JP7149672B1 - Metal pipe connection method - Google Patents

Abstract

A pipe connection method capable of connecting pipes in a short time is provided. A thin cylindrical brazing material 10 is formed in advance on the inner surface 2A of a through hole of a pipe joint 1, and while rotating the pipe joint 1 at high speed, a pair of pipes P, P are pushed in to rotate. The brazing material 10 is melted by frictional heat and joined. [Selection drawing] Fig. 4

Description

The present invention relates to a method for connecting metal pipes.

The present inventor has proposed many pipe joints and pipe connection structures (methods). For example, a patent application has been filed for a pipe joint having a structure as shown in FIGS. 15 and 16 (see Patent Document 1).
That is, the conventional pipe joint structure shown in FIGS. 15 and 16 has the following configuration.

That is, a flare joint main body 20' having a male threaded portion 20A' and a reduced diameter tapered portion 20B' on each of the two sides in the axial direction, and a bag having a female threaded portion 15A' screwed onto the male threaded portion 20A'. and a nut 15'; two connected pipes P' to be connected to each other are formed with a tip enlarged diameter tube portion ₅ ' extending from the tip surface 3' to a predetermined axial center dimension L5'. At the same time, a tapered stepped portion 10' is formed at the boundary between the tip enlarged diameter tube portion 5' and the basic diameter tube portion 6'; and an inner core 30' having a sloped surface 32' that abuts on the reduced diameter tapered portion 20B'; A closed circular ring 25' is provided inside the cap nut 15', and is fitted to the tip enlarged diameter tube portion 5' through the tapered stepped portion 10' of P'. The urging force for reducing the diameter in the direction maintains the sealed state between the tip enlarged diameter tube portion 5' of the pipe P' and the connecting tube portion 31' of the inner core 30'; furthermore, the flare joint of the cap nut 15' The force in the axial direction due to screwing to the main body 20' is transmitted to the inner core 30' via the ring 25', and the flare joint main body 20' has a reduced diameter taper portion 20B' and the inner core 30'. It is constructed so as to maintain a press-sealed state with the sloped surface 32'.
Moreover, a plurality of independent small protrusions 36' having a triangular or Mt.

Japanese Patent No. 6730759

The conventional pipe joints shown in FIGS. 15 and 16 omit plastic or rubber sealing materials, and can exhibit excellent sealing performance against fluids such as refrigerants over a long period of time. In addition, it is an excellent pipe joint that can exhibit strong pull-out resistance and withstand high pressure.
However, it has been found that the pipe joints shown in FIGS. 15 and 16 have the following problems (demerits).
That is, (i) the number of parts is extremely large, and (ii) the shape and dimensions of the in-core 30' are strictly required, making it difficult to manufacture. (iii) It is not easy to manufacture each part and the pipe joint is expensive, and (iv) Parts may be dropped or lost at the piping connection site. It has recently become clear that

Therefore, in the metal pipe connection method according to the present invention, a thin cylindrical brazing material is formed in advance on the inner surface of the straight through hole, and a large number of small uneven teeth are formed in advance on the outer peripheral surface of the metal pipe joint. A large-diameter drive gear having small uneven teeth meshing with the small uneven teeth is rotated at high speed about the axis of the through hole, and a pair of metal pipes are pushed into the openings at both ends of the through hole in a non-rotating state . The brazing filler metal is melted by the rotational frictional heat between the outer peripheral surface of the tip of the pipe and the brazing material, and the outer peripheral surface of the tip of the pipe and the inner surface of the through hole of the pipe joint are joined ; When the connection is completed, the small concave-convex teeth remain on the pipe joint.

In addition, a pipe tip-stopping ridge portion is formed at the center portion in the axial direction of the inner surface of the linear through hole of the pipe joint; It has a tapered inner peripheral surface that abuts against the portion and gradually expands in the axial outward direction .

