JP2000230681A - Connecting structure of thin stainless steel pipe to joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connecting structure applicable even to a thin stainless steel pipe having a large diameter by providing a bolt for fixing the flange of a joint body to the flange of a nipping part. SOLUTION: To connecting a thin stainless steel pipe 1, joint body 2, a nipping part 3, a nipping ring 4 and a gasket packing 5, the nipping part 3 from which a packing 10 is removed is fitted onto the stainless steel pipe 1 to form a bulge part 8 at the end of the thin stainless steel pipe 1. Thereafter, the packing 10 is inserted and fitted thereto, and the nipping ring 4 is further fitted to the fitting recessed part 34 of the nipping part 3. Thereafter, the flange 26 of the joint body 2 is connected to the flange 19 of the nipping part 3. At this time, the gasket packing 5 is put between the connecting surface 27 of the flange 26 of the joint body 2 and the connecting surface 39 of the flange 19 of the nipping part 3 and between the flange 26 and the nipping ring 4, and a bolt is inserted to the mounting hole 28 of the flange 26 of the joint body 2 and the mounting hole 31 of the flange 19 of the nipping part 3, and a nut 31 is fastened thereto to fix the joint body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure between a thin-walled stainless steel pipe and a joint which can easily and surely connect the thin-walled stainless steel pipe and a joint on site.

[0002]

2. Description of the Related Art As a prior art of this kind, there is a connection structure disclosed in Japanese Utility Model Publication No. 2-37015 previously proposed by the present applicant. As shown in FIG. 8 which is an overall cross-sectional view of the connection structure and FIG. 9 which is a partially enlarged cross-sectional view of the connection structure, this connection structure includes a thin stainless steel pipe 51, a joint 52,
It is composed of a nut 53 and a packing 54. The thin-walled stainless steel pipe 1 is formed with an annular mountain-shaped projection 57 having two inclined surfaces 55 and 56 by expanding the outer circumference of the end portion. The joint 52 has an inner diameter into which the thin-walled stainless steel pipe 51 is inserted, and a male screw 58 is formed on an outer peripheral surface of an end thereof. A first notch 61 is formed by a tapered portion 59 and a packing fitting portion 60 which are in close contact with each other. The nut 53 includes a fitting portion 62 that is externally fitted to the thin-walled stainless steel pipe 51 at a position opposite to the joint 52 and the angled protrusion 57, and a male screw 5 of the joint 52.
8 and a joint abutting surface 64 formed by a difference in inner diameter between the fitting portion 62 and the female screw portion 63. Projection 5
A second notch 65 is formed so as to be in close contact with the other inclined surface 56 of FIG. The packing 54 is provided between the joint 52 and the thin stainless steel pipe 51, and the nut 5
3 and the male screw 58 of the joint 52 are screwed together and fixed, the one inclined surface 55 of the angled projection 57, the joint contact surface 64 of the nut 53, and the packing fitting portion 60 of the joint 52. Are formed so as to be in close contact with each other. By employing such a structure, the effects described in the publication can be obtained.

[0003]

However, according to the above-mentioned conventional connection structure, the female screw portion 63 of the nut 53 which is screwed with the male screw 58 formed on the outer periphery of the joint 52 must be formed inside. , Said nut 5
3, the overall shape and weight of the connection structure tend to increase, and therefore the overall shape and weight of the connection structure tend to increase. In particular, when the diameter of the thin stainless steel pipe is large,
The shape and weight of the nut 53 are considerably large, and it is difficult to reduce the weight of the connection structure. Further, even when the joint 52 and the nut 53 are forgotten to be tightened, there is also a problem that it is difficult to recognize them only from the outside.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to reduce the shape and weight of the connection structure and reduce the weight so that the thin-walled stainless steel pipe is suitable even when the pipe diameter is large. It is a technical object to provide a connection structure between a stainless steel pipe and a joint, and to provide a connection structure between a thin-walled stainless steel pipe and a joint that can easily recognize, from the outside, forgetting to tighten a connection portion between the thin-walled stainless steel pipe and the joint. It is assumed that.

