JP7608815B2 - Composite Pipe - Google Patents

Description

The present invention relates to a composite pipe.

2. Description of the Related Art Conventionally, there is a composite pipe that includes a pipe body and a corrugated pipe that covers the outer periphery of the pipe body (see, for example, Patent Document 1).
The corrugated pipe is bellows-shaped with peaks and valleys alternately provided in the axial direction.

The tube is made of a resin material such as cross-linked polyethylene.
The corrugated pipe has a base pipe and a coating layer that coats the outer circumferential surface of the base pipe. The base pipe is made of a resin material such as closed-cell foamed polyethylene. The coating layer is made of a resin material such as polyethylene.

The tube body and the corrugated pipe are formed separately. The composite pipe is then formed by inserting the tube body through the corrugated pipe.

JP 2017-26129 A

When a composite pipe is used for water piping, the pressure inside the pipe can change suddenly when the tap is turned off. When this happens, the impact force acting on the pipe causes it to collide with the corrugated pipe, generating noise.

To address this issue, it is possible to reduce the inner diameter of the valleys of the corrugated pipe and the gap between the pipe body and the corrugated pipe, thereby preventing collisions between the pipe body and the corrugated pipe. However, in this case, when inserting the pipe body into the corrugated pipe, the two are more likely to interfere with each other, which reduces workability.

The composite pipe for solving the above problem comprises a pipe body and a corrugated pipe covering the outer periphery of the pipe body, the corrugated pipe being bellows-shaped with peaks and valleys having an outer diameter smaller than the outer diameter of the peaks arranged alternately in the axial direction of the corrugated pipe, and having a plurality of protrusions protruding radially inward of the corrugated pipe, the plurality of protrusions being arranged at intervals from one another in the circumferential direction of the corrugated pipe.

According to this configuration, the gap between the corrugated tube and the tube body is partially reduced in the circumferential direction by the multiple protrusions protruding from the corrugated tube. This restricts the relative displacement of the tube body with respect to the corrugated tube. Therefore, when an impact force acts on the tube body due to a sudden change in pressure of the fluid flowing inside the tube body, it is possible to suppress a collision between the tube body and the corrugated tube. This makes it possible to suppress the generation of noise caused by a collision between the tube body and the corrugated tube.

On the other hand, with the above configuration, for example, the gap between the valley portion and the pipe body is reduced over the entire circumference of the corrugated pipe by reducing the inner diameter of the valley portion, so that when the pipe body is inserted into the corrugated pipe, there is less interference between the two. This makes it easier to insert the pipe body into the corrugated pipe.

In the above-mentioned compound pipe, it is preferable that the root portion has an inner diameter smaller than an inner diameter of the peak portion, and the protrusion is provided on the root portion.
According to this configuration, since the protrusions are provided on the valley portions, the size of the protrusions is smaller than when the protrusions are provided on the peak portions, and therefore it is possible to suppress an increase in the weight of the corrugated pipe due to the provision of the protrusions.

Furthermore, according to the above configuration, the provision of the protrusions can suppress the corrugated tube from becoming less susceptible to bending and deformation.
In the above compound pipe, the projections are preferably tapered.

With this configuration, the tip of the protrusion is small, so there is less interference between the corrugated pipe and the tube when inserting the pipe. This makes it easier to insert the tube into the corrugated pipe.

In addition, a composite pipe for solving the above problem includes a pipe body and a corrugated pipe covering the outer periphery of the pipe body, the corrugated pipe is bellows-shaped in which peaks and valleys having an outer diameter smaller than the outer diameter of the peaks are alternately arranged in the axial direction of the corrugated pipe, the valleys have a first valley portion and a second valley portion that is arranged at a different position in the axial direction from the first valley portion, and it is preferable that the first valley portion has a first inner diameter and the second valley portion has a second inner diameter larger than the first inner diameter.

According to this configuration, the gap between the corrugated pipe and the pipe body is smaller in the first valley portion of the corrugated pipe than in the second valley portion. This restricts the relative displacement of the pipe body with respect to the corrugated pipe compared to when all valley portions are formed by the second valley portions. Therefore, when an impact force acts on the pipe body due to a sudden change in pressure of the fluid flowing inside the pipe body, it is possible to suppress a collision between the pipe body and the corrugated pipe. This makes it possible to suppress the generation of noise caused by a collision between the pipe body and the corrugated pipe.

On the other hand, with the above configuration, when inserting the pipe body into the corrugated pipe, there is less interference between them compared to when, for example, all of the valleys are configured as first valleys, thereby reducing the gap between all of the valleys and the pipe body. This makes it easier to insert the pipe body into the corrugated pipe.

In the above-mentioned compound pipe, it is preferable that a plurality of the second valley portions are provided between two of the first valley portions adjacent to each other in the axial direction.
With this configuration, compared to a case where the first valley portions and the second valley portions are alternately provided in the axial direction, the first valley portions and the second valley portions are less likely to interfere with each other when inserting the pipe body into the corrugated pipe, making it easier to insert the pipe body into the corrugated pipe.