In addition, the pipe joint has a pair of gear portions having a large number of small concave-convex teeth projecting from both sides in the axial direction of the outer peripheral surface, and a central recessed peripheral groove is formed between the pair of gear portions; A portion of the outer peripheral edge of the disk-shaped retaining ring that prevents the pipe joint from unexpectedly moving in the axial direction when pushing the pair of pipes into the openings at both ends of the through hole, It is fitted into the above-mentioned central concave circumferential groove of the pipe joint.
Further, the pipe joint has a central gear portion having a large number of small concave-convex teeth projecting from the central portion of the outer peripheral surface in the axial direction, and small-diameter cylindrical portions are formed on both sides of the central gear portion in the axial direction; A portion of the outer peripheral edge of the disk-shaped retaining ring that prevents the pipe joint from unexpectedly moving in the axial direction when pushing the pair of pipes into the openings at both ends of the through hole, Fit into the small-diameter cylindrical portion of the pipe joint.

In addition, the pipe joint has a pair of gear portions having a large number of small concave-convex teeth projecting from both sides in the axial direction. A trapezoidal central concave peripheral groove is formed between the two inner side surfaces and is formed on an inclined surface with an increasing interval dimension, and is gradually expanded in the radial direction; setting the wall thickness dimension of the outer peripheral edge of the disk-shaped retainer ring, which prevents the pipe joint from suddenly moving in the axial direction, to gradually decrease radially outward, Both surfaces of the outer peripheral edge have inclined surfaces, and are fitted into the central recessed peripheral groove of the above-mentioned trapezoidal cross section of the pipe joint. It is configured to prevent sudden movement in a direction.

According to the present invention, the number of parts can be minimized, and pipes can be joined (connected) with one inexpensive pipe joint. The brazing filler metal inside the pipe joint is melted in several seconds to 20 seconds by the rotational frictional heat generated by the rotation of the pipe joint, completing the quick joint (connection) work between the pipes. In addition, the outer diameter of the pipe connection portion (pipe joint) is small and compact, and there is also the advantage that the distance between a plurality of pipes that have been connected can be reduced, and that the plurality of pipes can be arranged compactly.

An example of a pipe joint used for pipe connection is shown, (A) is a longitudinal sectional view, and (B) is an enlarged view of a main part. 1 is a partial cross-sectional side view showing an embodiment of a pipe connection method according to the present invention; FIG. FIG. 3 is a cross-sectional view taken along the line AOA of FIG. 2; FIG. 4 is an enlarged cross-sectional view of a main part sequentially showing a state in which the tip of a pipe is pushed into a rotating pipe joint while a brazing filler metal is melted by rotational frictional heat. 1 is a cross-sectional view showing an embodiment of a pipe joint and showing a pipe connection completion state; FIG. FIG. 4 is a cross-sectional view showing another embodiment of a pipe joint; FIG. 10 is a partial cross-sectional front view showing another embodiment of the pipe connection method according to the present invention; It is a cross-sectional view showing a pipe connection completion state. FIG. 4 is a cross-sectional view showing another embodiment of a pipe joint; FIG. 10 is a partial cross-sectional front view showing another embodiment of the pipe connection method according to the present invention; It is sectional drawing which showed the pipe connection completion state, Comprising: (A) is sectional drawing of whole, (B) is an expanded sectional view of the principal part W of (A). It is a front view which shows one Example of a pipe connection apparatus. It is a top view of a pipe connection device. It is a right side view of a pipe connection device. FIG. 10 is a cross-sectional view of a conventional example in a connection completed state; FIG. 10 is a cross-sectional view of a conventional example in an exploded state;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on the illustrated embodiments.
1 to 4 show one embodiment of the present invention, 1 is a metal pipe joint, a thin cylindrical brazing material (brazing material) 10 is provided on the inner surface 2A of a straight through hole 2. is formed in advance.

An annular projection 3 having a small rectangular cross-section is formed at the central portion of the inner surface 2A of the through hole 2 of the pipe joint 1 in the axial direction.
Further, the thin cylindrical brazing material 10 has an inner end 10A in contact with the ridge 3 and has a tapered inner peripheral surface whose diameter gradually increases in the axial outward direction.
The brazing material 10 is welded to the inner surface 2A of the pipe joint 1 while being melted at a temperature exceeding its melting point. Alternatively, it is also possible to pour preheated and melted brazing material into a molding die or the like, solidify it into a cylindrical shape, remove it, and press-fit it to the inner surface 2A of the through hole 2 of the pipe joint 1 to fix it. is.

