JP7017233B2 - Thin-walled stainless steel pipe expansion device - Google Patents

Description

The present invention relates to a thin-walled stainless steel pipe expanding device for expanding a thin-walled stainless steel pipe in order to form a mountain-shaped convex portion along the outer peripheral surface of the end portion of the thin-walled stainless steel pipe, and is particularly large when connecting the expanded thin-walled stainless steel pipe to a joint. The present invention relates to a pipe expanding device that can expand a pipe to a mountain-shaped convex portion that can be performed without requiring force.

Regarding the thin-walled stainless steel pipe expanding device, Patent Documents 1 to 3, which are the thin-walled stainless steel pipe expanding devices previously proposed by the applicant, are already known. What is common to these three inventions is to form a mountain-shaped convex portion disclosed in Patent Document 1, in which Patent Document 2 and Patent Document 3 are involved in the improvement of Patent Document 1, and Patent Document 2 among them is related to the improvement of Patent Document 1. When connecting a thin-walled stainless steel pipe, which is a thin-walled stainless steel pipe, to the joint, the tip of the thin-walled stainless steel pipe can be easily fitted into the inner hole of the main body of the joint, making the connection work easy. Further, Patent Document 3 is a pipe expansion device for improving durability by blocking the action of an outward force at the time of pipe expansion so that the pipe expansion member is less likely to be distorted.

By detachably fixing nuts and joints that also serve as pipe expansion rings from both sides of the inclined surface of the chevron convex portion formed by expanding the thin-walled stainless steel pipe by such conventional technology, the thin-walled stainless steel pipe and the joint are firmly strengthened. Moreover, it is possible to obtain a connection mechanism that is hard to disconnect and connects.

Special Publication No. 64-137 Japanese Patent No. 3467545 Japanese Patent No. 541624

However, when the nut that also serves as the pipe expansion ring and the joint are screwed and tightened, the contact between the nut and the inclined surface of the chevron convex portion is surface contact, so friction increases and a large force is required for tightening. , Was a factor that made workers tired. The present invention has been invented for the purpose of a pipe expansion device capable of reducing the contact area between the inclined surface of the mountain-shaped convex portion and the nut that also serves as the pipe expansion ring by reducing such frictional force. Further, during tightening, the thin-walled stainless steel pipe rotates together with the nut that is tightened and rotated on one inclined surface of the mountain-shaped convex portion, so that the thin-walled stainless steel pipe is in close contact with the other inclined surface of the mountain-shaped convex portion. It was invented for the purpose of a pipe expansion device capable of preventing the packing from being worn.

In the present invention for solving the above problems, an fitting inner hole into which a thin-walled stainless steel pipe is internally fitted, and a first dish-shaped tapered portion formed in front of the fitting inner hole and inclined so that the front is expanded in diameter are provided. A chevron shape is formed continuously with the expanding tube head, a fitting hole that is detachably fixed to the front outer periphery of the expanding tube head and in which the thin-walled stainless steel pipe is fitted, and the first dish-shaped tapered portion. A pipe expansion ring having a second dish-shaped tapered portion whose front diameter is reduced and inclined, a guide ring arranged inside the fitting inner hole in the radial direction, and a guide ring into which the thin-walled stainless steel pipe is externally fitted, and the pipe expansion head. A pressure rod inserted into a rod insertion hole opened in the center and having a rear end connected to a pressurizing device, a pipe expansion rubber externally fitted in front of the guide ring in the pressurizing rod, and the pressurization. In a thin-walled stainless steel pipe expanding device having a rubber holding portion formed in front of the pipe expanding rubber in the rod.
It is an object of the present invention to be a thin-walled stainless steel pipe expanding device characterized in that one protrusion or one recess is arranged on a plurality of concentric circles having different diameters on the tapered surface of the second dish-type tapered portion .

The tube expansion head has a male threaded portion formed on the outer peripheral surface of the front portion thereof, and the tube expansion ring has a female threaded portion formed on the inner peripheral surface of the rear portion thereof. The ring is detachably fixed to the expansion head.

The tube expansion head has a fitting convex portion formed on the outer peripheral surface of the front portion thereof, and the tube expansion ring has a fitting concave portion formed on the inner peripheral surface of the rear portion thereof, and the fitting convex portion and the fitting concave portion are fitted. By doing so, the tube expansion ring is detachably fixed to the tube expansion head.

The plurality of protrusions or recesses are distributed on the tapered surface having the center angles of the second dish-shaped tapered portions substantially equal to each other.

The protrusion is a granular protrusion.

A protruding portion or a recessed portion is formed on the surface of the first dish-shaped tapered portion.

