JP2016142293A - Connection mechanism of thin wall stainless steel pipe and joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce frictional resistance between a nut and a thin wall stainless steel pipe, in connecting the thin wall stainless steel pipe and a joint with the nut.SOLUTION: In a connection mechanism of a thin wall stainless steel pipe and a joint, a nut 3 is screwed into a joint 2 while contacting with one inclination surface 5 of a crest type projection part 7 of a thin wall stainless steel pipe 1, and forms a convex part 15b in a second cutout part 15, and thereby the contact part of the nut 3 with the one inclination surface 5 of the crest type projection part 7 is formed such a shape that linearly contacts with the one inclination surface 5 of the crest type projection part 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a connection mechanism between a thin stainless steel pipe and a joint, which can easily and reliably connect a thin stainless steel pipe and a joint on site, and can smoothly perform nut screwing.

As a conventional connection mechanism between a thin-walled stainless steel pipe and a joint, there is a connection mechanism disclosed in Patent Document 1 previously proposed by the present applicant.
As shown in FIG. 10, this connection mechanism includes a thin stainless steel pipe 1, a joint 2, a nut 3, and a packing 4. And the edge part 1a side is accommodated in the inside 2a of the joint 2 from the angle-shaped projection part 7 which has the two inclined surfaces 5 and 6 which expanded the outer periphery of the edge part of the thin-walled stainless steel pipe 1 outside in the shape of a mountain, and the angle The joint 2 is brought into contact with one inclined surface 6 on the end 1a side of the protruding portion 7 directly or via the packing 4, and the nut 3 is brought into contact with the other inclined surface 5 of the mountain-shaped protruding portion 7. A connection mechanism between the thin stainless steel pipe 1 and the joint 2 for connecting the thin stainless steel pipe 1 and the joint 2 by screwing and fixing the joint 2 and the nut 3, and two inclinations of the thin stainless steel pipe 1 The outer peripheral surface 1b on the side of the end 1a with respect to the mountain-shaped protrusion 7 having the surfaces 5 and 6 is reduced in diameter so as to be tapered, and the end portion inner peripheral surface 2c of the joint 2 is extended from the end edge to the inside. Formed at the end of the thin stainless steel tube 1 It is obtained by forming a tapered inclined surface so as to be in close contact with the tapered outer peripheral surface 1b of the tapered was.

  By adopting such a connection mechanism, it is easy to insert the end portion 1a side of the thin stainless steel pipe 1 into the interior 2a of the joint 2 during assembly, and the work efficiency is improved as it is. However, after insertion, the outer peripheral surface 1b of the thin stainless steel pipe 1 and the inner peripheral surface 2c of the joint 2 are in close contact with each other, so that the fluid inside the joint 2 can be prevented from entering the packing 4 direction. Further, since this blocking force becomes stronger as the thin stainless steel pipe 1 is pushed into the joint 2 more strongly, there is an advantage that it can be performed simultaneously in the process of assembling the connecting mechanism for screwing and fixing the nut 3 and the joint 2 together.

JP 2014-185675 A

  However, according to the above prior art, the work efficiency at the time of assembling is improved, and it is possible to prevent the fluid from entering the packing 4 by screwing the nut 3 at the time of assembling. However, as shown in FIG. At the time of screwing, the inclined surface (second notch portion 15) of the nut 3 and the inclined surface 5 of the mountain-shaped projection 7 are brought into surface contact, and the frictional resistance is large. Therefore, there is a possibility that the nut 3 cannot be smoothly screwed, and there is room for improvement in that respect.

  In view of the above circumstances, the present invention is to smoothly screw the nut, and the feature thereof is a mountain having two inclined surfaces in which the outer periphery of the end of the thin stainless steel pipe is expanded outward in a mountain shape. The end side of the mold protrusion is housed in the joint, and the joint is brought into contact with one inclined surface on the end side of the angle protrusion directly or through packing, and the other end of the angle protrusion is In the connection mechanism between the thin stainless steel pipe and the joint, the two slopes of the thin stainless steel pipe are connected to each other by bringing the nut into contact with the inclined surface and screwing and fixing the joint and the nut. The diameter of the outer peripheral surface on the end side of the angled protrusion having a surface is reduced so as to be tapered, and the end of the thin stainless steel pipe is directed from the end edge to the inside on the inner peripheral surface of the end of the joint. A tapered inclined surface is formed so as to be in close contact with the tapered outer peripheral surface formed in the above, and the nut is screwed into the joint while being in contact with the other inclined surface of the mountain-shaped protrusion, A thin-walled stainless steel pipe characterized in that a contact portion of the nut with the other inclined surface of the chevron-shaped protrusion is formed into a line contact or point contact with the other inclined surface of the chevron-shaped protrusion. And the joint connection mechanism.