The average thickness T10 of the brazing material ₁₀ , which has the tapered inner peripheral surface and the outer peripheral surface has the same outer diameter, is set to 0.1 mm to 2 mm, and the inclination angle θ of the inner peripheral surface (see FIG. 1B) ) shall be between 1° and 3°. Desirably, it is 1.5° to 2.5°.
As the brazing material (brazing material) 10, BAg silver brazing material, BAl aluminum brazing material, BCuP phosphorous copper brazing material, BCuZn brass brazing material, etc. are used. The material of the brazing material of the same kind as the material of the pipe P and the material of the main body of the pipe joint 1 is selected.

The pipe joint 1 has a large number of small uneven teeth 5 formed on its outer peripheral surface (as shown in FIGS. 1 and 3).
In particular, as shown in FIGS. 1A and 3, (a pair of) gear portions 8, 8 having a large number of small concave-convex teeth 5 are projected on both sides of the outer peripheral surface 6 in the axial direction. A central recessed peripheral groove 9 is formed between the pair of gear portions 8 , 8 .

As shown in FIGS. 2 and 3, the pipe connection device 30 includes two disk-shaped retaining rings 12, 12 which retain the pipe joint 1 so as to be rotatable (from below) about _one horizontal axis L1. and a disk-shaped retaining ring 13 that is rotatably retained from above.
A portion of the outer peripheral edges of the upper and lower disk-shaped retaining rings 13; 12, 12 is fitted into the central recessed peripheral groove 9 of the pipe joint 1 (mutually rotating and contactable).

In the pipe connection method of the present invention, as shown in FIGS. 3 and 4, the metal pipe joint ₁ is rotated around the axis L1 of the through hole ₂ at high speed (see arrow M1). , a pair of metal pipes P, P are pushed in from the openings 2C, 2C on both ends of the through hole 2 as indicated by the arrow Y. As shown in FIG. By pushing the pipes P, P in the direction of arrow Y while rotating at high speed as shown by arrow M1, the rotational frictional heat between the outer peripheral surface ₁₄ of the tip end of the pipe P and the brazing material 10 causes the brazing material to 10 is melted, and the outer peripheral surface 14 of the tip of the pipe P and the inner surface 2A of the through hole 2 of the pipe joint 1 are joined.
In FIG. 4, as the pipe P is inserted deeper in order from (A) to (B) to (C), the solid brazing filler metal 10 shown in dots is shown in a mesh form. It can be seen that the state changes to a melted state.

2 and 3, reference numerals ₁₅ and ₁₅ denote large-diameter drive gears, which rotate in the direction of arrow M15 about the axis L15 as a set of two gears.
Since the pipe joint 1 has two gear portions 8, 8, two large-diameter drive gears 15, 15 are also provided, and a disk-shaped retaining ring 13 is interposed therebetween.

The large-diameter drive gear 15 has small uneven teeth 25 for meshing with the small uneven teeth 5 of the pipe joint 1 . The large-diameter drive gear 15 causes the pipe joint ₁ to rotate at high speed in the direction of arrow M1. , the pipe joint 1 can rotate while maintaining a stable posture even when the pipe P is pushed in the direction of the arrow Y, and the pipe joint ₁ does not move in the direction of the axis L1.
In other words, when the pair of pipes P, P are pushed into the openings 2C, 2C on both ends of the through hole 2, the pipe joint ₁ is prevented from unexpectedly moving in the direction of the axis L1.

In FIG. 2, 16 indicates a small drive gear having a hexagonal hole 17 into which the output shaft of a portable power tool can be inserted. By inserting the output shaft of a small portable power tool into the hexagonal hole 17, pipe connection work (shown in FIG. 4) can be performed easily and quickly.
2 to 4, when the brazing material 10 is melted by rotational frictional heat and the joining (connection) between the pipes P is completed, the state shown in FIG. By stopping the rotation and moving the disk-shaped retaining rings 12, 12 downward by the vertical movement mechanism 18, the pipes P, P to which the pipe joint 1 is attached can be easily removed. In particular, as will be described later with reference to FIG. 14, if the upper arm 43A of the clamping arm 43 is swung upward about the axis _L46 to release the upper arm 43A, the pipes P, P and the pipe can be more easily separated. Joint 1 can be removed. (Of course, it is also easy to set the first pipe joint 1 and the pipes P, P.)