The protruding portion or the recessed portion has a rod-like shape or an elongated groove shape that protrudes radially from the center of the first dish-shaped tapered portion in the outer peripheral direction.

According to the present invention, a plurality of protrusions or recesses are formed on the tapered surface of the second dish-shaped tapered portion of the pipe expansion ring forming the inclined surface of the expanded portion of the mountain-shaped convex portion of the thin-walled stainless steel pipe. Since the thin-walled stainless steel pipes in contact with the protrusions are distributed and arranged, the portion of the thin-walled stainless steel pipe that abuts on the protrusions is pressed by the tube-expanding rubber to form a dent, or the portion of the thin-walled stainless steel pipe that abuts on the dents is expanded. Pressed by the rubber to form a bulge. These actions form a gentle depression or bulge on the inclined surface. When connecting a thin-walled stainless steel pipe to a joint, the contact area between the inclined surface of the expansion portion of the chevron convex portion of the thin-walled stainless steel pipe and the tapered surface of the second dish-type tapered portion of the expansion ring, which is also a nut, is small due to this dent or bulge. Therefore, it is possible to obtain a pipe expansion device in which the frictional resistance is reduced by that amount and the labor for rotating the pipe expansion ring can be reduced. Since the protrusions or recesses are arranged one by one on a plurality of concentric circles having different diameters on the tapered surface of the second dish-shaped tapered portion, the concentric circles on the inclined surface of the chevron convex portion of the corresponding thin-walled stainless steel pipe. Since there is only one dent or bulge on the top, even when tightening the nut, which is the expansion ring when connecting, these mesh only once per rotation, and the poles at the final stage of tightening. Except for a slight angle, even if it meshes, it can overcome and rotate, and frictional resistance can be reduced. When the meshing at the final stage is reached, stopping the tightening rotation at that point helps prevent loosening.

The tube expansion head has a male threaded portion formed on the outer peripheral surface of the front portion thereof, and the tube expansion ring has a female threaded portion formed on the inner peripheral surface of the rear portion thereof. Since the ring is detachably fixed to the expansion head, it can be attached to and detached from the expansion head by rotating the expansion ring.

Further, when the structure is such that the fitting convex portion of the pipe expansion head and the fitting concave portion of the pipe expansion ring are fitted and fixed detachably, a protrusion or a recess is formed on the tapered surface of the second dish type taper portion. Since the expansion ring with a portion can be removed and a nut having a tapered surface of another second dish type taper portion can be used, it can be used repeatedly, and is formed on the inclined surface of the expansion portion of the thin-walled stainless steel pipe. Since the tapered surface of the second dish-type tapered portion that does not mesh with the dent or bulge, for example, a flat surface, a dent or a bulge, can be made, the frictional resistance can be further reduced.

When the protrusions or recesses are provided at positions where the center angles on the tapered surface of the second dish-shaped tapered portion are approximately equal, the distance between the tapered surface of the nut and the inclined surface of the mountain-shaped convex portion is averaged. It can be formed evenly.

When the protrusion is a granular protrusion, the contact with the tapered surface at the time of tightening is a point contact, so that the tube expansion device can obtain a connection mechanism having a small frictional force.

When a protrusion or a recess is formed on the surface of the first dish-type tapered portion, a corresponding recess or protrusion is also formed on the inclined surface of the mountain-shaped convex portion of the corresponding thin-walled stainless steel pipe. , The packing may be involved in this dent or protrusion at the time of connection to prevent the rotational force generated in the thin stainless steel pipe.

When the protruding portion or the recessed portion is formed radially from the center to the outer peripheral direction, it is possible to obtain a pipe expanding device which is a connecting mechanism capable of more strongly blocking the rotational force generated in the thin-walled stainless steel pipe at the time of connection.

