JPH0581592U - Pipe fitting - Google Patents

Abstract

(57) [Abstract] [Objective] The purpose of the present invention is to keep the tightening force of the biting member on the pipe almost constant even if there is some variation in the nut tightening position in the axial direction. Provided is a pipe joint that can be tightened by an appropriate biting force into a pipe even when the nut is completely tightened at a position. [Composition] By mounting a biting member between a joint body and a nut screwed to the joint body and tightening the nut, the biting member reduces the outer surface of the connecting pipe mounted in the joint body. In a pipe joint that prevents the connection pipe from pulling out, the biting member is a thin wall that is pressed toward the joint body side by contacting a front end surface that abuts on the joint body, an inner bite surface that abuts the outer surface of the connection pipe, and a pressing surface of the nut A tube characterized by comprising a cylindrical portion, wherein the biting member is pressed toward the joint body side by tightening the nut to reduce the diameter, and the thin-walled cylindrical portion is deformed to keep the tightening force on the tube substantially constant. It is a joint.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention, when connecting the connection pipe to the joint body, keeps the tightening and biting amount of the nut almost constant even if the tightening position and amount of the nut change to some extent, thereby absorbing the wall thickness of the connection pipe and connecting work. It relates to a pipe joint that can be made.

[0002]

[Prior Art]

 Conventionally, as a pipe joint used for a resin pipe, there is one shown in FIG. 9 disclosed in Japanese Utility Model Laid-Open No. 2-56994. In this pipe joint, a mounting portion 92 of the connecting pipe 91 is formed at one end of the joint body 90, and the outer surface of the connecting pipe 91 mounted on the mounting portion 92 is tightened with a cap nut 94 with a biting member 93 having biting teeth on the inner surface. The diameter is reduced to prevent the pipe 91 from pulling out.

In this type of pipe joint, it is difficult to understand the tightening amount and the tightening position of the nut 94, and if the tightening is too strong, the pipe 91 is deteriorated. If the tightening is insufficient, the biting member does not completely bite into the pipe 91. Therefore, the problem of pipe coming out and leakage occurs. To prevent this, mark the nut tightening end position on the outer surface of the connecting pipe 91, or set the nut tightening end position when the end surface of the nut contacts the joint body. It was

[0004]

[Problems to be solved by the device]

 However, in general, the wall thickness of the resin pipe varies greatly, and if the wall thickness of the pipe is large, the bite of the biting member into the pipe ends early, so the nut tightening position may be shallow, and if the pipe wall is thin. If you do not tighten the nut deeply, the amount of bite into the pipe will be insufficient. Therefore, there was a problem in defining the tightening end position of the nut in the axial direction of the pipe. In other words, even if the tightening position of the nut is set so that the wall thickness is the proper tightening position in the standard state, if the wall thickness is large, a large tightening torque is applied to tighten to the set position, Excessive biting into the tube. In addition, if the pipe is thin, even if it is tightened to the set position, the amount of bite into the pipe will be insufficient, and the force to prevent the pipe from pulling out will be insufficient, causing leakage. The present invention keeps the tightening force of the biting member to the pipe almost constant even if there is some variation in the axial tightening position of the nut. Even so, it is intended to provide a pipe joint that can be tightened by an appropriate biting force into a pipe.

[0005]

[Means for Solving the Problems]

 The gist of the present invention is to install a biting member between a joint body and a nut screwed to the joint body and tighten the nut so that the bite member shrinks the outer surface of the connecting pipe mounted in the joint body. In a pipe joint with a diameter that prevents the connection pipe from pulling out, the biting member is a biting member that abuts the front end surface that abuts the joint body and the outer surface of the connecting pipe, and the inner surface of the bite and the pressing surface of the nut. It is characterized in that when the nut is tightened, the bite member is pressed toward the joint body side to reduce the diameter, and at the same time the thin-walled cylindrical part is deformed and the tightening force to the pipe is kept almost constant. This is a pipe joint.

[0006]

[Action]

 Since the present invention has the above-described structure, the biting member in the process of tightening the nut on the joint body is first the end face of the thin-walled cylindrical portion provided on the biting member being pressed by the pressing surface of the nut so that the biting member is a joint. The bite member starts contact with the main body to start reducing the diameter. When the biting part on the inner surface of the biting member comes into contact with the outer surface of the connecting pipe to bite into the pipe, and when the specified amount of biting is performed on the outer surface of the pipe, the required nut tightening torque is reached and the biting part material is reached. The reduction of diameter stops while being pressed by the nut, and then the thin-walled cylindrical portion begins to deform along the inner surface of the nut in order from the contact end side. Since the thin-walled cylindrical part has a length in the axial direction, the pressing force of the biting member to the joint body side is almost constant while the thin-walled cylindrical part is deformed, and therefore the pressing force to the outer surface of the pipe is also almost constant. The nut can be tightened and rotated in this state.