Therefore, even in the final pipe connection state--that is, the final state in which the pipes P and P are connected to each other and the fluid forming part of the entire pipe is sent--the above-mentioned small concave-convex teeth 5, 5 is designated as fitting 1 and left as it is.
In other words, the parts that played the leading role (function) of rotating the pipe joint--the small concave-convex teeth 5, 5---to generate rotational frictional heat for melting the brazing filler metal 10, are not removed. , remains until the final pipe connection completion state. That is, the outer diameter of the small concave-convex tooth 5 is so small that it does not interfere with the entire piping (see FIG. 5).

6-8 show another embodiment of the present invention.
The pipe joint 1 has a central gear portion 20 having a large number of small concave-convex teeth 5 protruding from the central portion of the outer peripheral surface 19 in the axial direction. Small diameter cylindrical portions 21, 21 (with an outer diameter smaller than 20) are formed.
The shape of the through hole 2, the point of having a central ridge portion 3, and the shape and arrangement of the brazing filler metals 10, 10 are the same as in the embodiment of FIG.

As shown in FIG. 7, two disk-shaped retaining rings 12, 12 are provided below. Moreover, the two retainer rings 12, 12 are integrally connected by the small-diameter cylindrical portion 12C. Part of the outer peripheral edges of the two disk-shaped retaining rings 12, 12 thus integrated is fitted into the small-diameter cylindrical portions 21, 21 on both sides of the pipe joint 1. As shown in FIG.
In this way, the lower support rotor 24 integrally having the retaining rings ₁₂ , 12 looks like the embodiment described with reference to FIG. Two are arranged separately on the left and right.

Also, the large-diameter drive gear 15 is a single piece, and has a structure in which two upper disc-shaped retaining rings 13, 13 are held in contact with both side surfaces thereof.
A large-diameter drive gear 15 and two disk-shaped retaining rings 13, 13 are attached to a drive shaft 22 rotated by an electric motor _M0 via a key 23 (or a spline not shown). . Parts (outer peripheral edges) of the upper disk-shaped retaining rings 13, 13 are fitted into the small-diameter cylindrical portions 21, 21 of the pipe joint 1. As shown in FIG.

Then, as shown in FIGS. 4 and 7, when the pair of pipes P, P are pushed into the openings 2C, 2C at both ends of the through hole 2, the pipe joint ₁ unexpectedly moves in the direction of the axis L1. This is prevented by four disk-shaped holding rings 12, 12, 13, 13.
FIG. 8 shows a pipe connection structure in a state where connection is completed by the pipe connection device and connection method shown in FIG.

9-11 show another embodiment of the present invention.
That is, as shown in FIGS. 9 and 10, the pipe joint 1 has a pair of gear portions 8, 8 having a large number of small concave-convex teeth 5 projecting from both sides in the axial direction. The facing inner side surfaces 8Y, _8Y of the portions 8, 8 are formed as inclined surfaces whose interval dimension expands in the radially outward direction in a longitudinal section--that is, a section including the axis L1.
As a result, a trapezoidal center recessed peripheral groove 29 that gradually expands in the radial direction is formed between the two inner side surfaces 8Y, 8Y.

To prevent unexpected movement of the pipe joint ₁ in the direction of the axis L1 when pushing the pair of pipes P, P into the openings 2C, 2C at both ends of the pipe joint 1, as shown in FIG. The disk-shaped retainer rings 12 and 13 have trapezoidal cross-sections at their outer peripheral edges.
In other words, the thickness of the disk-shaped retainer rings 12 and 13 is set so as to gradually decrease radially outward at the outer peripheral edge, and the cross section is trapezoidal, and both sides of the outer peripheral edge are inclined surfaces. 12T, 12T; 13T, 13T.
Then, the outer peripheral edge of the trapezoidal cross section of the retaining ring 12 having the inclined surfaces 12T, 12T is fitted into the central recessed circumferential groove 29 of the pipe joint 1, and at the same time, the retaining ring 13 having the inclined surfaces 13T, 13T is fitted. The outer peripheral edge of the trapezoidal cross section of is fitted to hold the pipe joint ₁ rotatably from below and above, and to prevent accidental movement in the direction of the axis L1.