It is a thin-walled stainless steel pipe expanding device according to the first embodiment of the present invention. (A) It is a cross-sectional view which shows the state before the tube expansion. (B) It is a cross-sectional view which shows the state at the time of tube expansion. It is a perspective view which disassembled and illustrated each component of the tube expansion apparatus of the thin-walled stainless steel pipe which concerns on 1st Embodiment of this invention. It is a thin-walled stainless steel pipe expanding device according to the second embodiment of the present invention. (A) It is an enlarged cross-sectional view of a main part before expansion of a pipe. (B) It is a front view which shows the tube expansion ring. It is a front view of the tube expansion ring (also used as a nut) of the tube expansion device of the thin-walled stainless steel pipe according to the first embodiment of the present invention. (A1) FIG. 4 is a cross-sectional view taken along line XX of FIG. 4 in which a protrusion is provided on the tapered surface of the second dish-shaped tapered portion of the tube expansion ring. (A2) It is sectional drawing of the P part of FIG. 5 (a1) when the thin-walled stainless steel pipe is pressed by the tube expansion rubber and expanded. (B1) FIG. 4 is a cross-sectional view taken along line XX of FIG. 4 in which a recess is provided on the tapered surface of the second dish-shaped tapered portion of the tube expansion ring. (B2) It is sectional drawing of the Q part of FIG. 5 (b1) when the thin-walled stainless steel pipe is pressed by the tube expansion rubber and expanded. It is a front view of the tube expansion head of the tube expansion device of the thin-walled stainless steel pipe according to the first embodiment of the present invention. (A1) FIG. 6 is a sectional view taken along line YY of FIG. 6 in which a protruding portion is provided on the tapered surface of the first dish-shaped tapered portion of the tube expansion head. (A2) It is a cross-sectional enlarged explanatory view of the R part of FIG. 7 (a1) when the thin-walled stainless steel pipe is pressed by the tube expansion rubber and expanded. (B1) FIG. 6 is a cross-sectional view taken along the line YY of FIG. 6 in which a recess is provided on the tapered surface of the first dish-type tapered portion of the tube expansion head. (B2) FIG. 6 is an enlarged cross-sectional explanatory view of a portion S in FIG. 7 (b1) when a thin-walled stainless steel pipe is pressed by a tube-expanding rubber and expanded. (A) It is sectional drawing for demonstrating the connection structure of the thin-walled stainless steel pipe expanded by this invention, and a joint. (B1) It is a cross-sectional enlarged explanatory view of the T portion of FIG. 8A in which a protrusion is formed on the tapered surface of the second dish type tapered portion. (B2) It is a cross-sectional enlarged explanatory view of the T portion of FIG. 8A in which a recessed portion is formed on the tapered surface of the tapered portion of the second dish type. (C1) It is a cross-sectional enlarged explanatory view of the U portion of FIG. 8A in which a dent is formed on one inclined surface of a chevron convex portion of a thin-walled stainless steel pipe. (C2) FIG. 8 is an enlarged cross-sectional explanatory view of the U portion of FIG. 8A in which a protrusion is formed on one inclined surface of a chevron convex portion of a thin-walled stainless steel pipe.

The best embodiment of the present invention will be described with reference to each figure. In the thin-walled stainless steel pipe expanding device 1 of the first embodiment of the present invention, as shown in FIGS. 1 (a), 1 (b), and FIG. 2, the fitting inner hole 3 into which the thin-walled stainless steel pipe 2 is fitted, and A pipe expansion head 5 having a first dish-shaped tapered portion 4 formed in front of the fitting inner hole 3 and inclined so that the front is expanded, and a thin-walled stainless steel pipe detachably fixed to the front of the pipe expansion head 5. A pipe expansion ring 8 having a fitting hole 6 into which 2 is internally fitted, a second dish-shaped tapered portion 7 continuous with the first dish-shaped tapered portion 4 and inclined so that the front is reduced in diameter, and a fitting inner hole 3 A guide ring 9 arranged on the inner side in the radial direction of the pipe, and a pressure rod 11 inserted into the pipe expansion head 5 and having a rear end connected to a pressure device 10 and a pressure rod 11 to which a thin stainless steel pipe 2 is fitted. It has a pipe expansion rubber 12 fitted in front of the guide ring 9 in the rod 11 and a rubber holding portion 13 formed in front of the pipe expansion rubber 12 in the pressure rod 11. FIG. 2 is a perspective view showing each component of the thin-walled stainless steel pipe expanding device 1 in an exploded manner. Hereinafter, it will be described in more detail.

The tube expansion head 5 is opened in front of the thin-walled stainless steel pipe expanding device 1, that is, on the side where the thin-walled stainless steel pipe 2 is fitted (on the right side in the figure), and the tip portion 16 of the thin-walled stainless steel pipe 2 inserted from the front side is inserted. It has an inset inner hole 3 to be internally fitted.

