Pipe joint structure and assembly method of the same

Abstract

To provide a pipe joint structure which enables reduction of a risk that a nut comes loose during use of a pipe, and to provide an assembly method of the pipe joint structure.SOLUTION: A pipe joint structure 1 includes: a first pipe 20 or a second pipe 21; a joint body 30 into which an end of the first pipe 20 or the second pipe 21 is inserted; and nuts 50 each of which is screwed into the joint body 30 to fasten the first pipe 20 or the second pipe 21 to the joint body 30. The nut 50 has: a pin 52 provided at the side facing the joint body 30; and a spring 53 which biases the pin 52 to the side of the joint body 30. The joint body 30 has pin grooves 39 which are provided at the side facing the nut 50. When the nut 50 fastens the first pipe 20 or the second pipe 21 to the joint body 30, the pin 52 is inserted into the pin groove 39. Thus, the structure can reduce a risk that the nut comes loose during use of the pipe.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a pipe joint structure and an assembly method thereof. [Background technology]

[0002] A known example of an expansion type fitting is the one described in Patent Document 1, which involves expanding (expanding) the area near the end of a stainless steel pipe used for cold and hot water supply piping to form an expanded section, then inserting the pipe end into the fitting body and tightening a nut over the expanded section, thereby sealing the fitting body with water and preventing the pipe from coming loose. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-318459 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the pipe expansion joint described in Patent Document 1 had the problem that if the nut was not tightened properly or if excessive vibration, pressure changes, thermal contraction, or thermal expansion occurred during use of the piping, the nut could loosen, reducing the force pressing the stainless steel pipe against the sealing material, which could result in fluid leaking from the gap between the stainless steel pipe and the joint body.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a pipe joint structure and an assembly method thereof that can reduce the possibility of nuts loosening during use of the pipe. [Means for solving the problem]

[0006] The pipe fitting structure of the present invention comprises a pipe, a pipe fitting into which an end of the pipe is inserted, and a nut that screws onto the pipe fitting and fastens the pipe and the pipe fitting, the nut having a pin provided on the side facing the pipe fitting and an elastic member that urges the pin toward the pipe fitting, the pipe fitting having a groove portion provided on the side facing the nut, and the pin being inserted into the groove portion when the nut fastens the pipe and the pipe fitting.

[0007] The elastic member may be a coil spring, the nut may have a pin retaining hole formed opposite the pipe fitting and a stopper that seals the side of the pin retaining hole away from the pipe fitting, and the elastic member may be provided between the stopper and the pin.

[0008] A method for assembling a pipe fitting structure according to the present invention includes a pipe, a pipe fitting into which an end of the pipe is inserted, and a nut that threads onto the pipe fitting to fasten the pipe and the pipe fitting, the nut having a pin provided on the side facing the pipe fitting and an elastic member that biases the pin towards the pipe fitting, and the pipe fitting having a groove provided on the side facing the nut, the method comprising the steps of: threading the nut onto the pipe fitting; when the pin is in a position other than the groove of the pipe fitting when the nut is threaded onto the pipe fitting, the pipe fitting presses the pin to accommodate it inside the nut; and when the pin is in a position in the groove of the pipe fitting when the nut is threaded onto the pipe fitting, inserting the pin into the groove. [Effects of the Invention]

[0009] According to the present invention, the pipe fitting structure includes a nut that fastens a pipe to the pipe fitting, the nut having a pin provided on the side facing the pipe fitting and an elastic member that urges the pin toward the pipe fitting, and the pipe fitting having a groove portion provided on the side facing the nut, and when the nut fastens the pipe to the pipe fitting, the pin is inserted into the groove portion, thereby reducing the possibility of the nut loosening while the pipe is in use.