This invention can suppress the generation of noise caused by the collision between the pipe body and the corrugated pipe, and can easily insert the pipe body into the corrugated pipe.

FIG. 2 is a perspective view of a composite pipe according to the first embodiment. FIG. 2 is a half cross-sectional view taken along line 2-2 of FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2 . FIG. FIG. 5 is an enlarged cross-sectional view taken along line 5-5 in FIG. FIG. 7 is a perspective view of a composite pipe according to a second embodiment. FIG. 8A is a cross-sectional view taken along line 8a-8a in FIG. 7, and FIG. 8B is a cross-sectional view taken along line 8b-8b in FIG.

First Embodiment
Hereinafter, the first embodiment will be described with reference to FIGS.
First, the configuration of the composite pipe 10 will be described.

As shown in FIGS. 1 to 3, a composite pipe 10 includes a pipe body 11 and a corrugated pipe 12 that covers the outer periphery of the pipe body 11 .
The tube body 11 is made of a resin material.

The resin material constituting the tube body 11 may be, for example, polyolefins such as polybutene, polyethylene, cross-linked polyethylene, and polypropylene, as well as vinyl chloride. Only one of the above resin materials may be used, or two or more of them may be used in combination. The resin material constituting the tube body 11 may also contain other additives. The tube body 11 of this embodiment is made of cross-linked polyethylene.

As shown in Figures 1 to 5, the corrugated pipe 12 is bellows-shaped with peaks 21 and valleys 22, each having an outer diameter smaller than the outer diameter of the peaks 21, arranged alternately in the axial direction of the corrugated pipe 12. The inner and outer diameters of the valleys 22 are smaller than the inner diameter of the peaks 21.

As shown in Figures 1 and 3 to 5, the corrugated pipe 12 has multiple (six in this embodiment) protrusions 23 that protrude radially inward of the corrugated pipe 12. The protrusions 23 are provided in the valley portions 22.

As shown in FIG. 3, the multiple protrusions 23 are spaced apart from one another in the circumferential direction of the corrugated pipe 12. The multiple protrusions 23 are spaced apart from one another in the circumferential direction (at 60 degree intervals in this embodiment).

The protrusion 23 is tapered. More specifically, the protrusion 23 has a pair of inclined surfaces 23a that are inclined radially inward as they approach the center of the protrusion 23 in the circumferential direction, and has a V-shaped cross section.

In this embodiment, the protrusions 23 are provided in all the valleys 22 .
The corrugated pipe 12 has a base pipe made of a resin material and a coating layer (both not shown) also made of a resin material and coating the outer circumferential surface of the base pipe. The coating layer is in close contact with the outer circumferential surface of the base pipe.

The resin material constituting the base pipe may be, for example, polyurethane, polystyrene, polyethylene, polypropylene, ethylene propylene diene rubber, or a mixture thereof. The resin material may contain other additives. The base pipe is preferably a foam. The base pipe of this embodiment is made of closed-cell foamed polyethylene.

Examples of resin materials constituting the coating layer include polyolefins such as polybutene, polyethylene, cross-linked polyethylene, and polypropylene, as well as vinyl chloride. Only one of the above resin materials may be used, or two or more of them may be used in combination. The resin material constituting the coating layer may also contain other additives. The coating layer in this embodiment is made of polyethylene.

Next, the effects of this embodiment will be described.
(1) The corrugated tube 12 has a plurality of protrusions 23 that protrude radially inward of the corrugated tube 12. The plurality of protrusions 23 are provided at intervals from one another in the circumferential direction of the corrugated tube 12.

With this configuration, the gap between the corrugated tube 12 and the tube body 11 is partially reduced in the circumferential direction by the multiple protrusions 23 protruding from the corrugated tube 12. This restricts the relative displacement of the tube body 11 with respect to the corrugated tube 12. Therefore, when an impact force acts on the tube body 11 due to a sudden change in pressure of the fluid flowing through the tube body 11, it is possible to suppress a collision between the tube body 11 and the corrugated tube 12. This makes it possible to suppress the generation of noise caused by a collision between the tube body 11 and the corrugated tube 12.

On the other hand, with the above configuration, for example, the inner diameter of the valley portion 22 is reduced to reduce the gap between the valley portion 22 and the tube body 11 over the entire circumferential direction of the corrugated pipe 12, so that the two are less likely to interfere with each other when the tube body 11 is inserted into the corrugated pipe 12. This makes it easier to insert the tube body 11 into the corrugated pipe 12.

Therefore, the generation of noise caused by the collision between the pipe body 11 and the corrugated pipe 12 can be suppressed, and the operation of inserting the pipe body 11 into the corrugated pipe 12 can be easily performed.
(2) Since the protrusions 23 are provided in the valley portions 22, which have an inner diameter smaller than the inner diameter of the peak portions 21, the size of the protrusions 23 is smaller than that of the peak portions 21. Therefore, the weight of the corrugated pipe 12 is prevented from increasing by providing the protrusions 23.

