JP2019178689A - Pipe joint - Google Patents

Abstract

To provide a pipe joint excellent even in vibration resistance without deteriorating sealability due to temperature change.SOLUTION: A pipe joint comprises a pair of joint members in at least one of which a fluid passage is formed, and a female screw member 7 through which any one of the joint members 3 is inserted, wherein the pair of joint members are coupled to each other by a male screw 4a formed on the other joint member or the male screw 4a of a male screw member 4 attached to the other joint member 2 and a female screw 4a of a female screw member 4. One joint member 3 is a cylindrical sleeve 3 having an outward flange 8. A female screw member 7 comprises, on its inner peripheral surface, a female screw 7a and an inward flange 9 facing an outward flange 8 of the sleeve 3, and is provided with an energization member 12 into which the sleeve 3 is fitted and which between the opposing surfaces of the outward flange 8 and inward flange 9, energizes both flanges outward in an axial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pipe joint, and more particularly to a pipe joint that prevents a decrease in sealing performance when temperature changes.

  The pipe joint includes, for example, a pair of joint members having fluid passages communicating with each other and an annular gasket interposed between the butted end surfaces of the pair of joint members. There is known one in which a pair of joint members are coupled to each other by a male screw member provided in the joint member and a female screw member provided in the other joint member.

  In Patent Document 1, one joint member is a cylindrical sleeve having an outward flange, and the female screw member is an nut that has an inward flange opposite to the outward flange of the sleeve and is fitted to the sleeve. Have been disclosed.

JP 2014-84886 A

  The above-described conventional pipe joint is excellent in sealing performance by plastically deforming a gasket and performing surface sealing, and is used in various applications. For example, when the outside air temperature decreases or when the fluid to flow is a cryogenic fluid, the surface pressure applied to the sealing member such as a gasket may decrease due to the thermal contraction of the joint member or the piping material, and the sealing performance may deteriorate. is there.

  In addition, it may be used under conditions with large vibrations such as pumps and compressors. In this case, the entire pipe joint is repeatedly subjected to vibration over a long period of time, which reduces the surface pressure applied to the seal member. In some cases, the sealing performance may deteriorate. Furthermore, when a resin gasket is used, the surface pressure applied to the seal member may decrease due to the progress of creep deformation and stress relaxation of the resin, and the sealing performance may deteriorate.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a pipe joint for connecting joint members to each other. It is intended to provide a pipe joint with excellent sealing performance that does not cause fluid leakage even when the seal surface pressure is reduced, or the seal surface pressure is reduced due to creep deformation or stress relaxation of the resin gasket.

  The pipe joint according to the present invention (1), which has been made to solve the above problems, includes a pair of joint members in which a fluid passage is formed in at least one, and a female screw member into which any one of the joint members is inserted. A pipe joint in which the pair of joint members are coupled to each other by a male screw formed on the other joint member or a male screw of the male screw member attached to the other joint member and a female screw of the female screw member. The coupling member is a cylindrical sleeve having an outward flange, and the internal thread member is formed with an internal thread and an inward flange opposite to the outward flange on the inner peripheral surface, and is fitted into the sleeve. An urging member for urging both flanges outward in the axial direction is provided between facing surfaces of the directional flange and the inward flange.

  According to the pipe joint of the present invention (1), since the urging member is provided between the facing surfaces of the outward flange of the sleeve and the inward flange of the female screw member (nut), by tightening the female screw member, The urging member is compressed, and the restoring force by the urging member always works in the direction of pressing the sleeve toward the gasket. Due to this action, even if the member shrinks due to a temperature drop and the surface pressure applied to the gasket decreases, this force can press the gasket and prevent a decrease in the surface pressure of the gasket, and fluid leaks from the pipe joint. Disappears.

  Further, since the urging force by the urging member is also applied in the direction of pushing the inner surface of the inward flange of the female screw member (nut), the contact pressure between the male screw thread and the female screw thread valley is increased by the action of this force. To work. As a result, loosening of the screw due to repeated vibration is prevented, and even when the entire pipe joint is repeatedly subjected to vibration over a long period of time, sealing performance is ensured and parts are prevented from being damaged.