  According to the present invention, the nut is screwed into the joint while being in contact with the other inclined surface of the thin-walled stainless steel pipe, and the contact portion of the nut with the other inclined surface of the thin-walled stainless steel tube is in line contact with the inclined surface or By forming a point contact shape, the frictional resistance between the nut and the thin stainless steel pipe can be reduced. Therefore, the nut can be smoothly screwed into the joint, and the work efficiency during assembly can be further improved.

In the figure of Embodiment 1 of the present invention, (a) is an upper cross-sectional side view, the right half is a state in which the nut is loosened, and the left half is a state in which the nut is tightened, (b) is an arrow in (a) The enlarged view of the part of A. FIG. The upper part expanded sectional view of the nut of FIG. The exploded view which abbreviate | omitted a part of connection mechanism of FIG. 1, and the schematic perspective view of one member extracted from it. Sectional drawing which shows the state which attached the nut and thin-walled stainless steel pipe to the pipe expansion apparatus in order to form the mountain-shaped projection part of the end part of a thin-walled stainless steel pipe, (b) is an expanded sectional view of the part of the arrow B of (a) . It is sectional drawing which shows the state which the force to the arrow P direction produced | generated from the state of FIG. 4, and expanded, (b) is an expanded sectional view of the part of the arrow C of (a). In the upper section side view of Embodiment 2 of the present invention, the right half loosens the nut and the left half tightens the nut. FIG. 7 is a cross-sectional view taken along the line YY in FIG. 6, with a part enlarged and showing a thin stainless steel pipe omitted. In the upper cross section side view of Embodiment 3 of the present invention, the right half loosens the nut and the left half tightens the nut. It is the perspective view of the nut of the connection mechanism of FIG. 8, and the figure which expanded a part. It is a figure of the embodiment of a prior art example, (a) is an upper cross-sectional side view, the right half is the state which loosened the nut, the left half is the state which tightened the nut, (b) is the arrow A of (a). The enlarged view of the part.

The best mode of the present invention will be described. Note that the same constituent elements as those in the prior art will be described using the same symbols.
(Embodiment 1)
As shown in FIGS. 1 and 3, the thin stainless steel pipe 1 is formed with a mountain-shaped protrusion 7 having two inclined surfaces 5 and 6 on the outer periphery of the end. The joint 2 has an inner diameter for inserting the thin-walled stainless steel pipe 1 into the interior 2a, and a male thread 8 is formed on the outer peripheral surface 2b of the narrow end, and the angle protrusion is formed on the inner periphery of the end. A first cutout portion 11 is formed which includes a corner portion 9 that abuts on one inclined surface 6 on the end portion 7 side and a packing fitting portion 10. The nut 3 includes a fitting portion 12 that externally fits the thin stainless steel pipe 1 facing the joint 2 with the mountain-shaped protrusion 7 as a boundary, and a female screw portion 13 that is screwed into the male screw 8 of the joint 2. And a joint contact surface 14 formed by the inner diameter difference between the fitting portion 12 and the female screw portion 13, and the other inclined surface of the mountain-shaped protrusion 7 is formed at the inner end portion of the fitting portion 12. A second cutout portion 15 that contacts 5 is formed. A plurality of annular grooves 15a are formed in the second cutout portion 15 along the circumferential direction, whereby a plurality of annular protrusions 15b are formed so as to protrude inward. ing. As for each convex part 15b, the internal peripheral surface is formed in cross-sectional arc shape. In this embodiment, the groove 15a and the convex portion 15b are also formed at the end portion of the fitting portion 12 on the second notch portion 15 side. The packing 4 is fitted between the joint 2 and the thin stainless steel pipe 1, and when the female thread 13 of the nut 3 and the male thread 8 of the joint 2 are screwed and fixed, The inclined surface 6, the joint abutting surface 14 of the nut 3, and the packing fitting portion 10 of the joint 2 are formed in close contact with each other.

  In addition, the corner portion 9 acts to push the lower portion of the packing 4 along the inclined surface 6, or penetrates into the surface of the inclined surface 6 while pushing the packing 4, so that the fluid enters the packing 4. May be blocked together with the packing 4.

