JPH07293758A - Pipe joint - Google Patents

Abstract

PURPOSE:To prevent the inner corner parts of a metallic joint body from pressure crevices and cracks caused by high pressure in the injection molding of an inside anticorrosive core without using an outside metal mold. CONSTITUTION:In a pipe joint provided therein with a metallic joint body 1 and an anticorrosive core 2 formed integrally therein by the injection molding injection mold for fusion plastic, the joint body 1 is formed in the inside corner parts 30 with uneven wall uneven thickness parts 5 having the wall thickness increased larger than that of the other parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint having a corrosion resistant portion made of plastic--corrosion resistant core--inside thereof.

[0002]

2. Description of the Related Art The applicant of the present application has already disclosed, in Japanese Patent Application No. 3-37801 (Japanese Utility Model Application No. 4-115627), a plastic anticorrosion part (also referred to as "anticorrosion core" in the present invention) inside a metal joint body. ) Has been proposed. That is, the figure
A joint molding device 21 as shown in FIG.

In the figure, 22 is a metal joint body, and 23 is a plastic anticorrosion part, which is shown in a state during injection molding. The joint body 22 is a cheese mold having an opening 24 on three sides, and the opening 24 is formed with a female screw portion 24a. The molding device includes a cylindrical screw core 25 screwed into the female screw portion 24a of the joint body 22 and slide core pins 26a, 26b, 26c that can be inserted therein.

These three slide core pins 26a, 26b,
26c is butted and molten plastic (dotted points are shown) is injected through the spool hole 27, liner 28 and discharge gate 29 to make a plastic corrosion-resistant portion (corrosion-resistant core).
Form 23.

[0005]

By the way, in the molding apparatus described with reference to FIG. 17, the outer mold for surrounding the joint body 22--
-Since the upper and lower molds are omitted, the injection pressure of the molten plastic described above --- for example, 200kg / cm ²
The pressure that reaches the pressure acts on the inner surface of the joint body 22.

[0006] In a general water pipe fitting, at most 20 kg /
A pressure strength of cm ² is sufficient, and therefore, when a large injection pressure is applied by the molding device described above, a crack is generated in the inner corner portion 30 of the joint body 22 as shown in FIG. That is, a crack is generated at the position indicated by a cross in FIG. It is considered that the cause is that the tensile stress due to the injection pressure is concentrated on the inner corner portion 30. The present invention aims to prevent such cracking (breakage) of the inner corner portion 30.

[0007]

Therefore, the present invention provides a pipe joint comprising a metal joint body and an anticorrosion core integrally formed therein by injection molding of molten plastic. An uneven thickness portion having a wall thickness larger than the wall thickness of other portions was formed at the inner corner of the joint body.

Further, the thickness of the inner corner portion is increased inward to form an uneven thickness portion. Therefore, the cross-sectional shape of the uneven thickness portion of the inner corner is a crescent shape, or in the cross-section of the inner corner of the joint body, the center of the inner hole is the outer surface forming circle. The eccentric portion is formed so as to be eccentric with respect to the center to increase the thickness of the inner corner portion inward. Alternatively, the wall thickness of the inner corner portion is increased outward to form an uneven thickness portion.

[0009] Then, the whole is made into a cheese mold and the inner corner is divided into two.
The shape is such that it has one piece or an inner corner portion as an elbow shape.

Furthermore, the present invention provides a pipe joint comprising a metal joint body and a corrosion-resistant core integrally formed in the interior thereof by injection molding of molten plastic, in the inner corner portion of the joint body. A partially thickened reinforcing portion was formed on the wall except for.

Further, the increased-thickness reinforcing portion has a U shape and is arranged so as to open toward the inner corner. Further, the increased-thickness reinforcing portion is formed in a protruding ridge shape on the outer surface of the joint body. Alternatively, the increased-thickness reinforcing portion is formed in a protruding ridge shape on the inner surface of the joint body.