  Furthermore, when a resin gasket is used, the gasket may be deformed by creep deformation and stress relaxation, and the seal surface pressure may be reduced. Such a decrease in the seal surface pressure can also be prevented by the action of the urging force by the urging member.

  The screw means for coupling the joints can have various configurations. For example, both of the pair of joint members are formed with a male thread portion formed in one of the pair of joint members and screwed into the male thread portion of the joint member. A joint member may be combined, a pair of joint members may be a sleeve in which a male thread portion is not formed, and both joint members may be coupled by a male thread member and a nut which are separate members.

  The pipe joint of the present invention (2) is the joint according to the present invention (1), wherein the biasing member is a compression coil spring.

  In the present invention (2), since the urging member is a low-cost compression coil spring, the cost is not increased and the structure is simple, so that the loosening of the screw due to vibration can be stably prevented.

  The pipe joint of the present invention (3) is the joint according to the present invention (1), wherein the biasing member is one or two or more annular disc springs.

  Also in the present invention (3), since the urging member is a low-cost disc spring, the cost is not increased and the structure is simple, so that loosening due to vibration can be prevented stably.

  In the pipe joint of the present invention (4), annular ring bodies that respectively contact the outward flange and the inward flange are provided at both ends of the compression coil spring, and the ring bodies are coated with fluororesin. It is a joint as described in the present invention (2).

  In the pipe joint of the present invention (4), an annular ring body that contacts the outward flange and the inward flange is provided at both ends of the compression coil spring, and the ring body is coated with fluororesin. Further, it is possible to prevent the pipes from being turned around when the joint is fastened.

  The pipe joint of the present invention (5) is the pipe joint of the present invention (3), and when one disc spring is provided, two or more disc springs are provided at both ends of the disc spring. In this case, an annular ring body that comes into contact with the outward flange and the inward flange is provided at the axially outer ends of the disc springs at both ends, and the ring body is a pipe joint that is coated with fluororesin. .

  In the pipe joint of the present invention (5), when one disc spring is provided, the axially outer ends of the disc springs at both ends when two or more disc springs are provided at both ends of the disc spring. Are provided with annular ring bodies that respectively contact the outward flange and the inward flange, and the ring bodies are coated with fluororesin, so that it is possible to prevent the circulation of pipes and the like when the joint is fastened. it can.

  According to the pipe joint of the present invention, due to the urging force of the urging member, it is possible to prevent a decrease in the seal surface pressure due to a temperature decrease or the like, and to improve the sealing performance.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a pipe joint according to the present invention. FIG. 2 is a longitudinal sectional view showing a second embodiment of the pipe joint according to the present invention. FIG. 3 is a longitudinal sectional view showing a third embodiment of the pipe joint according to the present invention. FIG. 4 is a longitudinal sectional view showing a fourth embodiment of the pipe joint according to the present invention. FIG. 5 is a longitudinal sectional view showing a fifth embodiment of the pipe joint according to the present invention. FIG. 6 is a longitudinal sectional view showing a sixth embodiment of the pipe joint according to the present invention. FIG. 7 is a longitudinal sectional view showing a seventh embodiment of the 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, up, down, left, and right refer to up, down, left, and right in the drawings.

  FIG. 1 shows a first embodiment of a pipe joint according to the present invention. The pipe joint 1 has a joint member 3 (hereinafter also referred to as a sleeve 3) having a fluid passage 3a, and a joint member 2A. The joint member 2A does not have a fluid passage. The joint member 2A is generally called a closing plug (hereinafter also referred to as a closing plug 2A), and the closing plug 2A is used when temporarily removing a corresponding pipe and using it.

  A male screw 4a is formed on the outer periphery of the closing plug 2A, and an outward flange 5 is formed on the left end.

  An annular gasket 6 between the end face of the closing plug 2A (the right end face in the figure) and the end face of the sleeve 3 (the left end face in the figure), and a female screw member 7 (hereinafter referred to as the screw 3A) that is screwed into the closing plug 2A from the sleeve 3 side. , Also referred to as nut 7.).