[0010] Furthermore, according to the present invention, the method for assembling a pipe fitting structure includes a step of screwing a nut onto the pipe fitting, a step of having the pipe fitting press the pin to accommodate it inside the nut when the pin is in a position other than the groove of the pipe fitting when the nut is screwed onto the pipe fitting, and a step of inserting the pin into the groove when the pin is in a position in the groove of the pipe fitting when the nut is screwed onto the pipe fitting, thereby reducing the possibility of the nut loosening while the pipe is in use. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a partial cross-sectional exploded view of a pipe joint structure according to an embodiment of the present invention; [Figure 2] FIG. 2 is a front view of the pin, spring, stopper, and pin tip shown in FIG. [Figure 3] 2 is a perspective view of the joint body and the nut shown in FIG. 1 in a screwed state. FIG. [Figure 4] 1 is a partial cross-sectional view of a pipe joint structure in a state where a nut is temporarily fastened to a joint body. [Figure 5] FIG. 10 is a partial cross-sectional view of the pipe joint structure in a state where the nut is fully tightened onto the joint body. [Figure 6] 6 is an enlarged cross-sectional view showing the threaded portion between the joint body and the nut on the second pipe side shown in FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional exploded view of a pipe joint structure according to an embodiment of the present invention. The pipe joint structure 1 is used in piping equipment installed in commercial facilities, homes, factories, etc., and includes a first pipe 20, a second pipe 21, and a joint body 30 connecting these pipes. The first pipe 20 and the second pipe 21 are metal pipes through which fluids, including various gases or liquids such as refrigerants, high-temperature or low-temperature gases, hot water, or cold water, flow. The first pipe 20 has a first expanded pipe section 22 with an expanded diameter, and the second pipe 21 has a second expanded pipe section 23 with an expanded diameter. The first expanded pipe section 22 and the second expanded pipe section 23 are formed by expanding the diameter of portions of the first pipe 20 and the second pipe 21 using a known expanding tool. The first pipe 20 and the second pipe 21 can be formed from any metal material, such as stainless steel, copper, or an aluminum alloy.

[0013] The joint body 30 is a tubular joint made of any metal material, such as stainless steel, copper, or aluminum alloy. The joint body 30 has a protruding portion 31 that protrudes radially outward at the center of the central axis. Ring-shaped joint grooves 32 are formed on both sides of the protruding portion 31. In the following description, the direction in which the radial central axes of the joint body 30, the first pipe 20, and the second pipe 21 extend is referred to as the X direction. In the following description, the X, Y, and Z directions are mutually orthogonal directions. Specifically, the Z direction is the vertical direction, and the X and Y directions are horizontal directions orthogonal to the vertical direction. The Z direction is referred to as the height direction, and the higher side in the Z direction is referred to as the upper side and the lower side in the Z direction is referred to as the lower side. A male thread portion 33 is provided adjacent to the joint groove 32. The joint groove 32 has a smaller outer diameter than the male thread portion 33 and is formed in a perfect circle when viewed along the X direction. Furthermore, the end portion 34 of the joint body 30 adjacent to the male thread portion 33 is formed to have a smaller outer diameter than the male thread portion 33. A ring-shaped joint edge portion 36 that protrudes radially inward is formed on the inner diameter portion of each end portion 34. The joint body 30 constitutes a piping joint.

[0014] In the inner diameter portion of the joint body 30, the inner diameter of the protruding portion 31 is smaller than the inner diameter of the male thread portion 33. The inner diameter of the protruding portion 31 is also smaller than the outer diameters of the first pipe 20 and the second pipe 21, and the inner diameter of the male thread portion 33 is formed so that the first pipe 20 and the second pipe 21 can be fitted thereto. Furthermore, annular rubber ring grooves 35 are formed near one outer end and the other outer end of the inner diameter portion of the male thread portion 33. The inner diameter of the joint edge portion 36 is smaller than the outer diameters of the first expanded pipe portion 22 of the first pipe 20 and the second expanded pipe portion 23 of the second pipe 21. Annular rubber rings 38 are attached to each rubber ring groove 35. The rubber rings 38 are made of any rubber material, such as a ternary fluororubber.

[0015] Nuts 50, which are nuts made of any metal material such as stainless steel, copper, or aluminum alloy, are attached to the joint body 30 to secure the first pipe 20 and the second pipe 21 to the joint body 30. With the first pipe 20 and the second pipe 21 inserted into the joint body 30, the nut 50 is fastened to the joint body 30 by threading a female thread portion 51 formed inside the nut 50 onto a male thread portion 33 of the joint body 30, thereby fixing and connecting the first pipe 20 and the second pipe 21 to the joint body 30. Pin grooves 39, into which pins 52 provided on the nuts 50 are inserted, are formed on each surface of the protruding portion 31 of the joint body 30 facing each nut 50. The pin grooves 39 constitute grooves.