By the way, in the embodiment shown in FIG. 10, the large-diameter drive gears 15, 15 having teeth (gear portions) meshing with the gear portions 8, 8 of the pipe joint 1 and the retaining ring (arranged therebetween) 13 indicates the case of an integral shape (integrated one).
By forming such an integral shape (integrated one), the rigidity and strength are improved (compared to the case of FIG. 3, etc.), and the rotational driving of the pipe joint 1 and the axial center L are more reliably and stably performed. Prevention of minute positional deviation (movement) in _one direction can be achieved.

Next, FIGS. 12 to 14 show an embodiment of a pipe connecting device used for the pipe connecting work described above. 12 to 14 have already been partially illustrated and briefly explained in FIGS. be.
It has two parallel plate members 36, 36 in parallel, and this plate member 36 has a lower side plate 37, a rear upper and lower connection plate 38, and an upper side plate 39 when viewed from the side (as in FIG. 14). It has a U-shape, and has a cutout portion 41 with a front opening at the middle position between the upper and lower sides. The pipe joint 1 and the pipe P correspond to the space of the notch 41 as shown in FIG.
2, the (lower) disc-shaped retaining rings 12, 12, the pipe joint 1 supported by them, the tip portions of the pair of connected pipes P, and the (upper) ) The lower half portion of the disk-shaped retaining ring 13 is arranged to correspond to the notch portion 41 in a side view.

2 and 14, a small gear 16, to which a protruding output shaft of a (portable) power tool can be connected, meshes with a large-diameter drive gear 15 to rotate this gear ₁₅ in the direction of arrow M15. _At the same time, the interlocking mechanism 40 reciprocates the clamping arms 43, 43 clamping the pipes P, P from above and below in the directions of arrows J, K. be able to.
That is, the interlocking mechanism 40 is composed of the two gears 44 and 45 shown in FIG. 14, the screw shaft 46, the screw hole 47 (of the clamping arm 43), and the like.

The clamping arm 43 has an upper arm 43A that can swing upward about the axis L ₄₆ of the screw shaft 46 from the horizontal position shown in FIG. and a lower arm 43B (in a horizontal position). Moreover, as shown in FIG. 14, a locking member 48 is provided to keep the upper arm 43A and the lower arm 43B closed.
The lock member 48 is composed of a rotary shaft 48A with a screw hole and a bolt rod 48C pivotally attached to the lower arm 43B by a pin 48B. When the rotating ring 48A is loosened, the lock member ₄₈ is pushed down in the direction of arrow _N48 , and the upper arm 43A is swung around the axis L46 to be opened.
Under such an open state, the fitting 1 can be set and removed (with the pipe connected).

By the way, the upper arm 43A and the lower arm 43B of the clamping arm 43 for clamping the pipe P from above and below are provided with a large number of anti-slip triangular ridges 50 on their inner surfaces.

As described in detail above, the method for connecting metal pipes according to the present invention is such that the thin cylindrical brazing material 10 is formed in advance on the inner surface 2A of the straight through hole 2, and a large number of small uneven teeth 5 are formed on the outer peripheral surface. A preformed metal pipe joint ₁ is rotated at high speed around the axis L1 of the through hole 2 by a large-diameter drive gear 15 having small uneven teeth 25 meshing with the small uneven teeth 5, and the through hole is rotated. A pair of metal pipes P, P are pushed in from the openings 2C, 2C at both ends of the pipe P in a non-rotating state ; By melting, the tip outer peripheral surface 14 of the pipe P and the inner surface 2A of the through hole 2 of the pipe joint 1 are joined ; Since this is a method of leaving the pipe in place, the long pipe P is simply moved (pushed in) directly during the piping (pipe) connection work, and only the pipe joint 1, which is a small component, needs to be rotated at high speed. The brazing material can be melted reliably and easily with high safety. Furthermore, the number of parts is only one for the pipe joint 1, and the shape and dimensions of the pipe joint 1 do not require ultra-precision machining unlike the conventional example (see Figs. 15 and 16). can be made. Also , pipe connection can be performed by brazing in a short time. Moreover, the work (trouble) to remove the small concave-convex teeth 5, which exerted an important function for high-speed rotation, can be omitted, and the time required for the entire pipe connection work can be remarkably shortened, and waste material is not generated. done.