A first dish-shaped tapered portion 4 is formed in front of the fitting inner hole 3 so as to be inclined so that the front diameter is expanded. That is, the first dish-shaped tapered portion 4 is a conical trapezoid formed by linearly expanding the diameter from the rear end portion having the same diameter as the fitting inner hole 3, that is, the boundary portion with the fitting inner hole 3 toward the front. It is a tapered surface of. On the other hand, a rod insertion hole 17 having a diameter smaller than that of the fitting inner hole 3 is formed behind the fitting inner hole 3, that is, on the side opposite to the side where the thin-walled stainless steel pipe 2 is fitted (on the left side in the drawing). The rod insertion hole 17 is a hole for inserting the pressure rod 11 and is formed in the radial center portion of the tube expansion head 5. Then, the pipe contact surface 18 is formed by the step between the rod insertion hole 17 and the fitting inner hole 3. Further, a male screw portion 19 is formed on the outer peripheral surface of the front portion of the tube expansion head 5, that is, the outer peripheral surface of the cylindrical portion constituting the fitting inner hole 3. On the other hand, the rear end portion 20 of the tube expansion head 5 is coupled to the pressurizing device 10. Here, the rear end portion 20 of the tube expansion head 5 is fitted to the main body frame 21 of the pressurizing device 10 and fixed by the knock pin 38.

The tube expansion ring 8 has a second dish-shaped tapered portion 7 on the inner peripheral surface thereof, which is continuous with the first dish-shaped tapered portion 4 and is inclined so that the front diameter is reduced. That is, the second dish-shaped tapered portion 7 is a conical trapezoidal tapered surface formed by linearly reducing the diameter from the rear end portion having the same diameter as the front end portion of the first tapered portion 4 toward the front. .. Then, the continuous first dish-shaped tapered portion 4 and the second dish-shaped tapered portion 7 form a peripheral groove 22 having a mountain-shaped cross section. Further, a fitting hole 6 into which the thin-walled stainless steel pipe 2 is fitted is formed in front of the second dish-shaped tapered portion 7. Then, the tube expansion ring 8 is detachably fixed in front of the tube expansion head 5. Therefore, here, a female threaded portion 23 is formed on the inner peripheral surface of the rear portion behind the second dish-shaped tapered portion 7, and the female threaded portion 23 is fixed by being screwed into the male threaded portion 19 of the tube expansion head 5. .. Therefore, the tube expansion ring 8 can be freely attached to and detached from the tube expansion head 5. Therefore, it is preferable to form unevenness on the outer peripheral surface of the tube expansion ring 8 for applying a wrench.

The guide ring 9 is a cylindrical body having a constant thickness, which is arranged in close contact with the pipe contact surface 18 on the radial inside of the fitting inner hole 3 and into which the thin-walled stainless steel pipe 2 is fitted, and is a fitting inner hole 3. By being fitted to the pressurizing rod 11 arranged in the radial center portion of the above, the fitting inner hole 3 is arranged coaxially with the fitting inner hole 3 inside the fitting inner hole 3 in the radial direction.

The pressure rod 11 is a rod-shaped member having a circular cross section, which is inserted into a rod insertion hole 17 of a tube expansion head 5 and whose rear end portion 24 is connected to a pressure device 10. Then, in front of the rod insertion hole 17, a guide ring 9 is externally fitted as described above, a tube expansion rubber 12 described later is externally fitted in front of the guide ring 9, and a rubber presser is in front of the tube expansion rubber 12. The portion 13 is formed. Here, the pressure rod 11 is formed with a step portion at a position in front of the guide ring 9 by a predetermined distance, the step portion forms the rubber pressing portion 13, and the front of the rubber pressing portion 13 has a diameter. Is a large diameter portion 25, and behind it is a small diameter portion 26 having a small diameter. Further, by making the diameter of the large diameter portion 25 of the pressure rod 11 slightly smaller than the inner diameter of the thin-walled stainless steel pipe 2, it can function as a guide portion when inserting the thin-walled stainless steel pipe 2. That is, when the thin-walled stainless steel pipe 2 is fitted between the fitting inner hole 3 and the guide ring 9, the thin-walled stainless steel pipe 2 is aligned with the large-diameter portion 25 of the pressure rod 11 having a diameter slightly smaller than the inner diameter of the thin-walled stainless steel pipe 2. By fitting the thin-walled stainless steel pipe 2, the central axis of the thin-walled stainless steel pipe 2 can be fitted straight so as to be coaxial with the fitting inner hole 3 and the central axis of the guide ring 9.