  The sleeve 3 has a cylindrical shape, and an outward flange 8 is provided at the left end thereof. An inward flange 9 is provided at the right end of the nut 7.

  When the male screw 4a of the stopper plug 2A and the female screw 7a of the nut 7 are tightened and fastened, the gasket stopper annular protrusions 2b and 3b are formed on the end faces of the stopper plug 2A and the sleeve 3, respectively. The leakage of the fluid in the fluid passage 3a is surely prevented.

  The gasket 6 is made of a nickel alloy and is silver-plated as necessary. As the material of the gasket 6, austenitic stainless steel, copper, an aluminum alloy, or the like is appropriately employed.

  A biasing member (compression coil spring 12) is provided between the right end surface of the outward flange 8 of the sleeve 3 and the left end surface of the inward flange 9 of the nut 7, and a male screw 4a of the closing plug 2A and a female screw 7a of the nut 7. As a result, the compression coil spring 12 is pressed from the left and right, and as a reaction force, a force is exerted on the gasket 6 in the left direction and on the inward flange 9 in the right direction. As a result, a pressing force toward the gasket 6 is generated, and the fluid does not leak without causing a decrease in the surface pressure of the seal portion of the gasket.

  Since a force is generated in the rightward direction on the inward flange 9, the pressure that presses the threaded slope of the male screw 4a and the threaded valley slope of the female screw 7a is increased by this force, and the screw is not easily loosened.

  Adjustment of the biasing force by the compression coil spring 12 can be easily performed by appropriately determining various parameters such as the spring material, the number of turns of the spring, and the spring diameter and adjusting the spring constant.

  The pipe joint of the second embodiment shown in FIG. 2 is similar to the pipe joint of the first embodiment shown in FIG. 1, and the urging member is changed from the compression coil spring 12 to the disc spring 13. In the pipe joint shown in FIG. 2, five disc springs 13 are arranged to face each other.

  As in the case of the compression coil spring 12 of the first embodiment shown in FIG. 1, when the male screw 4a of the stopper plug 2A and the female screw 7a of the nut 7 are tightened and fastened, the disc spring 13 is pressed from the left and right, and the reaction force is The gasket 6 exerts a force in the direction toward the left, and the inward flange 9 exerts a force in the direction toward the right. As a result, a pressing force toward the gasket 6 is generated, and the fluid does not leak without causing a decrease in the surface pressure of the seal portion of the gasket.

  Since a force is generated in the rightward direction on the inward flange 9, the pressure that presses the threaded slope of the male screw 4a and the threaded valley slope of the female screw 7a is increased by this force, and the screw is not easily loosened.

  Adjustment of the urging force by the disc spring 13 can be easily performed by appropriately determining various parameters such as the disc spring material and the shape of the disc spring.

  The pipe joint of the third embodiment shown in FIG. 3 is similar to the pipe joint of the first embodiment shown in FIG. 1, and is a circle that contacts the outward flange 8 and the inward flange 9 at both ends of the compression coil spring 12. An annular ring body 14 is provided, and the ring body 14 is a pipe joint coated with a fluororesin. Since it is coated with fluororesin, the coefficient of friction with the inner surfaces of the outward flange 8 and the inward flange 9 becomes small, so that the sleeve 3 and the like cannot be used at the time of fastening.

  In the pipe joint of Example 4 shown in FIG. 4, the joint member 2 is a sleeve having a fluid passage 2a (hereinafter referred to as the sleeve 2), and an outward flange 8 is formed at the right end portion thereof. The male screw member 4 is fitted into the sleeve 2 from the left side, and the male screw 4a formed on the male screw member 4 and the female screw 7a of the nut 7 are screwed together, and the pipe joint 1 is fastened.

  A compression coil spring 12 is provided between the right end surface of the outward flange 8 of the sleeve 3 and the left end surface of the nut 7. As in the first embodiment shown in FIG. 1, an urging member (compression coil spring 12) is provided between the right end surface of the outward flange 8 of the sleeve 3 and the left end surface of the inward flange 9 of the nut 7. When the male screw 4a 4 and the female screw 7a of the nut 7 are tightened and fastened, the compression coil spring 12 is pressed from the left and right, and as a reaction force, the gasket 6 is directed leftward and the inward flange 9 is directed rightward. Energize in the direction you head. As a result, a pressing force toward the gasket 6 is generated, and the fluid does not leak without causing a decrease in the surface pressure of the seal portion of the gasket.

