JP2020139580A - Pipe joint - Google Patents

Abstract

To provide a pipe joint which is excellent in vibration resistance.SOLUTION: A tapered face 9a whose diameter becomes large as approaching a female screw member 5 is formed at a face opposing the female screw member 5 of a male screw member 2. A tapered face 8a whose diameter becomes small as approaching the male screw member 2 is formed at a face opposing the male screw member 2 of the female screw member 5. The two tapered faces 8a, 9a are formed so that the two tapered faces 8a, 9a partially contact with each other (upper part in a figure) in a state that a pipe joint 1 is connected, and the tapered faces 8a. 9a do not partially contact with each other (lower part in the figure).SELECTED DRAWING: Figure 1

Description

The present invention relates to a pipe joint, and more particularly to a pipe joint having improved vibration resistance.

As a pipe joint, a male screw member and a female screw member (nut) are well known to be joined by being screwed together (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-10714

In the conventional pipe joint, the number of rotation nuts to be tightened by using a tool (wrench or the like) is specified from the state of being tightened by hand, and loosening of the screw is prevented by performing the tightening according to this specification. However, when used under conditions of large vibrations such as pumps and compressors, the entire pipe joint may be repeatedly vibrated over a long period of time, causing the screws to loosen. Improvement is required.

An object of the present invention is to provide a pipe joint having excellent vibration resistance.

The pipe joint according to the present invention is a pipe joint in which a male screw member and a female screw member are screwed together, and the diameter of the male screw member increases as it approaches the female screw member on the surface of the male screw member facing the female screw member. Along with the formation of the tapered surface, a tapered surface of the female screw member facing the male screw member is formed, and the diameter of the female screw member decreases as it approaches the male screw member. It is characterized in that, in a state where the pipe joint is connected, a part of the tapered surfaces is in contact with each other and a part of the tapered surfaces is not in contact with each other.

In order to prevent a part of the tapered surfaces from contacting each other and a part of the tapered surfaces from contacting each other while the pipe joint is connected, for example, a part of one of the tapered surfaces should be cut off. Alternatively, one of the tapered surfaces may be eccentric. When the tapered surface is eccentric, the tapered surface of the male screw member may be provided so as to be eccentric from the inner peripheral surface of the male screw member, and the tapered surface of the female screw member should be provided so as to be eccentric from the inner peripheral surface of the female screw member. You may.

According to this pipe joint, a force is applied in the radial direction at a portion where the tapered surfaces are in contact with each other, and no force is applied in the radial direction at a portion where the tapered surfaces are not in contact with each other. Therefore, a radial force partially acts between the tapered surfaces, which acts as a force against the loosening of the screw and prevents the loosening of the screw.

In order to obtain this pipe joint, it is necessary to make the male-threaded member and the female-threaded member into different shapes from the conventional ones, but it is not necessary to increase the number of members, and tightening can be performed in the same manner as the conventional ones. Therefore, switching from the existing pipe joint can be easily performed.

The pipe joint may be a two-compression ring type that fixes the pipe by plastically deforming two rings called a front ring and a back ring, and the gasket provides the required sealing property by plastically deforming. It may be what you get.

According to this pipe joint, even when the entire pipe joint is repeatedly vibrated for a long period of time, the sealing property is ensured and the vibration resistance is excellent. Further, since it is not necessary to increase the number of members and tightening can be performed in the same manner as in the conventional case, it is possible to easily switch from the existing pipe joint.

FIG. 1 is a vertical cross-sectional view showing one embodiment of a pipe joint according to the present invention. FIG. 2 is a perspective view schematically showing a main part of an example of a female thread member used in a pipe joint according to the present invention.

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the left side of FIG. 1 is referred to as the front side, and the right side is referred to as the rear side.

FIG. 1 shows a first embodiment of a pipe joint according to the present invention. The pipe joint 1 has a fluid passage 2a, a male screw member 2 into which a pipe is inserted from the rear end side, and a male screw member 2 after the male screw member 2. It includes a front ring 3 and a back ring 4 that are fitted around a pipe (not shown) protruding from the end side, and a female screw member 5 that tightens the front ring 3 and the back ring 4 to fix the pipe to the male screw member 2. ..

This pipe joint 1 is called a two-compression ring type pipe joint, and is provided on the buck ring 4 as the female screw portion 7 of the female screw member 5 is screwed onto the male screw portion 6 of the male screw member 2. The front ring 3 and the back ring 4 are advanced while the tapered surface 4a is recessed into the tapered surface 3a provided on the front ring 3, so that the front ends of the front ring 3 and the back ring 4 are within the radial direction. It is deformed in the direction and bites into the pipe.

FIG. 1 shows a state in which the female screw member 5 is manually tightened to the male screw member 2. In this pipe joint 1, the amount of rotation of the female thread member 5 when the female thread member 5 is manually tightened to the male thread member 2 and then tightened by a tool is defined. By setting this amount of rotation, the female thread member 5 becomes loose. Is prevented, and the pipe and the male screw member 2 are fixed.

