller than the inclination angle of the second inner peripheral surface corresponding to the second outer peripheral surface with respect to the central axis. The tubular injection molded product according to claim 1, wherein the first outer peripheral surface and the second outer peripheral surface are alternately provided along the central axis. It has a top wall portion or a bottom wall portion that closes an opening on one side in the axial direction of the peripheral wall portion.
The tubular injection molded product according to claim 1 or 2, wherein the first outer peripheral surface and the second outer peripheral surface are separately provided at positions facing each other with the central axis line interposed therebetween. It has a top wall portion or a bottom wall portion that closes an opening on one side in the axial direction of the peripheral wall portion.
Any one of claims 1 to 3, wherein the sum of the sizes of the second inner peripheral surface along the central axis is larger than the sum of the sizes of the first inner peripheral surface along the central axis. The tubular injection molded body according to the item.

Images