[0016] A pin retaining hole 56, which is a circular hole extending along the X direction, is formed on the radially outer side of the nut 50. A stopper 54 is press-fitted into the pin retaining hole 56 on the side opposite the side facing the joint body 30. The stopper 54 is formed of any metal material, such as stainless steel, copper, or aluminum alloy. A coil spring 53 is inserted into the pin retaining hole 56 so as to contact the stopper 54, and a cylindrical pin 52 is inserted so as to contact the spring 53. The stopper 54 seals the side of the pin retaining hole 56 opposite the side facing the joint body 30, thereby retaining the spring 53 and pin 52 within the pin retaining hole 56 to prevent them from falling out. As a result, the pin 52 is located on the side of the nut 50 facing the joint body 30. The spring 53 constitutes an elastic member.

[0017] 2 is a front view of the pin 52, spring 53, stopper 54, and pin tip 55 shown in FIG. The configuration of the pin 52 will be described with reference to FIGS. 1 and 2. The spring 53 is disposed between the stopper 54 and the pin 52 and biases the pin 52 toward the side facing the joint body 30. The end of the pin 52 facing the joint body 30 is formed with a pin tip 55 having a smaller diameter than the rest of the pin 52. Because the pin 52 is biased by the spring 53, when the nut 50 is not fastened to the joint body 30, the pin tip 55 protrudes outside the pin retaining hole 56 on the side facing the joint body 30. The pin 52 is formed of any metal material, such as stainless steel, copper, or an aluminum alloy.

[0018] Fig. 3 is a perspective view of the joint body 30 and nut 50 shown in Fig. 1 in a screwed state. The protruding portion 31 of the joint body 30 has a rectangular columnar shape corresponding to the shape of the outer shape of the nut 50. One of the six faces of the protruding portion 31 has a pin groove 39 formed along a direction perpendicular to the axial direction of the joint body 30 (the X direction shown in Fig. 1).

[0019] Next, a method for connecting the first pipe 20 and the second pipe 21 of the pipe joint structure 1 using the joint body 30 will be described. First, the pin 52 and spring 53 are inserted in this order into the pin holding hole 56 of the nut 50 shown in FIG. 1 , and then the stopper 54 is press-fitted into the pin holding hole 56 to fix it in place. Next, rubber rings 38 are placed in the two rubber ring grooves 35 of the joint body 30. Next, the first pipe 20 is inserted into the nut 50, and the first expanded portion 22 is formed using a known expanding tool. Furthermore, the second pipe 21 is inserted into the nut 50, and the second expanded portion 23 is formed using a known expanding tool.

[0020] FIG. 4 is a partial cross-sectional view of the pipe fitting structure 1 with the nuts 50 temporarily fastened to the fitting body 30. After the first expanded pipe portion 22 and the second expanded pipe portion 23 are formed, the first pipe 20 and the second pipe 21 are inserted into the fitting body 30. Next, the female thread portion 51 of the nut 50 on the first pipe 20 side is manually threaded onto the male thread portion 33 of the fitting body 30, and the female thread portion 51 of the nut 50 on the second pipe 21 side is manually threaded onto the male thread portion 33 of the fitting body 30. This attaches each nut 50 to the fitting body 30 in a temporarily fastened state. The temporarily fastened position of each nut 50 at this time constitutes the first position.

[0021] When the nut 50 is temporarily fastened to the joint body 30 , the pin tip 55 of the pin 52 attached to the nut 50 is not inserted into the pin groove 39 of the joint body 30 .