Furthermore, according to the above-described configuration, the provision of the projections 23 can prevent the corrugated tube 12 from becoming less susceptible to bending and deformation.
(3) The protrusions 23 are tapered.

With this configuration, the tip of the protrusion 23 is small, so that the corrugated pipe 12 and the pipe body 11 are less likely to interfere with each other when they are inserted into each other. This makes it easier to insert the pipe body 11 into the corrugated pipe 12.

Second Embodiment
Hereinafter, the second embodiment will be described with reference to FIGS. 6 to 8, focusing on the differences from the first embodiment.

As shown in FIGS. 6 to 8, the valley portion 22 of the corrugated pipe 12 has a first valley portion 22A and a second valley portion 22B that is provided at a position different from the first valley portion 22A in the axial direction.
8(a) and 8(b), the first valley portion 22A has a first inner diameter R1. The second valley portion 22B has a second inner diameter R2 that is larger than the first inner diameter R1 (R1<R2).

As shown in FIG. 7, a plurality of second valley portions 22B are provided between two first valley portions 22A adjacent to each other in the axial direction.
Next, the effects of this embodiment will be described.

(4) The valley portion 22 has a first valley portion 22A and a second valley portion 22B that is provided at a different position in the axial direction from the first valley portion 22A. The first valley portion 22A has a first inner diameter R1. The second valley portion 22B has a second inner diameter R2 that is larger than the first inner diameter R1.

With this configuration, the gap between the corrugated pipe 12 and the pipe body 11 is smaller in the first valley portion 22A of the corrugated pipe 12 than in the second valley portion 22B. This restricts the relative displacement of the pipe body 11 with respect to the corrugated pipe 12, compared to when all valley portions 22 are formed by the second valley portions 22B. Therefore, when an impact force acts on the pipe body 11 due to a sudden change in pressure of the fluid flowing through the pipe body 11, it is possible to suppress a collision between the pipe body 11 and the corrugated pipe 12. This makes it possible to suppress the generation of noise caused by a collision between the pipe body 11 and the corrugated pipe 12.

On the other hand, with the above configuration, when inserting the corrugated pipe 12, the pipe body 11 and the corrugated pipe 12 are less likely to interfere with each other compared to when, for example, all of the valley portions 22 are configured as the first valley portions 22A, thereby reducing the gap between all of the valley portions 22 and the pipe body 11. This makes it easier to insert the pipe body 11 into the corrugated pipe 12.

(5) The second valley portions 22B are provided between two first valley portions 22A that are adjacent to each other in the axial direction.
According to this configuration, compared to a case where the first valley portions 22A and the second valley portions 22B are alternately provided in the axial direction, the first valley portions 22A and the second valley portions 22B are less likely to interfere with each other when the tube body 11 is inserted into the corrugated pipe 12. This makes it easier to insert the tube body 11 into the corrugated pipe 12.

<Example of change>
The above embodiment can be modified as follows, for example. The present embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

In the first embodiment, some of the valleys 22 may not have the protrusions 23 .
In the first embodiment, the number of protrusions 23 provided in one valley portion 22 may be changed as appropriate.

In the first embodiment, the multiple protrusions 23 may be provided at unequal intervals in the circumferential direction.
In the first embodiment, the protrusion 23 does not have to be tapered.

In the first embodiment, the protrusion 23 may be provided on the peak portion 21 .
In the second embodiment, the number of second valley portions 22B provided between two first valley portions 22A adjacent to each other in the axial direction can be changed as appropriate. For example, the first valley portions 22A and the second valley portions 22B may be provided alternately in the axial direction.

In the first and second embodiments, the corrugated pipe 12 may not have a covering layer, that is, may be constituted only by a connecting pipe.
In the first and second embodiments, the base pipe of the corrugated pipe 12 does not have to be made of a foam. For example, the corrugated pipe 12 may be made of a soft resin material.

Reference Signs List 10: Composite pipe 11: Pipe body 12: Corrugated pipe 21: Peak portion 22: Valley portion 22A: First valley portion 22B: Second valley portion 23: Protrusion 23a: Inclined surface

Claims (1)

A tube body;
A corrugated tube covering an outer periphery of the tube body,
the corrugated pipe is bellows-shaped in which peaks and valleys having an outer diameter smaller than the outer diameter of the peaks are alternately provided in an axial direction of the corrugated pipe, and the corrugated pipe has a plurality of protrusions protruding radially inward of the corrugated pipe,
The plurality of protrusions are spaced apart from one another in a circumferential direction of the corrugated pipe,
The root portion has an inner diameter smaller than an inner diameter of the peak portion,
the protrusion is provided only on the inner circumferential surface of the valley portion among the inner circumferential surfaces of the peak portion and the inner circumferential surface of the valley portion,
The protrusion has a V-shaped cross section in the circumferential direction, and has a recess on the radially outer side that is an inverted version of the protrusion on the radially inner side .
Composite pipe.