In addition, the inner surface 2A of the linear through-hole 2 is formed with a pipe tip-stopping ridge portion 3 at the central portion in the axial direction. Since it has a tapered inner peripheral surface that abuts against the ridge portion 3 and gradually expands in the axial outward direction, the thin cylindrical brazing material 10 remains axially even while the metal pipe P is being pushed in. It is fixed without escaping in the central direction (inward), and the pipe P can be strongly pushed in in a short period of time (see FIG. 4). In addition, the inner peripheral surface of the brazing filler metal 10 is axially reduced in diameter, and as the pipe P is pushed Y (see FIG. 4), as shown in FIG. Frictional heating of the brazing filler metal 10 accelerates the rate of temperature rise, and the entire brazing filler metal 10 can be melted most efficiently (it is possible to shorten the time required for inserting the pipe).

Further, the pipe joint 1 has a pair of gear portions 8, 8 having a large number of small concave-convex teeth 5 protruding from the left and right sides of the outer peripheral surface 6 in the axial direction. A central recessed circumferential groove 9 is formed in the through hole 2, and when the pair of pipes P, P are pushed into the openings 2C, 2C at both ends of the through hole 2, the pipe joint ₁ unexpectedly moves in the direction of the axis L1. A portion of the outer peripheral edge of the disk-shaped retainer rings 12, 13 that prevent movement is fitted into the central recessed peripheral groove 9 of the pipe joint 1, so that the pipes P, P can be moved in a short time. It becomes possible to push the brazing material and maintain stable brazing quality (see FIGS. 1 to 5).

Further, the pipe joint 1 has a central gear portion 20 having a large number of small concave-convex teeth 5 protruding from the central portion of the outer peripheral surface 19 in the axial direction. Portions 21, 21 are formed, and when the pair of pipes P, P are pushed into both end openings 2C, 2C of the through hole 2, the pipe joint ₁ unexpectedly moves in the direction of the axis L1. A portion of the outer peripheral edge of the disk-shaped retainer rings 12, 12, 13, 13, which prevents this, is fitted into the small-diameter cylindrical portions 21, 21 of the pipe joint 1, so that the pipes P, P It can be pushed in in a short time, and stable brazing quality can be maintained (see FIGS. 6 to 8).

Further, the pipe joint 1 is provided with a pair of gear portions 8, 8 having a large number of small concave-convex teeth 5 on both left and right sides in the axial direction. , 8Y are formed on inclined surfaces whose interval dimension expands in the radial outward direction in the longitudinal section, and a trapezoidal central concave peripheral groove 29 gradually expanding in the radial direction is provided between the inner side surfaces 8Y and 8Y. a disk-like retainer that prevents the pipe joint ₁ from unexpectedly moving in the direction of the axis L1 when the pair of pipes P, P is pushed into the openings 2C, 2C on both ends of the through hole 2; The thickness of the outer peripheral edges of the rings 12 and 13 is set so as to gradually decrease radially outward, and both surfaces of the outer peripheral edges have inclined surfaces 12T, 12T, 13T, and 13T to form a pipe joint. 1, and the inclined surfaces 12T, 12T, 13T, 13T are brought into contact with the inner side surfaces 8Y, 8Y so that the pipe joint 1 is aligned with the axial center L ₁ . Since it is configured to prevent sudden movement in any direction, the pipe joint 1 can be held in a more stable posture, and the brazing material 10 can be joined in a stable and improved quality. Further, as shown in FIG. 10, minute gaps G, G are generated between the groove bottom 29B of the trapezoidal central concave peripheral groove 29 of the pipe joint 1 and the outer peripheral end faces 12P, 13P of the retaining rings 12, 13. Furthermore, the rotational frictional heat with the brazing material 10 during the pushing of the metal pipe P is difficult to escape (to the outside), the prescribed high temperature for brazing is easily maintained, and the brazing quality and strength are high. There are also advantages that can be maintained.