  Next, the outer peripheral surface of the end edge of the thin stainless steel tube 1 on the end side from the mountain-shaped protrusion 7 is tapered to form a tapered outer peripheral surface 1b. Further, the inner peripheral surface of the joint 2 from the corner portion 9 forming the first notch portion 11 of the joint 2 toward the inner side 2a is also a tapered inner peripheral surface 2c formed in a tapered shape. The tapered outer peripheral surface 1b of the thin stainless steel pipe 1 and the tapered inner peripheral surface 2c of the joint 2 are in close contact with each other.

  In the connection mechanism of this embodiment, a thin cylindrical ring member 26 is used. The ring member 26 has an outer diameter corresponding to the diameter of the inner portion 2 a of the joint 2, and has a thickness substantially the same as the thickness of the thin stainless steel pipe 1. The length of the ring member 26 in the axial direction is substantially the same as the distance between the thin stainless steel pipes 1 and 1 when the thin stainless steel pipes 1 and 1 are connected to both sides of the joint 2. As shown in FIG. 1, in a state where the thin stainless steel pipes 1, 1 are connected to both sides of the joint 2, the ring member 26 has the thin stainless steel pipes 1, 1 on both sides so that the axial direction is along the horizontal direction. It is arranged in between and provided in the interior 2 a of the joint 2.

  The diameter of the thin stainless steel pipe 1 can be reduced at the same time when the mountain-shaped protrusion 7 is expanded using a pipe expanding apparatus as in the prior art. This will be described with reference to FIGS.

  The tube expansion device 16 includes a tube expansion head 17 fixed to a base (not shown), a shaft 18 that is movably inserted into the tube expansion head 17, a rubber receiver 19 that is externally fitted to the shaft 18, a tube expansion rubber 20, and rubber. The presser 21 and the locking portion 22 fixed to the tip of the shaft 18 are the main components.

  And the tube expansion operation is performed as follows. First, as shown in FIG. 4, a male screw 23 formed on the outer periphery of the pipe expansion head 17 and a female screw of a female screw portion 13 of a nut 3 fitted on the thin stainless steel pipe 1 are screwed and fixed. At this time, the shaft 18, the rubber receiver 19, the expanded rubber 20, the rubber retainer 21, and the locking portion 22 are simultaneously inserted from the end of the thin stainless steel pipe 1. When the shaft 18 is pulled in the direction of arrow P by a device not shown in the drawing, the locking portion 22 presses the rubber presser 21 in the direction of arrow P as shown in FIG. The expanded rubber 20 sandwiched between the rubber retainers 21 and pressed from both sides is reduced in its axial width, and expands in the circumferential direction by the reduced volume. On the outer periphery of the expanded tube expansion rubber 20, there is a mountain-shaped space formed by the second notch 15 of the nut 3 and the notch 24 formed on the inner peripheral surface of the tip of the tube expansion head 17. As the pipe expansion rubber 20 expands in the circumferential direction, the thin stainless steel pipe 1 has a notch 24 formed at the end of the second notch 15 of the nut 3 and the tip inner peripheral surface of the pipe expansion head 17 at its end. Ridges 7 are formed.

  A gap X greater than the thickness of the thin stainless steel tube 1 is formed between the inner peripheral surface of the tube expanding head 17 where the tip of the thin stainless steel tube 1 is located and the outer peripheral surface of the rubber receiver 19. As a result, as shown in FIG. 5, when the pressure of the expanded rubber 20 is applied at the time of expansion, the edge of the thin stainless steel tube 1 is tapered inward so that the edge of the thin stainless steel tube 1 bends toward the rubber receiver 19 and becomes tapered. The diameter is reduced.

  In this way, when the pipe expansion is completed, the internal thread of the female thread portion 13 of the nut 3 and the male thread 23 of the pipe expansion head 17 are unscrewed, and the shaft 18 is simply pulled out of the thin stainless steel pipe 1. The nut 3 that has been unscrewed is used for connection with the joint 2 as it is.

  In addition, the diameter reduction of the outer periphery of the thin-walled stainless steel pipe 1 can be performed by other means without using such a pipe expanding apparatus. For example, the outer periphery of the edge of the thin-walled stainless steel pipe 1 may be cut into a taper shape by cutting with an abrasive. In this case, the inner diameter of the thin-walled stainless steel pipe 1 is not reduced, so that it does not affect the fluid passage amount.