Therefore, for example, when the specified tightening position of the nut is set to the position where the nut abuts on the joint body, and when connecting a pipe having a large wall thickness of the connecting pipe, the biting member is not bitten into the pipe. After the completion, deformation of the thin-walled cylindrical part to the inner surface side begins and even if the nut is tightened to the specified position, excessive biting into the pipe can be prevented. Even if the wall thickness of the pipe is small, it is sufficient that the nut tightening reaches the specified position when the thin-walled cylinder part is slightly deformed after the biting member has finished biting into the pipe. For this reason, even if the wall thickness of the pipe to be connected varies, the amount of bite into the pipe is almost constant and the nut can be connected at the specified tightening position, and insufficient tightening or excessive tightening can be performed during connection work. There is no need to make an appropriate connection under certain construction conditions.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, the upper half is a cross-sectional view showing a state before tightening in which the pipe 2 is inserted into the joint body 1 and the nut 3 is screwed, and the lower half is a cross-sectional view after completion of nut tightening. The joint body 1 has an annular pipe mounting portion 12 on the inner surface side of the external thread 11 on the outer surface of the end portion, and the pipe charging portion 12 is provided with a cylindrical protruding portion 14 having a plurality of grooves 13 on the outer peripheral surface. , The inner surface of the connecting pipe 2 is sealed. The inner surface side of the cylindrical protruding portion 14 serves as a through flow passage 15 of the joint body 1. Further, a taper inner surface 18 is formed on the inner surface of the end of the pipe mounting portion 12, and the front end of the biting member 4 abuts to reduce the diameter.

The nut 3 has a female thread 31 to be screwed into the male thread 11 of the joint body 1 and a taper inner surface 32 at the inner side thereof, and abuts on the rear end of the biting member. As shown in FIG. 2, the biting member 4 has a slit 41 at one position on the circumference and a taper outer surface 46 on the front and rear end outer surfaces. The front taper outer surface 46 abuts the taper inner surface 18 of the joint body 1, and the rear taper outer surface 43 abuts the taper inner surface 32 of the nut. The front part of the inner surface is provided with a plurality of teeth 42 that bite into the outer surface of the tube 2 to prevent the tube from pulling out. There is a space 45 on the inner surface of the rear portion and a thin-walled cylindrical portion 44 along the outer surface 43 of the taper.

3, FIG. 4 and FIG. 5 are partial sectional views of FIG. 1 showing a deformed state of the biting member 4 accompanying the tightening process of the nut 3 when connecting the pipe 2. FIG. 3 shows a state in which the pipe 2 is inserted into the joint body 1 and the nut 3 is started to be tightened. First, the taper outer surface 43 of the biting member 4 contacts the taper inner surface 32 of the nut. In FIG. 4, as the tightening of the nut 3 progresses, the taper outer surface 43 of the biting member 4 is pressed by the taper inner surface 32 of the nut 3, the entire biting member 4 is reduced in diameter, and the teeth 42 bite into the outer surface of the pipe. , The thin-walled cylindrical portion 44 has started to undergo diameter-reducing deformation toward the inner diameter side along the taper inner surface 32 of the nut 3.

The front end portion of the biting member 4 is reduced in diameter by the taper inner surface 18 of the main body 1 so that the teeth 42 bite into the pipe 2 to prevent the pulling-out of the pipe and the sealing performance, and then the thin-walled cylindrical portion 44. Begins to deform. In order to obtain a state in which the thin-walled cylindrical portion 44 is deformed after sufficiently securing the teeth 42 in this way, the thin-walled cylindrical portion 42 has a thickness of the tooth 42 when the outer diameter of the pipe is 10 mm to 50 mm. 40 to 65% of the thickness of the thick portion is desirable. FIG. 5 shows a state where the tightening of the nut is increased and the thin cylindrical portion 44 is further deformed. Even when tightening progresses from the state of FIG. 4 to the state of FIG. 5, the tightening torque of the nut 3 is almost constant and the torque does not increase so much.