Further, the whole body is provided with a cheese type joint body, and the thickened reinforcing portions are formed on both side surfaces of the joint body outer surface. Alternatively, the entire body is provided with an elbow type joint body, and the thickened reinforcing portions are formed on both side surfaces of the joint body outer surface.

A pipe joint comprising a metal joint body having two to three openings and a corrosion-resistant core integrally formed therein by injection molding of molten plastic, wherein The joint body is composed of a substantially spherical shell in the middle and a short cylindrical body radially protruding from the substantially spherical shell to form the opening. The substantially spherical shell has a uniform thickness as a whole.

[0014]

[Operation] When molten plastic is injection-molded to form a corrosion-resistant core (see Fig. 17), high pressure acts on the inner surface of the joint body, causing the joint body to elastically deform in the radial direction and stressing the inner corners. Although concentration occurs, since the portion is thickened (in claims 1 to 5), internal stress is reduced and permanent deformation or damage can be prevented.

The wall thickness of the inner corner is increased inward (claim 2)
4), the external shape is the same as the conventional one. Further, if the cross-sectional shape of the uneven thickness portion having the thickness increased inward (as in claim 3) is crescent-shaped, effective reinforcement can be realized.

When the wall thickness of the inner corner portion is increased inward by eccentricity (as in claim 4), the stress distribution becomes more gentle and the stress can be dispersed.

On the contrary, when the wall thickness is increased outward (as in the fifth aspect), there is an advantage that the internal resistance of the flow path does not decrease.

When a molten plastic is injection-molded to form a corrosion-resistant core (see FIG. 17), a high pressure acts on the inner surface of the joint body to elastically deform the joint body in the radial direction, so that the joint body is relatively rigid. Although stress tends to concentrate on the existing inner corner, the rigidity of the wall other than the inner corner is increased by the thickening reinforcement portion formed on the wall excluding the inner corner (in claims 8 to 13). The stress concentration can be relaxed.

If the thickening reinforcement portion is U-shaped and is arranged so as to open toward the inner corner portion (as in claim 9), it is the lightest overall weight and can be moved to the inner corner portion. The stress concentration can be prevented (relaxed).

The same effect can be obtained by forming the thickened reinforcing portions on both side surfaces of the outer surface of the joint body (as in claim 12).

Further, by making the joint body have a substantially spherical shell in the middle (as in claim 14), the stress is dispersed and is not concentrated in the inner corner. This makes it possible to prevent damage (cracks and stress cracks) in the inner corners.
Here, by making the substantially spherical shell body have a uniform thickness as a whole (like claim 15), it is possible to further disperse the stress and reduce the weight.

[0022]

The present invention will be described in detail below with reference to the drawings illustrating the embodiments.

In FIG. 1, (a) shows a cheese type pipe joint as a whole, (b) shows an elbow type pipe joint, and two inner corners 30 are provided at (a) and at (b). Equipped with one. Reference numeral 1 is a metal joint body made of cast iron or the like, and 2 is a corrosion-resistant core (also referred to as "plastic corrosion-resistant portion") integrally formed therein by injection molding of molten plastic.

A female threaded portion 4 is formed on the open end 3 of the joint body 1.
Is formed, and the cylindrical outer end 2a of the anticorrosion core 2 is disposed through the female screw portion 4 and a predetermined cylindrical gap, and the end of the anticorrosion pipe (not shown) is placed in the cylindrical gap. Is inserted.

As is apparent from FIG. 1, the inner wall portion 30 of the joint body 1 is formed with the uneven thickness portion 5 which is thicker than the other portions. Specifically, A-A in FIG.
As shown in FIGS. 2 and 3 showing the cross section and the BB cross section, respectively, the wall thickness of the inner corner portion 30 is increased inward to form the uneven thickness portion 5 having a crescent-shaped cross section. . Therefore, the string 6 on the inner surface
A crescent-shaped uneven thickness portion 5 is formed. It should be noted that the string 6 may be slightly curved (not shown).