[0022] Next, each nut 50 is further tightened onto the joint body 30 using a tool such as a pipe wrench to fully tighten it. As the nuts 50 are tightened, the pin tips 55 rotate together with the nuts 50 and approach the protruding portions 31 of the joint body 30. When the nuts 50 are further tightened, the pin tips 55 come into contact with the ends of the protruding portions 31. After the pin tips 55 come into contact with the ends of the protruding portions 31, when the nuts 50 are further tightened, the pin tips 55 are pressed against the protruding portions 31, the springs 53 are compressed and contracted, and the pins 52 and pin tips 55 are accommodated inside the pin retaining holes 56.

[0023] When the nut 50 is further tightened, the pin tip 55 of the pin 52, which rotates together with the nut 50 as shown in Figure 3, moves to the position of the pin groove 39 in the protruding portion 31 of the joint body 30. When the pin tip 55 moves to the position of the pin groove 39, the spring 53 (see Figure 4) expands, and the pin 52 is biased by the spring 53, so that the pin tip 55 is inserted into the pin groove 39.

[0024] 5 is a partial cross-sectional view of the pipe fitting structure in a state where the nut 50 has been fully tightened onto the fitting body 30. The pin tip 55 of the pin 52 is inserted into the pin groove 39 of the fitting body 30. At this time, the rubber rings 38 serving as sealing materials are pressed and crushed by the first expanded portion 22 and the second expanded portion 23, thereby sealing the gap between the first pipe 20 and the fitting body 30 and the gap between the second pipe 21 and the fitting body 30, thereby preventing leakage of fluid flowing through the first pipe 20 and the second pipe 21. The fully tightened position, which is the position of each nut 50 at this time, constitutes the second position.

[0025] Figure 6 is an enlarged cross-sectional view showing the threaded portion between the joint body 30 and the nut 50 on the second pipe 21 side shown in Figure 5. Note that although Figure 6 shows the configuration of the threaded portion between the joint body 30 and the nut 50 on the second pipe 21 side, the configuration of the threaded portion between the joint body 30 and the nut 50 on the first pipe 20 side is similar. The pin 52 is biased by a spring 53, and the pin tip 55 is inserted into the pin groove 39 of the joint body 30.

[0026] Because the pin tips 55 are inserted into the pin grooves 39, the rotational distance that each nut 50 can rotate relative to the fitting body 30 is limited to the rotational distance corresponding to the length of the pin grooves 39, as shown in Fig. 3. Therefore, even if torque is generated in a direction that loosens the nut 50 after the nut 50 is fully tightened due to factors such as excessive vibration between the first pipe 20 and the second pipe 21, pressure changes in the fluid in the pipes, thermal contraction, and thermal expansion that occur during operation of the piping equipment in which the pipe fitting structure 1 is installed, the nut 50 will not loosen beyond the rotational distance corresponding to the length of the pin grooves 39. Therefore, loosening of the nut 50 due to various factors that loosen the torque of the nut 50 that occur during operation of the piping equipment as described above is suppressed.

[0027] Next, a method for loosening each nut 50 to disconnect the fitting body 30 from the first pipe 20 and the second pipe 21 when the fitting body 30 and the first pipe 20 and the second pipe 21 are connected by fully tightening the nuts 50 as shown in FIG. 5 is described. To loosen the nut 50, the pin tip 55 is pushed into the pin retaining hole 56 through the pin groove 39 with a tool or by hand while loosening the nut 50. This allows the nut 50 to be loosened by a distance in the rotational direction equal to or greater than the length of the pin groove 39. This releases the engagement between the fitting body 30 and each nut 50, thereby disconnecting the fitting body 30 from the first pipe 20 and the second pipe 21. Furthermore, because there is no need to destroy components such as the pin 52 and the pin groove 39 when loosening each nut 50 from a fully tightened state, the same nut 50 and fitting body 30 can be used to connect and disconnect the first pipe 20 and the second pipe 21 multiple times.

[0028] As described above, the pipe fitting structure of this embodiment comprises the first pipe 20 or the second pipe 21, a fitting body 30 into which the end of the first pipe 20 or the second pipe 21 is inserted, and a nut 50 that threads onto the fitting body 30 and fastens the first pipe 20 or the second pipe 21 to the fitting body 30, the nut 50 having a pin 52 provided on the side facing the fitting body 30 and a spring 53 that urges the pin 52 toward the fitting body 30, the fitting body 30 having a pin groove 39 provided on the side facing the nut 50, and when the nut 50 fastens the first pipe 20 or the second pipe 21 to the fitting body 30, the pin 52 is inserted into the pin groove 39, thereby reducing the possibility of the nut loosening during use of the pipe.