On the other hand, behind the rod insertion hole 17 of the pressurizing rod 11, the rear end portion 24 thereof is connected to the drive rod 28 of the pressurizing device 10. Specifically, male screw portions 29 and 30 are formed on the outer peripheral surface of the rear end portion 24 of the pressure rod 11 and the outer peripheral surface of the front end portion of the drive rod 28, respectively, and these are formed on both sides of the connecting pipe 31. The pressure rod 11 and the drive rod 28 are connected by being screwed into the female threaded portions 32 and 33, respectively. Here, the drive rod 28 is a rod-shaped member that moves rearward on the action of a predetermined pressure due to the operation of the pressurizing device 10. In this embodiment, a hydraulic cylinder is used as the pressurizing device 10. Therefore, as shown in FIGS. 1A and 1B, the pressurizing device 10 is a cylinder portion formed inside the main body frame 21 and through which the hydraulic oil flows through the supply / discharge port 34. The 35, the piston portion 36 that slides in the front-rear direction inside the cylinder portion 35, the drive rod 28 connected to the front of the piston portion 36, and the piston portion 36 that has been hydraulically moved backward are returned to the front. It has a return spring 37 to make it. Further, although not shown, it also has a hydraulic pump for applying pressure to the hydraulic oil supplied to the supply / discharge port 34, and a hydraulic valve for adjusting the flow rate and pressure of the hydraulic oil. In addition, another type of pressurizing device 10 may be used as long as the pressure for operating the pressurizing rod 11 backward can be applied.

As shown in FIGS. 1 (a), 1 (b) and 2, the expanded tube rubber 12 is a cylindrical body having a constant thickness that is fitted in front of the guide ring 9 in the pressure rod 11 and is a guide ring. It is sandwiched and arranged between 9 and the rubber pressing portion 13 of the pressure rod 11. Therefore, the length of the expanding tube rubber 12 in the front-rear direction is formed so as to be substantially the same as the distance between the guide ring 9 and the rubber holding portion 13 of the pressure rod 11 in the state where the pressure rod 11 is located most forward. .. Further, the diameter of the outer peripheral surface of the expanded tube rubber 12 is formed to be smaller than the diameter of the inner peripheral surface of the thin-walled stainless steel pipe 2 so that the thin-walled stainless steel pipe 2 can be fitted externally. Here, the diameter is formed so as to be substantially the same as or slightly smaller than the diameter of the large diameter portion 25 of the pressure rod 11. An elastic material is used as the material of the tube expansion rubber 12, but it is particularly preferable to use a material having high fluidity and a small decrease in volume due to compression. Urethane rubber is used here.

As is often seen in FIGS. 4 and 5 (a1), the expansion ring 8 is formed so that the protrusions 8a are distributed as a whole on the tapered surface of the second dish-shaped tapered portion 7. The protrusion 8a is preferable because a granular one having a rounded tip occupies a small proportion of the tapered surface, and as a result, the recess 2a formed on the surface of the thin-walled stainless steel pipe 2 becomes small. It may be. It is desirable that the protrusions 8a are evenly distributed over the entire tapered surface, and the number thereof is not limited, but it is particularly preferable that the number of the protrusions 8a is four or more. As shown in FIG. 4, what is distributed throughout is arranged on the tapered surface of the second dish-shaped tapered portion 7 at equal intervals from the center of the tube expansion ring 8 and 1 on the same concentric circle from the center. It is desirable, but not limited to, only the number of pieces to be arranged. The chain lines drawn on the tapered surface of the second dish-shaped tapered portion 7 in FIGS. 4 and 5 (a1) indicate concentric circles.

Further, the expansion ring 8 of another embodiment is formed so that the recessed portion 8b is distributed as a whole on the tapered surface of the second dish-shaped tapered portion 7, as is often shown in FIGS. 4 and 5 (b1). It was done. The recess 8b is a small hole with a rounded bottom. The height and width of the bulge 2b formed in the thin-walled stainless steel pipe 2 are determined depending on the depth and diameter of the recess 8b. It is desirable that the recesses 8b are evenly distributed over the entire tapered surface like the protrusions 8a, and the number thereof is not limited, but four or more are particularly preferable. As shown in FIG. 4, what is distributed throughout is arranged on the tapered surface of the second dish-shaped tapered portion 7 at equal intervals from the center of the tube expansion ring 8 and 1 on the same concentric circle from the center. It is desirable, but not limited to, only the number of pieces to be arranged. The chain lines drawn on the tapered surface of the second dish-shaped tapered portion 7 in FIGS. 4 and 5 (b1) indicate concentric circles.

Furthermore, as is clearly shown in FIGS. 6 and 7 (a1), the tube expansion head 5 has a protruding portion 4a formed on the tapered surface of the first dish-shaped tapered portion 4. The protrusions 4a are preferably, but are not particularly limited, having a plurality of rod-shaped protrusions formed at equal intervals radially from the central portion to the outer periphery. Further, as another embodiment, as shown in FIGS. 6 and 7 (b1), the tapered surface of the first dish-type tapered portion 4 of the tube expansion head 5 has the first dish-type tapered portion 4. A recessed portion 4b is formed on the tapered surface. Similarly, it is preferable that the recessed portions 4b have a plurality of rod-shaped recessed portions formed at equal intervals radially from the central portion to the outer peripheral portion, but the recessed portions 4b are not particularly limited.