FIG. 8 illustrates the relationship between the tightening torque of the nut and the tightening torque of the nut when the outer diameter of the pipe is 13 mm. To explain in comparison with the states of FIGS. 3 to 4, when the wall thickness of the pipe 2 is the standard dimension, the state of FIG. 3 is the point A, and the tightening torque of the nut increases as the nut 3 is tightened. , 2.5 Kgf · m, the thin cylindrical portion 44 of the biting member 4 begins to deform. This torque causes the teeth 42 to bite into the outer surface of the tube 2. After that, even if the tightening amount of the nut 3 increases, the tightening torque rises gently to reach the point B. The state of the connecting portion at this time is the state shown in FIG. When the nut 3 is further tightened, the thin-walled cylindrical portion 44 of the bite member is further reduced in diameter and reaches point C. The state at this time is shown in FIG. When the nut tightening amount reaches point D, the deformation of the thin-walled cylindrical part is almost completed, and after that, the tightening torque starts to rise again.

Next, when the wall thickness of the pipe 2 is thicker than the standard size, as shown in FIG. 8, the tightening torque starts to increase from an earlier stage than when the nut is tightened with the standard size. Then, a curve similar to the standard size curve is drawn to increase the torque, and the curve is in the state of parallel translation to the left. When the wall thickness of the tube 2 is thicker than the standard size, the curve is similar to the state in which it is translated to the right. Therefore, if the tightening position of the nut is set, for example, if the tightening end position is the position indicated by the arrow, it will be approximately 3 Kgf. The tightening amount can be ended with an appropriate tightening torque of m. Therefore, in the present embodiment, the tightening completion position shown in the lower half of FIG. 1 is at the position of the arrow in FIG. It hits against. Therefore, even if the pipe is thick or thin, it can be tightened with almost the same tightening torque, and the amount of bite into the pipe can be made almost constant.

FIG. 7 shows another embodiment. The thin cylindrical portion 44 at the rear end of the biting member 4 spreads in a trumpet shape from the inner surface side to the outer surface side and contacts the rear inner surface of the nut 3. The inner surface of the nut 3 is a surface 34 perpendicular to the axis, and the taper outer surface 46 of the biting member abuts the taper inner surface 18 of the main body 1 in accordance with the tightening amount of the nut 3 to reduce the diameter. Begins. The thin cylindrical portion 44 at the rear end of the post-feeding member 4 undergoes buckling deformation, and the tightening amount advances with a gradual increase in tightening torque. In this embodiment, when the thickness of the thin portion is 40 to 70% of the thickness of the thick portion of the front portion, a curve similar to that shown in FIG. 8 is obtained.

[0015]

[Effect of the device]

 As described above, in the pipe joint of the present invention, even if the wall thickness of the pipe to be connected fluctuates, the amount of bite into the pipe is almost constant and the connection can be completed at the position where the nut is set. At this time, proper connection work can be performed under constant tightening conditions without causing problems due to insufficient tightening or excessive tightening.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention before and after tightening a nut.

FIG. 2 is a perspective view of a biting member showing an embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of FIG. 1 at the start of tightening the nut.

FIG. 4 is a partial sectional view of the nut of FIG. 1 during tightening.

5 is a partial cross-sectional view at the end of tightening the nut in FIG.

FIG. 6 is a cross-sectional view showing another embodiment of the present invention before and after tightening the nut.

FIG. 7 is a sectional view showing a nut according to another embodiment of the present invention before and after tightening the nut.

FIG. 8 is a diagram showing a relationship between a nut tightening amount and a tightening torque.

FIG. 9 is a partial cross-sectional view after connection showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joint main body 2 Pipe 3 Nut 4 Biting member 12 Pipe mounting portion 18 Main body taper surface 32 Nut taper inner surface 43, 46 Tapering member taper outer surface 44 Thin-walled cylindrical portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Inagaki 2 Daifuku, Kuwana City, Mie Prefecture Kuwana Plant, Hitachi Metals Ltd.

Claims (1)

[Scope of utility model registration request] 1. A biting member is mounted between a joint main body and a nut screwed to the joint main body, and the nut is tightened to reduce the outer diameter of the connection pipe mounted in the joint main body by the biting member. In the pipe joint for preventing the connection pipe from pulling out, the biting member is pressed against the joint body side by contacting the front end surface contacting the joint body, the biting inner surface contacting the outer surface of the connecting tube, and the pressing surface of the nut. Characterized in that the biting member is pressed toward the joint body side by the tightening of the nut to reduce the diameter and the thin-walled cylindrical part is deformed to keep the tightening force on the pipe substantially constant. Pipe fittings.