  Since a force is generated in the rightward direction on the inward flange 9, this force increases the pressure of the threaded slope of the male screw 4 a and the threaded slope of the female screw 7 a against each other, making it difficult for the screw to loosen.

  The pipe joint of the fifth embodiment shown in FIG. 5 is similar to the pipe joint of the fourth embodiment shown in FIG. 4, and the compression coil spring 12 is changed to a disc spring 13, and the operation and effects thereof are shown in FIG. Since it is the same as that of the pipe joint of Example 2, description is abbreviate | omitted.

  The pipe joint of Example 6 shown in FIG. 6 is similar to the pipe joint of Example 5 shown in FIG. 5, and is provided with ring bodies 14 of Example 3 shown in FIG. The effect is the same as that of the pipe joint of Example 3 shown in FIG.

  The pipe joint of Example 7 shown in FIG. 7 includes a male screw member 4 having a male screw 4a and a female screw member 7 (hereinafter also referred to as a nut 7) that is screwed with the male screw 4a. The nut 7 has a shape similar to that shown in FIGS.

  The pipe member 3B is fitted into the nut 7 and the male screw 4a of the male screw member 4 and the female screw 7a of the nut 7 are tightened, whereby the pipe member 3B and the male screw member 4 are fastened to constitute the pipe joint 1. As a seal mechanism for fastening the pipe member 3B, two rings (a front ring FR and a back ring BR) are provided, and the back ring BR has an outward flange BRa.

  When the tube member 3B and the male screw member 4 are fastened, the two rings FR and BR bite into the tube member 3B and are integrated. Since the tube member 3B and the buckling BR having the outward flange BRa are integrated, the tube member 3B has a function equivalent to that of the sleeve 3 of FIG.

  A biasing member (compression coil spring 12) is provided between the right end surface of the outward flange BRa and the left end surface of the inward flange 9 of the nut 7. The urging member may be a disc spring, and the effect is the same as that of the pipe joints of Examples 1 to 6 shown in FIGS.

  As described above, according to the present invention, when the seal surface pressure decreases due to temperature change, when the seal surface pressure when the entire pipe is subjected to vibration decreases, the seal surface pressure decreases due to the creep phenomenon of the resin gasket. It can be suitably used even under circumstances. At this time, the existing pipe joint can be improved and used by adding an urging member (compression coil spring, disc spring, etc.).

1: Pipe fitting 2: Sleeve (joint member)
2a: Fluid passage 2b: Annular projection 2A: Closure plug (joint member)
3: Sleeve (joint member)
3a: Fluid passage 3b: Annular protrusion 4: Male screw member 4a: Male screw
5: outward flange
6: Gasket 7: Nut (female screw member)
7a: Female thread 8: Outward flange 9: Inward flange 12: Compression coil spring (biasing member)
13: Belleville spring (biasing member)
14: Ring body

Claims (4)

A pair of coupling members having a fluid passage formed in at least one of them;
A female screw member through which any one of the joint members is inserted,
In the pipe joint in which the pair of joint members are coupled to each other by the male screw formed on the other joint member or the male screw of the male screw member attached to the other joint member and the female screw of the female screw member,
The one joint member is a cylindrical sleeve having an outward flange,
The female screw member is formed with an internal thread and an inward flange opposite to the outward flange on the inner peripheral surface, and the sleeve is fitted therein.
A pipe joint comprising a biasing member for biasing both flanges outward in the axial direction between opposing surfaces of the outward flange and the inward flange.   The pipe joint according to claim 1, wherein the biasing member is a compression coil spring.   The pipe joint according to claim 1, wherein the urging member is one or more annular disc springs. 2. The joint according to claim 1, wherein an annular ring body that contacts the outward flange and the inward flange is provided at both ends of the biasing member, and the ring body is coated with a fluororesin.

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