Next, a method of using the thin-walled stainless steel pipe expanding device 1 will be described. First, as shown in FIG. 1A, the pipe expansion ring 8 and the pipe expansion head 5 are screwed and connected, and then the thin-walled stainless steel pipe 2 is fitted onto the large diameter portion 25 of the pressure rod 11 while being externally fitted. The tip portion 16 of the thin-walled stainless steel pipe 2 is fitted between the fitting inner hole 3 of the pipe expansion head 5 and the guide ring 9. Next, as shown in FIG. 1 (b), the pressurizing device 10 is operated to apply a predetermined pressure to move the pressurizing rod 11 backward. At that time, the rubber pressing portion 13 of the pressure rod 11 moves backward, but the guide ring 9 does not move, so that the tube expansion rubber 12 moves in the front-rear direction between the guide ring 9 and the rubber pressing portion 13 of the pressure rod 11. It is compressed to and bulges outward in the radial direction. As a result, the thin-walled stainless steel pipe 2 is extruded radially outward by the bulging tube expansion rubber 12, but on the outer periphery of the thin-walled stainless steel pipe 2, the first dish-shaped tapered portion 4 of the tube expansion head 5 and the second of the tube expansion ring 8 are formed. Since the peripheral groove 22 (see FIG. 1) having a mountain-shaped cross section is formed by the dish-shaped tapered portion 7, the thin-walled stainless steel pipe 2 bulges along the peripheral groove 22, and the expanded portion 39 of the mountain-shaped convex portion Is formed.

In the process of forming the pipe expansion portion 39, when the protrusion 8a is formed on the tapered surface of the second dish-shaped tapered portion 7, as shown in FIG. 5 (a1), FIG. 5 (a2). As shown in the above, since the thin-walled stainless steel pipe 2 is pressed from the inside by the expanding rubber 12 in the direction of the second dish-shaped tapered portion 7 as shown by an arrow, a recess 2a is formed at a portion abutting on the protrusion 8a. .. Since the dent 2a has the thickness of the thin stainless steel pipe 2, it is not the same shape as the protrusion 8a, but is a shallow dent having a gentle curve whose depth is substantially equal to the height of the protrusion 8a. Further, as shown in FIG. 5 (b1), when the recessed portion 8b is formed on the tapered surface of the second dish type tapered portion 7, as shown in FIG. 5 (b2), the tube expanding rubber 12 A bulge 2b is formed at a portion facing the recess 8b by the pressing action. The height of the bulge 2b is shorter than the depth of the recess 8b due to the thickness of the thin stainless steel pipe 2. When the frontage of the recess 8b is wide, it approximates the depth of the recess 8b. In this way, the recesses 2a and the bulges 2b are formed on one inclined surface of the expansion portion 39, which is a mountain-shaped convex portion of the thin-walled stainless steel pipe 2, by the protrusions 8a and the recesses 8b.

Further, as shown in FIG. 7 (a1), when the protruding portion 4a is provided on the tapered surface of the first dish type tapered portion 4, as shown in FIG. 7 (a2), the thin-walled stainless steel pipe 2 When a recess 2c is formed on the other inclined surface of the pipe expansion portion 39 which is a mountain-shaped convex portion and the recess 4b is provided as shown in FIG. 7 (b1), it is shown in FIG. 7 (b2). As shown above, the protrusion 2d is formed.

Next, after the pipe expansion, the screw between the pipe expansion ring 8 and the pipe expansion head 5 may be removed, and the thin-walled stainless steel pipe 2 may be pulled out forward. The pipe expansion ring 8 may be left fitted to the thin stainless steel pipe 2 and used as a nut when connected to the joint 40 described later, but the tapered surface of the second dish type tapered portion 7 is flat. It may be used in place of a nut or another nut having an uneven shape at a different shape or position from that of the protrusion 8a or the recess 8b. In this case, it is also possible to remove the tube expansion ring 8 from the end on the side opposite to the side on which the tube expansion portion 39 is formed and use it again for tube expansion.