On the other hand, in the case of the elbow, by making the CC cross section of (b) of FIG. 1 as shown in FIG. It is formed in the inner corner portion 30.

Next, FIG. 4 and FIG. 5 respectively show the AA cross section and the BB cross section of FIG. 1A, which are cross sections that cross the inner corner portion 30 of the joint body 1. , The center O ₇ of the internal hole ₇
Is eccentric with respect to the center O ₈ of the outer peripheral surface forming circle 8 to form the uneven thickness portion 5 in which the thickness of the inner corner portion 30 is increased inward.

By the way, in the case of FIG. 4, since the inner corner portion 30 is a cross section that appears at one place, the above description is sufficient.
However, in the case of FIG. 5 (showing the BB cross section of (a) of FIG. 1), two inner corners 30 are provided on the left and right,
Two circles having two eccentric centers O ₇ and O ₇ as circle centers are drawn to have a cross-sectional shape in which the increased thickness portion is prioritized so that the uneven thickness portions 5 and 5 are formed in a pair on the left and right. In other words, in FIG. 5, the outer circle is a perfect circle, but the inner hole 7 is a substantially ellipse.

In the case of an elbow type pipe joint, the one shown in FIG.
The C-C cross section of the above may be formed as shown in FIG. 4 by decentering the circle centers O ₇ and O ₈ as described above.

Further, instead of FIGS. 2 and 3 (or FIGS. 4 and 5), as shown in FIGS. 6 and 7, the thickness of the inner corner portion 30 is set in the outward direction, that is, the outer surface side. It is also desirable to increase the thickness to − to form the uneven thickness portion 5. That is, the cross-sectional shape of the internal flow path is circular, and the shape of the internal anticorrosion core 2 and the flow path cross-sectional area can be the same as conventional.

As shown by the chain double-dashed line in FIG. 1A, the protrusion 9 may be formed on the inner surface of the hole of the inner corner 30.

Next, another embodiment is shown in FIG. That is, the whole is a cheese-type metal pipe joint body 1, and inside thereof has a corrosion-resistant core 2 integrally formed by injection molding of molten plastic (not shown in the figure).

On the wall portion of the joint body 1 excluding the inner corner portion 30, a U-shaped thickening reinforcing portion 11 is formed. That is, the thickened reinforcing portion 11 is formed by integrally increasing the thickness in a U shape from the opposite side surface farthest from the inner corners 30, 30 of the cheese type joint body 1 to both side surfaces, and increasing the U shape. The meat reinforcing portion 11 is open toward the inner corner portion 30. Moreover, the outer surface of the joint body
12 is formed in the shape of a ridge.

In another cheese-type embodiment shown in the sectional side view of FIG. 9 and the sectional plan view of FIG. 10, the thickening reinforcement portion 11 is formed on the inner surface 13 of the joint body in the shape of a protrusion. (This has the advantage that the outer surface shape does not change from the conventional one.)

In FIGS. 9 and 10, the anticorrosion core 2 is used.
Are formed inside the joint body 1, and a female screw portion 4 is formed in the opening 3 of the joint body 1 through a predetermined cylindrical gap with the female screw portion 4. The cylindrical outer end 2a of the corrosion-resistant core 2 is disposed, and the end of the corrosion-resistant pipe (not shown) is inserted into this cylindrical gap, which is the same as in the previously described embodiments.

Next, in still another embodiment shown in the perspective view of FIG. 11, the sectional side view of FIG. 12 and the sectional plan view of FIG. 13, the outer surface 12 of the whole cheese-type metal joint body 1 is shown. On both sides of
Kamaboko-shaped (bridge-shaped) thickening reinforcements (11, 11) are formed.

Although it may be preferable to increase the thickness of the inner surface 13 of the joint body to form the increased-thickness reinforcing portion, the illustration is omitted.