In the pipe joint 1 of this embodiment, the female screw member 5 is provided with an extension portion 8 that reaches the tool engagement portion 2b of the male screw member 2, and the extension portion is provided on the rear surface of the tool engagement portion 2b of the male screw member 2. An opposing portion 9 for receiving the front end portion of the 8 is provided.

Then, a tapered surface 9a whose diameter increases as it approaches the female screw member 5 is formed on the surface of the facing portion 9 facing the extension portion 8, and the male screw member 2 is formed on the surface of the extension portion 8 facing the extension portion 9. A tapered surface 8a is formed in which the diameter decreases as the diameter approaches. The angles of the tapered surfaces 8a and 9a may be the same or slightly different from each other.

In the conventional two-compression ring type pipe joint, a space is provided between the front end portion of the female screw member and the tool engaging portion of the male screw member facing the front end portion, and the female screw member and the male screw member interfere with each other. It was made not to be.

On the other hand, in the pipe joint 1 of this embodiment, the tapered surfaces 8a and 9a are formed so that the tapered surfaces 8a and 9a interfere with each other. Specifically, each of the tapered surfaces 8a and 9a is in a state where the female screw member 5 shown in FIG. 1 is manually tightened to the male screw member 2, and the tapered surfaces 8a and 9a are in contact with each other in the upper part but in the lower part. , The gap G is formed between the tapered surface 8a and the tapered surface 9a.

Therefore, when the female screw member 5 is tightened with a tool from the state of FIG. 1, a force is generated between the tapered surfaces 8a and 9a that are in contact with each other, and between the tapered surfaces 8a and 9a where the gap G exists. Since this force is not generated, an obliquely downward force of FIG. 1 acts on the female screw member 5 as a whole.

In this way, according to the pipe joint 1 of this embodiment, the front ring 3 and the back ring 4 are plastically deformed as the female screw member 5 is tightened to fix the pipe, and after tightening, the female screw member 5 vibrates. On the other hand, a radial force for preventing loosening of the screw acts on the pipe joint 1, and a pipe joint 1 having excellent vibration resistance can be obtained. As a result, even when vibration is repeated for a long period of time, defects such as deterioration of sealing property can be prevented.

In order to form the gap G, for example, a part (for example, about 1/4 circumference) is left as it is with reference to a concentric pipe joint having a cross section shown on the upper side of FIG. The tapered surface 8a of the extension portion 8 may be cut off so that the portion of the extension portion 8 has the cross section shown on the lower side of FIG. Instead of the extension portion 8, a part of the facing portion 9 of the male screw member 2 may be cut off. Further, one of the two tapered surfaces 8a and 9a may be eccentric.

When the tapered surface 8a of the extension portion 8 of the female screw member 5 is eccentric, the center of the tapered surface 9a of the facing portion 9 is not eccentric, and the extension portion 8 of the female screw member 5 is the inner peripheral surface 8b in FIG. The center may be aligned with the center of the female threaded portion 5a, and the center of the tapered surface 8a may be eccentric with respect to the center of the inner peripheral surface 8b. As a result, the tapered surfaces 8a and 9a are partially in contact with each other, and on the side 180 degrees away from the contacting portion, a gap G is formed between the tapered surface 8a and the tapered surface 9a. ..

Although FIG. 1 shows a two-compression ring-type pipe joint 1, a two-compression ring-type pipe has a configuration in which loosening is prevented by partially contacting the tapered surfaces 8a and 9a. It is not limited to the joint 1, and can be applied to a pipe joint using a gasket for the seal portion. The pipe joint also includes a pair of pipe joint members, and a male screw portion is formed on either one of the first and second pipe joint members, and both are formed by a female screw member screwed to the male screw portion of the pipe joint member. The pipe joint member may be joined, and the first and second pipe joint members are sleeves in which no male screw portion is formed, and both pipe joints are formed by the male screw member and the female screw member which are separate members. The members may be joined together. Further, the male screw member may be a closing plug having no fluid passage.

As described above, the present invention can be suitably used for pipe joints used under conditions of large vibration such as pumps and compressors. At this time, since it is not necessary to add the number of parts, it is possible to easily switch from the existing pipe joint.

1: Pipe fitting 2: Male thread member 5: Female thread member 8a: Tapered surface 9a: Tapered surface

Claims (4)

In a pipe joint in which a male thread member and a female thread member are screwed together to be connected.
A tapered surface whose diameter increases as it approaches the female screw member is formed on the surface of the male screw member facing the female screw member, and the male screw member is formed on the surface of the female screw member facing the female screw member. A tapered surface whose diameter decreases as it approaches is formed, and the two tapered surfaces are in contact with each other in a state where the pipe joint is connected, and a part of the tapered surfaces is in contact with each other. A pipe fitting characterized by being formed so as not to come into contact with each other. The pipe joint according to claim 1, wherein at least one of the two tapered surfaces is a tapered surface with a part cut off. The pipe joint according to claim 1, wherein the tapered surface of the male screw member is provided so as to be eccentric from the inner peripheral surface of the male screw member. The pipe joint according to claim 1, wherein the tapered surface of the female screw member is provided so as to be eccentric from the inner peripheral surface of the female screw member.

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