As shown in FIG. 8A, the thin-walled stainless steel pipe 2 expanded by the thin-walled stainless steel pipe expanding device 1 as described above is connected to the joint 40. Here, the joint 40 includes a main body inner hole 42 that penetrates the central portion of the main body 41 in the axial direction, and a packing fitting portion 43 formed by enlarging the diameter of the inner peripheral surface at the end portion of the main body inner hole 42. It has a packing 44 fitted in the packing fitting portion 43, and a male screw portion 45 formed on the outer peripheral surface of the end portion of the main body 41. At the time of connection, the tip portion 16 of the thin-walled stainless steel pipe 2 is fitted into the main body inner hole 42 of the joint 40. When the tip portion 16 of the thin-walled stainless steel pipe 2 has a reduced diameter, it can be easily fitted into the inner hole 42 of the main body of the joint 40. Then, the female threaded portion 23 of the expanded tube ring 8 fitted to the thin-walled stainless steel pipe 2 is screwed into the male threaded portion 45 of the joint 40, and the expanded tube ring 8 is tightened so that the expanded tube portion 39 of the thin-walled stainless steel pipe 2 is expanded. It is sandwiched from both sides by the second dish-shaped tapered portion 7 of the ring 8 and the packing 44 of the joint 40, and is closely fixed.

When the pipe expansion ring 8 is tightened, the protrusion 8a is present on the tapered surface of the second dish-type tapered portion 7 of the pipe expansion ring 8. Therefore, as shown in FIG. 8 (b1), the protrusion 8a Since there is a gap between the thin-walled stainless steel pipe 2 and the one inclined surface of the expansion portion 39, which is a mountain-shaped convex portion, the frictional resistance is reduced by the height of the thin-walled stainless steel pipe 2, and the expansion ring 8 can be easily rotated. Even if the protrusion 8a enters the recess 2a, the inclination angle of the recess 2a is extremely gentle, so that the protrusion 8a can be easily overcome. Further, if one protrusion 8a is formed on the same concentric circle, it is fitted into the recess 2a only once per rotation, so that it is hardly affected. On the contrary, as shown in FIG. 8 (b2), the same applies to the case where the recessed portion 8b is present in the second dish-shaped tapered portion 7 and the bulge 2b is formed on the inclined surface of the thin-walled stainless steel pipe 2.

Further, when a recess 2c is formed on one inclined surface of the expansion portion 39 of the chevron convex portion of the thin-walled stainless steel pipe 2, as shown in FIG. 8 (c1), the packing pressed by the recess 2c. Even if a rotational force is applied to the thin-walled stainless steel pipe 2 due to the entry of the 44, the rotation can be prevented. On the contrary, when the protrusion 2d is formed on one of the inclined surfaces, as shown in FIG. 8 (c2), the protrusion 2d enters the inside of the packing 44 and prevents the thin-walled stainless steel pipe 2 from rotating. Can be.
In the embodiment of the connection mechanism between the thin stainless steel pipe 2 and the joint 40, a colored dish washer 47 provided between the stepped portion 46 of the main body 41 of the joint 40 and the pipe expansion ring 8 is arranged and colored. It is possible to check whether the connection is complete or not by checking whether or not is visible from the outside.

Next, the tube expanding device 1 for thin-walled metal steel pipes according to the second embodiment of the present invention will be described. The difference from the thin-walled stainless steel pipe expansion device 1 of the first embodiment is that the shape of the outer peripheral surface of the front portion of the tube expansion head 5 is also different due to the difference in the shape configuration of the tube expansion ring 8. That is, as shown in FIG. 3A, the tube expansion head 5 is formed with a fitting convex portion 14 instead of the male screw portion 19 (see FIG. 1) on the outer peripheral surface of the front portion thereof, and the tube expansion ring 8 is formed. In place of the female threaded portion 23 (see FIG. 1), a fitting concave portion 15 having a U-shaped cross section is formed on the inner peripheral surface of the rear portion thereof, and the fitting convex portion 14 and the fitting concave portion 15 are formed. The tube expansion ring 8 is detachably fixed to the tube expansion head 5 by fitting the tube expansion ring 8.

As shown in FIG. 3B, the expansion ring 8 is divided into an upper ring 81 and a lower ring 82 by a horizontal line passing through a central axis. A hinge portion 84 is formed at one connection portion 83 between the upper ring 81 and the lower ring 82, and the upper ring 81 and the lower ring 82 rotate and separate from each other around the hinge portion 84. It is configured in. Further, the other connecting portion 85 between the upper ring 81 and the lower ring 82 is formed with a locking portion 86 for locking the upper ring 81 and the lower ring 82 in a coupled state. As the locking portion 86, here, an upper protruding portion 87 and a lower protruding portion 88 projecting outward are formed on the upper ring 81 and the lower ring 82 of the other connecting portion 85, respectively, and the lower protruding portion 88 is vertically upward. A male threaded portion 89 is provided so as to project to the upper portion 87, and a threaded insertion hole 90 for inserting the male threaded portion 89 is formed in the upper protruding portion 87. It is detachably fixed by 91.