The thin stainless steel pipe 1, the joint 2, the nut 3, and the packing 4 configured as described above constitute a connection mechanism as follows.
First, as shown in FIG. 1B, the packing 4 is fitted into the packing fitting portion 10 of the joint 2. Thereafter, the end 1a of the thin stainless steel pipe 1 is inserted into the interior 2a of the joint 2, but the end 1a is tapered and easily enters the interior 2a of the joint 2 due to taper. Next, the male screw 8 formed on the outer peripheral surface 2 b of the end portion of the joint 2 and the female screw of the female screw portion 13 formed on the inner peripheral surface of the nut 3 are screwed together, and the joint contact surface 14 of the nut 3 is engaged. Is screwed in until it comes into contact with the front end surface 2d of the joint 2. As a result, the angled projection 7 of the thin stainless steel pipe 1 is sandwiched and fixed from both sides by the corner 9 of the joint 2 and the packing 4 and the second notch 15 of the nut 3.
At the time of such assembly, since the outer peripheral surface 1b of the end 1a of the thin stainless steel pipe 1 is reduced in diameter, the insertion into the joint 2 is facilitated, and the work efficiency is improved.

  Moreover, among the inner peripheral surface 2a of the joint 2, the end inner peripheral surface 2c is formed in a tapered shape with the same angle as the outer peripheral surface 1b of the end portion 1a of the thin stainless steel tube 1, so Since the peripheral surfaces are brought into close contact with each other, there is no gap, and almost no leakage of fluid flowing in the interior 2a to the packing 4 side occurs.

  Further, when assembling, the nut 3 is screwed into the joint 2 while being in contact with the inclined surface 5 of the thin-walled stainless steel pipe 1. By forming the convex portion 15 b in the second notch portion 15 of the nut 3, the contact portion of the nut 3 with the inclined surface 5 of the thin stainless steel pipe 1 is formed in a shape in line contact with the inclined surface 5. Thereby, when screwing the nut 3 to the joint 2, the frictional resistance between the nut 3 and the thin stainless steel pipe 1 can be reduced. Therefore, the nut 3 can be smoothly screwed to the joint 2 and the work efficiency during assembly can be further improved.

  Furthermore, by using the ring member 26, the thin stainless steel pipes 1 and 1 arranged on both sides can be smoothly connected. Thereby, in the connection location of the thin stainless steel pipes 1 and 1 on both sides, the disturbance of the fluid flow can be reduced, and the fluid can flow smoothly.

  In FIG. 1, reference numeral 25 denotes a dish washer interposed between the opposing outer peripheral side surfaces of the nut 3 and the joint 2, and the dish washer 25 that was visible from the outside as before tightening on the right side of FIG. 1. As shown in FIG. 1, the colored surface 25a is not visible from the outside because the inclination angle of the dish washer 25 stands in the vertical direction, after the nut 3 is tightened into the left joint 2 in FIG. As a result, it is possible to visually confirm that the screwing and fixing of the nut 3 and the joint 2 have been completed. At the same time, there is an advantage that loosening of the joint 2 and the nut 3 can be prevented by the reaction force of the dish washer 25.

(Embodiment 2)
Next, Embodiment 2 of the connection mechanism between the thin stainless steel pipe and the joint according to the present invention will be described with reference to FIGS. The connection mechanism between the thin stainless steel pipe and the joint according to the second embodiment is basically the same as the connection mechanism between the thin stainless steel pipe and the joint according to the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the first embodiment, the annular notch 15b is formed in the second notch 15 of the nut 3 along the circumferential direction so that the nut 3 and the thin stainless steel pipe 1 are in line contact. In the second embodiment, a plate-like protrusion 27 is formed in the second notch 15 of the nut 3. Specifically, as shown in FIG. 6, the protrusion 27 is erected integrally with the second cutout portion 15 so that the plate surface extends in the left-right direction, and they are mutually circumferential and the like. They are formed radially at intervals. The inner surface of each protrusion 27 is formed in a substantially arc shape in cross section.

  According to the connection mechanism between the thin stainless steel pipe and the joint according to the second embodiment, the protrusion 27 is formed in the second notch 15 of the nut 3 so that the nut 3 contacts the inclined surface 5 of the thin stainless steel pipe 1. The part is formed in a shape in line contact with the inclined surface 5. Thereby, when screwing the nut 3 to the joint 2, the frictional resistance between the nut 3 and the thin stainless steel pipe 1 can be reduced.