[0005]

Means for solving the above problems are as follows. That is, the connection structure of a thin stainless steel pipe and a joint according to claim 1 has a thin stainless steel pipe in which a bulged portion having two inclined surfaces is formed on the outer periphery of the end, and a flange portion is formed on the outer periphery of the end. A flange body is formed on the outer periphery of the end of the joint body, and a fitting recess matching the shape of the holding ring is formed on the inner periphery of the end of the joint body, and the thin stainless steel pipe is An inclined pressing surface which is fitted to an end portion and presses one inclined surface of the bulging portion is formed on the inner periphery, and the bulging portion is located at a position opposed to the inclined pressing surface with the bulging portion interposed therebetween. A packing is provided for closely pressing the other inclined surface, and a clamping portion for clamping the bulging portion by the inclined pressing surface and the packing, and a flange portion formed on an outer periphery of an end on the joint body side, and the fitting is formed. The fitting body side end face Together with the joint body side end face of the flange part, the joint face with the flange part of the joint body is formed, and the sandwiching part side end face presses the packing, and the joint face of the joint body flange part with the clamp face. Gasket packing sandwiched between a flange portion of the portion and a joint surface formed by each joint body side end surface of the sandwiching ring,
It has a bolt which fixes a flange part of the above-mentioned joint main part, and a flange part of the above-mentioned holding part.

According to a second aspect of the present invention, in the connection structure of the thin stainless steel tube and the joint, a packing fitting groove is formed on an outer periphery of an end of the holding ring on the side of the holding portion, and the packing fitting groove is provided. A packing is fitted into the fin.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A connection structure between a thin stainless steel pipe and a joint according to an embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1 which is a partially enlarged cross-sectional view of the connection structure, and FIG. 2 which is an overall cross-sectional view of the connection structure, as shown in FIG. It is composed of a main body 2, a holding portion 3, a holding ring 4, and a gasket packing 5.

The thin stainless steel tube 1 has two inclined surfaces 6, 7 formed on the outer periphery of the end by increasing the diameter of the tube.
And an annular bulging portion 8 having the following shape. One of the two inclined surfaces 6, 7 of the bulging portion 8 is pressed by the inclined pressing surface 9 of the holding portion 3, while the other inclined surface 7 is pressed.
Are pressed by the packing 10 and come into close contact with each other. Thus, the bulging portion 8 is sandwiched between the inclined pressing surface 9 and the packing 10. In order to form such a bulging portion 8, a tube expanding device 11 as shown in FIGS. 3 and 4 is used here. In addition, the method for forming the bulging portion 8 is not limited to this, and it goes without saying that another method may be used.

3 and 4, an expansion device 11 includes an expansion head 12 fixed to a base (not shown) and an expansion head 1.
A shaft 13 movably inserted into the shaft 2, a rubber receiving portion 14 fitted externally to the shaft 13, expanded rubber 15 and a rubber presser 16, and a locking portion 1 fixed to the tip of the shaft 13.
7 is a main component.

[0010] The pipe expanding operation is performed as follows. First, as shown in FIG. 3, a flange portion 19 of the clamping portion 3 is joined to a flange portion 18 formed on an outer periphery of an end of the pipe expansion head 12. At this time, the packing 1 of the holding portion 3
0 is removed, and a bolt 20 provided on the flange portion 18 of the pipe expansion head 12 is joined so as to be inserted into a mounting hole 21 provided on the flange portion 19 of the holding portion 3. The nut 22 is screwed and tightened to fix it. At this point, the thin stainless steel pipe 1 is inserted into the shaft 1 from the end.
3. The rubber receiving portion 14, the expanded rubber 15, the rubber presser 16, and the locking portion 17 are inserted at the same time. Then, when the shaft 13 is pulled in the direction of arrow P by a device not shown, the locking portion 17 presses the rubber presser 16 in the direction of arrow P as shown in FIG.
The expanded rubber 15 sandwiched by the rubber retainers 16 and pressed from both sides has its axial width reduced, and expands in the circumferential direction by the reduced volume. As shown in FIG. 3, on the outer periphery of the expanded rubber 15, the inclined pressing surface 9 of the clamping portion 3, the inner peripheral surface 23 of the clamping portion connected to the inclined pressing surface 9, and the tip of the expanding head 12. Trapezoidal space 2 formed by notch 24 formed in the inner peripheral surface
5, the thin-walled stainless steel pipe 1 bulges along the shape of the trapezoidal space 25 at the end thereof along with the circumferential expansion of the expandable rubber 15 and the bulging portion. 8 is formed.

When the bulging portion 8 is formed in this way, the inclination angle of the one inclined surface 6 and the inclination angle of the inclined pressing surface 9 of the holding portion 3 become substantially equal, so that the axis line is one. There is an advantage that the degree of adhesion is improved. Further, since the diameter is expanded by a rubber expansion method in which a uniform force is statically applied to the thin-walled stainless steel pipe 1, the processing can be performed with almost no work hardening and residual stress.