The configuration of other parts such as the fitting inner hole 3 and the point where the first tapered portion 4 is formed is the same as that of the first embodiment. The configuration of the tube expansion ring 8 and the tube expansion head 5 is not limited to this, and the tube expansion ring 8 can be detachably fixed to the tube expansion head 5 and the pressure from the tube expansion rubber 12 acts during the tube expansion. However, if the second dish-shaped tapered portion 7 can maintain the state in which the mountain-shaped peripheral groove 22 is formed without being separated from the first dish-shaped tapered portion 4, other configurations can be used. be.

In the thin-walled stainless steel pipe expanding device 1 according to the second embodiment, after expanding the thin-walled stainless steel pipe 2, the wing nut 91 is removed, and the expansion ring 8 is separated and removed to move the thin-walled stainless steel pipe 2 forward. It can be pulled out and removed. Since this tube expansion ring 8 is not used for connection with the joint 40, one tube expansion ring 8 will be used repeatedly. In this case, for the connection with the joint 40, a nut having the same shape as the expansion ring 8 in the first embodiment is used, which is fitted from the other side of the thin-walled stainless steel pipe 2. At this time, the tapered surface of the second dish-shaped tapered portion 7 may be flat or may be provided with a protrusion 8a or a recess 8b.

The present invention can also be applied to a tube expansion device for thin-walled metal pipes other than thin-walled stainless steel pipes.

1 Thin-walled stainless steel pipe expansion device 2 Thin-walled stainless steel pipe 2a Indentation 2b Indentation 2c Indentation 2d Protrusion 3 Fitting inner hole 4 1st dish type taper part 4a Protrusion part 4b Indentation part 5 Tube expansion head 6 Fitting hole 7 2nd dish type taper part 8 Pipe expansion ring 8a Protrusion 8b Recess 9 Guide ring 10 Pressurizing device 11 Pressurizing rod 12 Pipe expansion rubber 13 Rubber holding part 14 Fitting convex part 15 Fitting recess 17 Rod insertion hole 19 Male thread part 23 Female thread part

Claims (7)

A pipe expansion head having a fitting inner hole into which a thin-walled stainless steel pipe is internally fitted, a first dish-shaped tapered portion formed in front of the fitting inner hole and inclined so that the front diameter is expanded, and a front outer periphery of the pipe expansion head. A second that is detachably fixed to the front and has a diameter reduced and inclined so that a chevron shape is formed continuously with the fitting hole into which the thin-walled stainless steel pipe is fitted and the first dish-shaped tapered portion. It is inserted into a pipe expansion ring having a dish-shaped tapered portion, a guide ring arranged inside the fitting inner hole in the radial direction and into which the thin-walled stainless steel pipe is externally fitted, and a rod insertion hole opened in the center of the pipe expansion head. A pressure rod having a rear end connected to a pressurizing device, a pipe expansion rubber fitted in front of the guide ring in the pressure rod, and a pipe expansion rubber formed in front of the pipe expansion rubber in the pressure rod. In a thin-walled stainless steel pipe expanding device having a rubber presser portion,
A thin-walled stainless steel pipe expanding device characterized in that one protrusion or one recess is arranged on a plurality of concentric circles having different diameters on the tapered surface of the second dish-type tapered portion . The pipe expansion head has a male screw portion formed on the outer peripheral surface of the front portion thereof, and the pipe expansion ring has a female screw portion formed on the inner peripheral surface of the rear portion thereof. The thin-walled stainless steel pipe expanding device according to claim 1, wherein the ring is detachably fixed to the expanding tube head. The pipe expansion head has a fitting convex portion formed on the outer peripheral surface of the front portion thereof, and the tube expansion ring has a fitting concave portion formed on the inner peripheral surface of the rear portion thereof, and the fitting convex portion and the fitting concave portion are fitted. The thin-walled stainless steel pipe expanding device according to claim 1, wherein the expanding ring is detachably fixed to the expanding head. The thin wall according to any one of claims 1 to 3, wherein the plurality of protrusions or recesses are distributed on tapered surfaces in which the center angles of the second dish-shaped tapered portions are substantially equal to each other. Expansion device for stainless steel pipes. The thin-walled stainless steel pipe expanding device according to any one of claims 1 to 3, wherein the protrusion is a granular protrusion. The thin-walled stainless steel pipe expanding device according to any one of claims 1 to 5, wherein a protruding portion or a recessed portion is formed on the surface of the first dish-shaped tapered portion. The thin-walled stainless steel pipe expanding device according to claim 6, wherein the protruding portion or the recessed portion has a rod-shaped shape or an elongated groove shape that protrudes radially from the center of the first dish-shaped tapered portion in the outer peripheral direction.

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