[0029] In addition, the spring 53 is a coil spring, and the nut 50 has a pin retaining hole 56 formed opposite the joint body 30 and a stopper 54 that blocks the side of the pin retaining hole 56 away from the joint body 30. Since the spring 53 is provided between the stopper 54 and the pin 52, it is easy to both prevent the nut 50 from loosening by inserting the pin 52 into the pin groove 39 through the extension of the spring 53, and to allow the nut 50 to loosen by not inserting the pin 52 into the pin groove 39 through the contraction of the spring 53.

[0030] Further, as described above, the method for assembling the pipe joint structure according to the present embodiment includes a first pipe 20 or a second pipe 21, a joint body 30 into which an end of the first pipe 20 or the second pipe 21 is inserted, and a nut 50 that is threaded onto the joint body 30 and fastens the first pipe 20 or the second pipe 21 and the joint body 30, the nut 50 having a pin 52 provided on the side facing the joint body 30 and a spring 53 that urges the pin 52 toward the joint body 30, and the joint body 30 having a pin groove 39 provided on the side facing the nut 50. In the pipe fitting structure 1 having the above structure, there are included a step of screwing the nut 50 onto the fitting body 30, a step of pressing the pin 52 against the fitting body 30 and contracting it when the pin 52 is in a position other than the pin groove 39 of the fitting body 30 when the nut 50 is screwed onto the fitting body 30, and a step of extending the pin 52 and inserting it into the pin groove 39 when the pin 52 is in the position of the pin groove 39 of the fitting body 30 when the nut 50 is screwed onto the fitting body 30, thereby reducing the possibility of the nut loosening during use of the pipe.

[0031] In the embodiment of the present invention, a coil spring is used as spring 53, but the present invention is not limited to this, and springs other than coil springs or elastic members such as rubber may also be used.

[0032] Furthermore, the shape of the pin groove 39 of the joint body 30 in the embodiment of the present invention is an example and is not limited thereto, and any shape may be used as long as the pin 52 is inserted into the pin groove 39 to limit the rotation range of the nut 50 relative to the joint body 30. For example, a pin groove having a length shorter than the pin groove 39 in the embodiment may be used. Furthermore, the pin groove 39 may be formed on two or more surfaces of the protruding portion 31. [Explanation of symbols]

[0033] 20 first pipe, 21 second pipe, 30 joint body (pipe joint), 39 pin groove (groove portion), 50 nut (fastening member), 52 pin, 53 spring (elastic member), 54 stopper, 56 pin retaining hole.

Claims

1. Piping and a pipe joint into which the end of the pipe is inserted; a nut that is screwed onto the pipe joint and fastens the pipe and the pipe joint; Equipped with The nut has a pin provided on a side facing the pipe joint and an elastic member that biases the pin toward the pipe joint, The pipe joint has a groove provided on a side facing the nut, A pipe joint structure in which the pin is inserted into the groove when the nut fastens the pipe and the pipe joint.

2. The elastic member is a coil spring, The nut has a pin holding hole formed facing the pipe joint and a stopper that closes the pin holding hole on the side away from the pipe joint, The pipe joint structure according to claim 1 , wherein the elastic member is provided between the stopper and the pin.

3. Piping and a pipe joint into which the end of the pipe is inserted; a nut that is screwed onto the pipe joint and fastens the pipe and the pipe joint; Equipped with The nut includes a pin provided on a side facing the pipe joint, and an elastic member that biases the pin toward the pipe joint. and The pipe joint has a groove provided on a side facing the nut, threading the nut onto the pipe joint; a step of, when the nut is screwed onto the pipe joint and the pin is in a position other than the groove of the pipe joint, causing the pipe joint to press the pin and accommodate it inside the nut; and when the pin is positioned in a groove portion of the pipe fitting when the nut is screwed onto the pipe fitting, inserting the pin into the groove portion.

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