As shown in FIGS. 1 and 2, the joint body 2 has a flange 26 formed on the outer periphery of an end portion thereof. And a joint surface 27 with the holding ring 4. As shown in FIG. 5, the flange 26 is provided with a plurality of mounting holes 28 for joining with the flange 19 of the holding portion 3 arranged in a circle along the flange 26. Here, the mounting hole 28 is a normal circular hole, and the mounting hole 28 of the flange portion 26 of the joint main body 2 and the mounting hole 21 of the flange portion 19 of the clamping portion 3 provided at a position corresponding thereto. The joint main body 2 and the holding portion 3 are joined by inserting a bolt 30 and fastening a nut 31. In some cases, a female screw is formed on the inner peripheral surface of the mounting hole 28 of the flange portion 26 of the joint main body 2. May be provided to join the flange portion 19 of the holding portion 3 only with the bolt 30 without using the nut 31. The shape of the joint main body 2 is not limited to a bent shape as shown in FIG. 2, but may be various shapes such as a T-shape or a linear shape (not shown) as shown in FIG. The inner diameter of the joint body 2 is different at one end and the other end, and the size of the flange portion is also different according to the inner diameter, so that thin stainless steel pipes having different pipe diameters can be connected.

As shown in FIG. 1 and FIG.
Is externally fitted to the end of the thin-walled stainless steel pipe 1. Here, an inclined pressing surface 9 that presses one inclined surface 6 of the bulging portion 8 is formed on the inner periphery of the holding portion 3, and faces the inclined pressing surface 9 with the bulging portion 8 interposed therebetween. Packing 1 pressed against the other inclined surface 7 of the bulging portion 8 at a position where
0 is placed. Therefore, the holding portion 3 holds the bulging portion 8 from both sides by the inclined pressing surface 9 and the packing 10.

The packing 10 is fitted into a packing fitting portion 32 formed of an annular groove having an inner diameter larger than the inner peripheral surface 23 connected to the inclined pressing surface 9.
Here, a side surface of the packing fitting portion 32 opposite to the bulging portion 8 is a holding portion side end surface 33 of the holding ring 4 main body.
Since the holding ring 4 is pressed toward the holding portion 3 by the flange portion 26 of the joint body 2 via the gasket packing 5, the packing 1
0 is fitted into the packing fitting portion 32, and then the holding ring 4 is fitted into the fitting concave portion 34 of the holding portion 3, whereby the packing 10 becomes the holding portion side end surface 33 of the body of the holding ring 4. Is pressed from the side. Thereby, the packing 10 swells in the radial direction to increase the degree of close contact with the other inclined surface 7 of the swelling portion 8, and the packing fitting portion including the holding portion side end face 33 of the holding ring 4. 32 will also be in close contact. The packing 10 is made of an elastic rubber or the like, and has a rectangular ring-shaped cross section. By providing such a packing 10, it is possible to reliably prevent leakage of fluid flowing inside the thin-walled stainless steel pipe 1 and the joint body 2 and intrusion of air from the outside.

A flange portion 19 is formed on the outer periphery of the end of the holding portion 3 on the joint body 2 side. As with the joint body 2, the bolt 30
Are arranged in a circular shape along the flange portion 19, and a plurality of mounting holes 21 are provided at positions corresponding to the mounting holes 28 of the flange portion 26 of the joint body 2.

Further, a fitting recess 34 having a shape matching the shape of the holding ring 4 is formed on the inner periphery of the end of the holding portion 3 on the joint body 2 side. That is, the fitting recess 34 is a recess having a space having substantially the same shape as the holding ring 4, and a stepped portion corresponding to a flange 35 formed on the outer periphery of the end of the holding ring 4 on the joint body side. 36 are provided. By providing the stepped portion 36, when the holding ring 4 is fitted into the fitting concave portion 34, the holding ring 4 does not enter the holding portion 3 side too much,
The packing 10 can be appropriately pressed, and the joint body side end face 37 of the clamping ring 4 and the joint body side end face 38 of the flange 19 of the clamping section 3 are located on the same plane. A joint surface 39 of the main body 2 with the flange 26 is formed.

The holding ring 4 is connected to the joint body 2.
A flange 35 is formed on the outer periphery of the side end. This collar 35
When the holding ring 4 is fitted into the fitting concave portion 34, the end surface on the holding portion side comes into contact with the stepped portion 36, whereby the holding ring 4 is fixed at an appropriate position as described above. Is done. An end surface 33 of the main body of the holding ring 4 on the holding portion side.
Is formed in a planar shape to press the packing 10. Further, the joint body side end face 37 of the clamping ring 4 and the joint body side end face 38 of the flange part 19 of the clamping part 3 constitute a joint surface 39 with the flange part 26 of the joint body 2. Flange part 1 of 3
9 is formed in a plane shape so as to form the same plane as the joint body side end face 38.