Next, in the modified example shown in FIG. 14 (a), a case where the cheese type (see FIG. 8) is an elbow type is shown, and the thickening reinforcing portion 11 is U-shaped It is arranged so as to face the corner 30 and open. Of course, this thickening reinforcement part 11
It is also desirable (not shown) to integrally form the protrusion on the inner surface (instead of forming the protrusion on the outer surface 12 as shown in FIG. 14).

Further, in the modification shown in FIG. 14B,
The whole has a joint body 1 of the elbow type, and the thickened reinforcing portions 11, 11 are formed on both side surfaces of the joint body outer surface 12. It should be noted that this may be formed in a protruding ridge shape on the inner surface of the joint body (not shown).

Further, in another embodiment shown in FIG. 15, 3
The metal joint body 1 having the individual openings 3 ... is formed from the intermediate spherical shell 14 (having a uniform wall thickness) and the spherical shell 14 to form the opening 3 (about 90 ° each). (With a central angle of), the short cylindrical bodies 15 ...

Similar to the above-described embodiment, the corrosion-resistant core 2 is provided inside, and the female screw portions 4 ... Are formed in the openings 3 of the three short cylindrical bodies 15 of the joint body 1. Is.

In the case of an elbow type pipe fitting, approximately 90 °
Although the two short cylindrical bodies 15 and 15 have a central angle of radiating from the substantially spherical shell 14 provided in the middle, they are not shown in the drawing.

In this way, the inner corner 30 bulges outward in a convex shape to reduce the concentration of stress on the inner corner 30, and the spherical shell 14 has a large internal pressure even if it is mechanically thin. It is possible to withstand.

[0044]

The present invention has the following significant effects with the above-mentioned configuration.

Corrosion-proof core 2 (according to claims 1 to 7)
For injection molding of molten plastic to mold
(In the manufacturing method that does not use the outer mold as shown in FIG. 17,) a large tensile stress is generated on the wall surface portion of the joint body 1 and the stress is concentrated on the inner corner portion 30. In the invention, since the uneven thickness portion 5 having the increased thickness of the inner corner portion 30 is provided, the stress value of the inner corner portion 30 can be reduced, and the inner corner portion 30 can be prevented from being damaged such as pressure cracks or cracks. It can be prevented. Moreover, the weight increase is small.

It is preferable (according to claim 2) that the appearance does not (almost) change from the conventional one.

The stress is sufficiently dispersed (according to claim 3).

Dispersion of stress is made smoother (according to claim 4).

(According to claim 5) The resistance as an internal flow path does not decrease, and the shape of the anticorrosion core 2 and the like can be the same as before.

(In accordance with claims 8 to 13) When a high pressure is applied from the inside during injection molding, the thickened reinforcement portion 11 improves rigidity, suppresses elastic deformation, and concentrates stress on the inner corner portion 30. This can be effectively prevented. As a result, the conventional stress value in the inner corner portion 30 can be reduced, and damage such as pressure cracks or cracks in the inner corner portion 30 can be prevented. Moreover, the weight increase is small.

The U-shaped thickening reinforcement portion 11 (according to claim 9) is effective in preventing stress concentration in the inner corner portion 30, and a lightweight pipe joint is obtained.

Outer surface 12 of the joint body (according to claim 12)
The structure in which the thickening reinforcement parts 11, 11 are formed on both sides of the
The effect of preventing stress concentration of 30 is great, and the weight increase is small.

(According to the fourteenth aspect) The substantially spherical shell 14 has an extremely uniform stress distribution when it is subjected to a high pressure, which is advantageous in terms of dynamics and can effectively prevent cracks and the like. Particularly (according to claim 15), if the substantially spherical shell 14 has a uniform thickness, the effect thereof can be increased and the weight can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA or CC of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along line AA or CC of FIG. 1 showing another embodiment.

5 is a sectional view taken along line BB of FIG. 1 showing another embodiment.

6 is a sectional view taken along line AA or CC of FIG. 1 showing another embodiment.

FIG. 7 is a sectional view taken along line BB in FIG. 1 showing another embodiment.