(Embodiment 3)
Next, Embodiment 3 of the connection mechanism between the thin stainless steel pipe and the joint according to the present invention will be described with reference to FIGS. The connection mechanism between the thin stainless steel pipe and the joint according to the third embodiment is basically the same as the connection mechanism between the thin stainless steel pipe and the joint according to the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the first embodiment, the annular notch 15b is formed in the second notch 15 of the nut 3 along the circumferential direction so that the nut 3 and the thin stainless steel pipe 1 are in line contact. In the third embodiment, the nut 3 and the thin stainless steel pipe 1 are configured to be in point contact. Specifically, a plurality of substantially columnar protrusions 28 are formed in the second notch 15 of the nut 3 so as to protrude inward. A plurality of protrusions 28 are formed in the second notch 15 so as to be spaced apart from each other along the left-right direction, and are formed radially at equal intervals in the circumferential direction. The tip of each projection 28 is formed in a substantially hemispherical shape.

  According to the connection mechanism between the thin stainless steel pipe and the joint according to the third embodiment, the protrusion 28 is formed in the second notch 15 of the nut 3 so that the contact with the inclined surface 5 of the thin stainless steel pipe 1 of the nut 3 is achieved. The part is formed in a shape that makes point contact with the inclined surface 5. Thereby, when screwing the nut 3 in the joint 2, the frictional resistance between the nut 3 and the thin stainless steel pipe 1 can be further reduced.

  As described above, the connection mechanism between the thin stainless steel pipe and the joint according to the present invention has a reduced diameter on the outer periphery of the end edge located on the end side from the mountain-shaped protrusion of the thin stainless steel pipe. When the steel pipe and the joint are assembled and connected, the end of the thin stainless steel pipe can be easily inserted into the inner hole of the joint, so that the work efficiency is improved and the outer periphery of the end 1a of the thin stainless steel pipe 1 is improved. Since the surface 1b and the inner peripheral surface 2c of the end of the joint 2 are in close contact with each other, there is no gap between them, and almost no fluid leaks to the packing 4, so that it is difficult for the packing 4 to contact the fluid. The life of the packing 4 is extended. In addition, since the contact portion of the nut with the inclined surface of the thin stainless steel pipe is formed in a shape that makes line contact or point contact with the inclined surface, the friction between the nut and the thin stainless steel pipe is caused when the nut is screwed into the joint. Resistance can be reduced. Thereby, a nut can be smoothly screwed together with a joint, and the work efficiency at the time of an assembly can be improved more.

  The connection mechanism between the thin stainless steel pipe and the joint of the present invention is not limited to the configuration of each of the embodiments described above, and can be changed as appropriate. For example, in each of the above embodiments, the protrusion 15b, the protrusion 27, or the protrusion 28 is formed in the second notch 15 of the nut 3. However, the present invention is not limited to this, and the thin stainless steel pipe of the nut 3 is not limited thereto. It is sufficient that the contact portion with one inclined surface 5 has a shape that makes line contact or point contact with the inclined surface 5. Moreover, the number of the convex part 15b, the protrusion part 27, and the protrusion part 28 can be changed suitably.

  It can be effectively used for all buildings such as various buildings, apartment buildings, and general houses that require piping of thin-walled stainless steel pipes for fluids such as tap water.

DESCRIPTION OF SYMBOLS 1 Thin stainless steel pipe 2 Joint 3 Nut 4 Packing 5 Inclined surface 6 Inclined surface 7 Angle-shaped projection part 8 Male screw 9 Corner | angular part 10 Packing insertion part 11 1st notch part 12 Fitting part 13 Female thread part 14 Joint contact surface 15 2nd Notch 15b Convex 27 Protrusion 28 Protrusion

Claims (1)

The end side of the thin stainless steel pipe is accommodated in the joint from the angled protrusion having two inclined surfaces that are expanded outwardly in the shape of a mountain, and one inclination on the edge side of the angled protrusion is A thin stainless steel pipe by bringing a joint into contact with the surface directly or via a packing, bringing a nut into contact with the other inclined surface of the angled projection, and screwing and fixing the joint and the nut In the connection mechanism between the thin stainless steel pipe connecting the joint and the joint,
The outer peripheral surface of the thin-walled stainless steel pipe is tapered so that the outer peripheral surface on the end side is tapered so as to be tapered, and the end inner peripheral surface of the joint extends from the end edge to the inside. A tapered inclined surface is formed so as to be in close contact with the tapered tapered outer peripheral surface formed at the end of the thin stainless steel pipe,
The nut is screwed into the joint while being in contact with the other inclined surface of the mountain-shaped protrusion, and the contact portion of the nut with the other inclined surface of the mountain-shaped protrusion is defined as the mountain-shaped protrusion. A thin-walled stainless steel pipe-joint connection mechanism characterized in that it is formed in a shape that makes line contact or point contact with the other inclined surface of the part.

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