A packing fitting groove 40 is formed on the outer periphery of the end of the holding ring 4 on the holding portion 3 side,
A packing 41 is fitted in the packing fitting groove 40. As the packing 41, an O-ring or the like is usually used. By providing the packing 41, the holding ring 4 is not easily disengaged from the state in which the holding ring 4 is fitted in the fitting concave portion 34 of the holding portion 3, so that the joint body 2 and the holding ring 4 after fitting are held. The holding part 3
It is possible to prevent the holding ring 4 from coming off during the connection work with, and to improve workability. Further, the packing 10 of the holding portion 3 can be assisted to prevent leakage of fluid flowing through the thin stainless steel pipe 1 and the inside of the joint body 2 and intrusion of air from outside. The packing 41 may not be provided depending on the specifications of the joint.

The gasket packing 5 is clamped between the joint surface 27 of the flange portion 26 of the joint body 2 and the joint surface 39 formed by the flange portion 19 of the clamping portion 3 and the clamping ring 4. . That is, the gasket packing 5 is connected to the flange 26 of the joint body 2.
And the flange portion 19 of the holding portion 3
And the joint surface 2 on both sides when joined by the nut 31
By being crushed by 7 and 39, airtightness is ensured, and leakage of fluid flowing inside the thin-walled stainless steel pipe 1 and the inside of the joint body 2 and intrusion of air from the outside are prevented. As the gasket packing 5, a gasket whose surface is covered with Teflon is used here, but the gasket packing 5 is not limited to this.

The thin stainless steel pipe 1, the joint body 2, the holding portion 3, the holding ring 4, and the gasket packing 5 having the above-described structure are connected as follows. First, the holding portion 3 from which the packing 10 has been removed.
Is externally fitted to the thin-walled stainless steel pipe 1, and the pipe-expanding operation is performed as described above to expand the pipe diameter at the end of the thin-walled stainless steel pipe 1 to form the bulging portion 8. afterwards,
The packing 10 is inserted and fitted into the packing fitting portion 32 from the end of the holding portion 3 on the joint body 2 side,
Further, the holding ring 4 is fitted into the fitting recess 34 of the holding portion 3. In this state, as shown in FIG.
The holding portion 3 is fitted around the end of the thin stainless steel tube 1, and the bulging portion 8 is held from both sides by the inclined pressing surface 9 of the holding portion 3 and the packing 10.
Since the packing 10 is not pressed by the holding ring 4, the packing 10 is not completely held. Also, the holding body 4 has a joint body side end surface 37 which is formed by the flange portion 19 of the holding portion 3. It is in a state of slightly projecting from the joint body side end face 38.

Thereafter, as shown in FIGS. 1 and 2, the flange 26 of the joint body 2 is joined to the flange 19 of the holding portion 3. At this time, the gasket packing 5
Between the joint surface 27 of the flange portion 26 of the joint body 2 and the joint surface 39 formed by the flange portion 19 of the clamping portion 3 and the clamping ring 4, and mounting the flange portion 26 of the joint body 2. The bolt 30 is inserted through the hole 28 and the mounting hole 21 of the flange portion 19 of the holding portion 3 so that the nut 3
1 is fixed by fastening. As a result, the gasket packing 5 is crushed by the joint surfaces 27 and 39 on both sides, thereby ensuring the airtightness. The gasket packing 5 is held until the joint body-side end face 37 of the clamp ring 4 and the joint body-side end face 38 of the flange portion 19 of the clamp section 3 are located on the same plane.
Is pressed toward the holding portion 3 by the flange portion 26 of the joint body 2. Thereby, the packing 1
0 is pressed from the side by the holding portion side end surface 33 of the holding ring 4 body and swells in the radial direction, so that the degree of adhesion between the swelling portion 8 of the thin stainless steel pipe 1 and the other inclined surface 7 is reduced. As the height becomes higher, the bulging portion 8 can be clamped, and furthermore, the sealing portion is tightly attached to the side surface of the packing fitting portion 32 including the clamping portion side end surface 33 of the clamping ring 4.