FIG. 8 is a perspective view of yet another embodiment of the present invention.

FIG. 9 is a sectional side view of yet another embodiment of the present invention.

FIG. 10 is a sectional plan view thereof.

FIG. 11 is a perspective view of another embodiment.

FIG. 12 is a sectional side view thereof.

FIG. 13 is a sectional plan view thereof.

FIG. 14 is a perspective view showing a modified example.

FIG. 15 is a cross-sectional side view of yet another embodiment.

FIG. 16 is an explanatory diagram showing a conventional problem.

FIG. 17 is a cross-sectional view illustrating an example of an injection molding method.

[Explanation of symbols]

1 Joint body 2 Corrosion-proof core 3 Opening 5 Uneven thickness part 11 Thickening reinforcement part 12 Outer surface 13 Inner surface 14 Approximate spherical shell 15 Short cylindrical body 30 Inner corner O ₇ center O ₈ center

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Shigeo Ueda 75 Nojiri, Ritto-cho, Kurita-gun, Shiga Prefecture Sekisui Chemical Co., Ltd.

Claims (15)

[Claims] 1. A metal joint body 1 and an anticorrosion core 2 integrally formed therein by injection molding of molten plastic.
In a pipe joint having and, the inner corner portion 30 of the joint body 1 is
A pipe joint characterized in that an uneven thickness portion 5 having a wall thickness greater than that of other portions is formed in the pipe joint. 2. The pipe joint according to claim 1, wherein the thickness of the inner corner portion 30 is increased inward to form the uneven thickness portion 5. 3. The pipe joint according to claim 2, wherein the cross-sectional shape of the uneven thickness portion 5 of the inner corner portion 30 is a crescent shape. 4. In the cross section of the inner corner portion 30 of the joint body 1,
The center O ₇ inside the hole 7 by eccentric to the center O ₈ of the outer peripheral surface forming a circle 8, claim that constitute the uneven thickness portion 5 having an increased wall thickness of the inner corner portion 30 inwardly The pipe joint according to 1. 5. The pipe joint according to claim 1, wherein the thickness of the inner corner portion 30 is increased outward to form the uneven thickness portion 5. 6. The pipe joint according to claim 1, 2, 3, 4, or 5, which is a cheese type as a whole and has two inner corners. 7. The pipe joint according to claim 1, 2, 3, 4, or 5, which is of elbow type as a whole and has one inner corner portion. 8. A metal joint body 1 and an anticorrosion core 2 integrally formed therein by injection molding of molten plastic.
In a pipe joint having and, the inner corner portion 30 of the joint body 1 is
A pipe joint characterized in that a partially thickened reinforcing portion 11 is formed on the wall portion except for. 9. The pipe joint according to claim 8, wherein the thickening reinforcement portion 11 is U-shaped and is arranged so as to open toward the inner corner portion 30. 10. The pipe joint according to claim 8, wherein the increased-thickness reinforcing portion 11 is formed on the outer surface 12 of the joint body in a protruding shape. 11. The pipe joint according to claim 8, wherein the increased-thickness reinforcing portion 11 is formed on the inner surface 13 of the joint body in a protruding shape. 12. The pipe joint according to claim 8, wherein the whole is provided with a cheese-type joint body 1, and the thickened reinforcing portions 11, 11 are formed on both side surfaces of the joint body outer surface 12. 13. The pipe joint according to claim 8, further comprising an elbow type joint body 1 as a whole, and thickening reinforcement portions 11, 11 formed on both side surfaces of the joint body outer surface 12. 14. A pipe joint comprising a metal joint body 1 having two or three openings 3 and a corrosion-resistant core 2 integrally formed therein by injection molding of molten plastic. The joint body 1 is composed of a substantially spherical shell 14 in the middle and a short cylindrical body 15 radially protruding from the substantially spherical shell 14 to form the opening 3. A characteristic pipe joint. 15. The pipe joint according to claim 14, wherein the substantially spherical shell 14 has a uniform thickness throughout.