[0022]

As described above, according to the first aspect of the present invention,
Has the following effects. That is, since the method of joining the flanges with small bolts and nuts is adopted instead of the conventional method using large nuts, the connection structure can be reduced in size and weight. Therefore, the thin stainless steel pipe can be made suitable even when the pipe diameter is large. In addition, the thin stainless steel pipe and the holding section are firmly connected by holding the bulging portion formed on the outer periphery of the end of the thin stainless steel pipe by the inclined pressing surface of the holding section and the packing pressed by the holding ring. In addition to the above, it is possible to secure high sealing performance and to reliably prevent leakage of fluid flowing through the thin-walled stainless steel pipe and the inside of the joint body and intrusion of air from outside. Furthermore, the tightening state can be easily confirmed by the width of the gap between the flange portion of the joint body and the flange portion of the holding portion, and the flange portion of the joint body and the flange portion of the holding portion are fixed. Since the bolts to be exposed are exposed, the tightened state of the bolts can be easily checked, so that forgetting to tighten can be prevented.

According to a second aspect of the present invention, there is provided a connecting structure for a thin-walled stainless steel pipe and a joint, in addition to the effect of the first aspect of the present invention, in a state where the holding ring is fitted into the fitting recess of the holding portion. Since it does not easily come off, it is possible to prevent the holding ring from coming off during the connection work between the joint body and the holding portion fitted with the holding ring, and to enhance workability. Further, there is an effect that the packing of the holding portion is assisted to prevent leakage of fluid flowing inside the thin-walled stainless steel pipe and the inside of the joint body and intrusion of air from outside.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of a connection structure according to an embodiment of the present invention.

FIG. 2 is an overall sectional view of a connection structure according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state before pipe expansion by a pipe expansion device for forming a bulging portion.

FIG. 4 is a cross-sectional view showing a state after pipe expansion by a pipe expansion device for forming a bulging portion.

FIG. 5 is a side view showing a joint main body of the connection structure according to the embodiment of the present invention.

FIG. 6 is an overall cross-sectional view showing a case where the joint body has a T-shape in the connection structure according to the embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a state before connecting the joint body in the connection structure according to the embodiment of the present invention.

FIG. 8 is an overall sectional view of a connection structure according to a conventional example.

FIG. 9 is a partially enlarged sectional view of a connection structure according to a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Thin-walled stainless steel pipe 2 Joint main body 3 Nipping part 4 Nipping ring 5 Gasket packing 6 One inclined surface of the bulging part 7 The other sloping surface of the bulging part 8 Swelling part 9 Slant pressing surface 10 Packing 11 Expansion part 19 Nipping part 26 Flange part of the joint body 27 Joint surface of the flange part of the joint body 30 Bolt 31 Nut 32 Packing fitting part 33 End face on the holding part side of the holding ring 34 Fitting recess 35 Flange of the holding ring 37 Joint body of the holding ring Side end face 38 Joint body side end face of the flange portion of the holding portion 39 Joint surface formed by the flange portion of the holding portion and the holding ring 40 Packing fitting groove of the holding ring 41 Packing of the holding ring

Claims (2)

[Claims] 1. A thin-walled stainless steel pipe having a bulged portion having two inclined surfaces formed on an outer periphery of an end portion, a joint body having a flange portion formed on an outer periphery of the end portion, and an outer periphery of an end portion on the joint body side. A flange is formed at the end of the joint body side, a fitting concave portion conforming to the shape of the holding ring is formed at the inner periphery of the end of the joint body, and the flange is externally fitted to the end of the thin stainless steel pipe, and the bulge is formed at the inner periphery. An inclined pressing surface that presses one inclined surface of the portion is formed, and a packing that presses the other inclined surface of the bulging portion in close contact with the inclined pressing surface across the bulging portion is disposed. A clamping portion for clamping the bulging portion by the inclined pressing surface and the packing; and a flange portion formed on an outer periphery of an end portion on the joint body side; the fitting portion is fitted into the fitting concave portion; Together with the joint body side end face of the flange portion, A clamping surface which forms a joint surface with the flange portion, and a clamping portion side end face of which presses the packing; a coupling surface of the flange portion of the joint body, the flange portion of the clamping portion and the joint body side of the clamping ring; A thin-walled stainless steel pipe and a joint, comprising: a gasket packing sandwiched between a joint surface constituted by an end face; and a bolt for fixing a flange portion of the joint body and a flange portion of the clamp portion. Connection structure. 2. The thin-walled stainless steel pipe and joint according to claim 1, wherein a packing fitting groove is formed on an outer periphery of an end portion of the holding ring on the holding portion side, and packing is fitted into the packing fitting groove. Connection structure.