REFERENCE SIGNS LIST 1 pipe joint 2 through hole 2A inner surface 2C openings at both ends 3 ridge portion 5 small uneven teeth 6 outer peripheral surface 8 gear portion 8Y inner surface 9 central concave peripheral groove
10 brazing material
10A inner end
12 Disc-shaped retainer ring
12T Inclined surface
13 Disc-shaped retainer ring
13T Inclined surface
14 Tip Outer Peripheral Surface
15 large drive gear
20 Central gear
21 Small diameter cylindrical part
25 small unevenness
29 Trapezoidal central concave circumferential groove L ₁ axis P Pipe

Claims (5)

A metal pipe joint (1) in which a thin cylindrical brazing material (10) is formed in advance on the inner surface (2A) of a straight through hole (2), and a large number of small uneven teeth (5) are formed in advance on the outer peripheral surface. ) is rotated at high speed around the axis (L ₁ ) of the through hole (2) by a large-diameter drive gear (15) having small uneven teeth (25) meshing with the small uneven teeth (5) , A pair of metal pipes (P) (P) are pushed in in a non-rotating state from both end openings (2C) (2C) of the through hole (2),
Rotational frictional heat between the outer peripheral surface (14) of the pipe (P) and the brazing material (10) melts the brazing material (10) to form the outer peripheral surface (14) of the tip of the pipe (P) and the pipe. Joining the inner surface (2A) of the through hole (2) of the joint (1) ,
Moreover, in the final pipe connection completion state, leaving the small concave-convex teeth (5) on the pipe joint (1)
A metal pipe connection method characterized by: The inner surface (2A) of the linear through-hole (2) is formed with a pipe end-stopping projection (3) at the central portion in the axial direction,
The thin cylindrical brazing material (10) has an inner end (10A) abutting against the ridge (3) and has a tapered inner peripheral surface whose diameter gradually expands in the axial outward direction. The metal pipe connection method according to claim 1. The pipe joint (1) has a pair of gear portions (8) (8) having a large number of small concave-convex teeth (5) projecting from the left and right sides of the outer peripheral surface (6) in the axial direction. A central recessed peripheral groove (9) is formed between the gear portions (8) (8),
When pushing the pair of pipes (P) (P) into both end openings (2C) (2C) of the through-hole (2), the pipe joint (1) moves in the axial center (L ₁ ) direction. A portion of the outer peripheral edge of the disk-shaped retaining rings (12) and (13), which prevents sudden movement, is fitted into the central recessed peripheral groove (9) of the pipe joint (1). do
The metal pipe connection method according to claim 1. The pipe joint (1) has a central gear portion (20) having a large number of small concave-convex teeth (5) protruding from the central portion of the outer peripheral surface (19) in the axial direction . Small-diameter cylindrical portions (21) (21) are formed on both sides in the axial direction from
When pushing the pair of pipes (P) (P) into both end openings (2C) (2C) of the through-hole (2), the pipe joint (1) moves in the axial center (L ₁ ) direction. A portion of the outer peripheral edge of the disk-shaped retaining ring (12) (12) (13) (13) that prevents sudden movement is attached to the small diameter cylindrical portion (21) (21) of the pipe joint (1). 2. The metal pipe connection method according to claim 1, wherein the metal pipe is fitted into the . The pipe joint (1) has a pair of gear portions (8) (8) having a large number of small concave-convex teeth (5) projecting from both sides in the axial direction. 8) facing inner surfaces (8Y) (8Y) are formed as inclined surfaces with an interval dimension expanding radially outward in the longitudinal section, and between the inner surfaces (8Y) (8Y) in the radial direction It has a gradually expanding trapezoidal central concave peripheral groove (29),
When the pair of pipes (P) (P) are pushed into the openings (2C) (2C) at both ends of the through hole (2), the pipe joint (1) moves in the direction of the axis (L ₁ ). The thickness of the outer peripheral edges of the disk-shaped retaining rings (12) and (13), which prevent abrupt movement, is set so as to gradually decrease radially outward, and both surfaces of the outer peripheral edges are It has inclined surfaces (12T) (12T) (13T) (13T) and is fitted into the central recessed circumferential groove (29) of the pipe joint (1) having a trapezoidal cross section, and the inclined surfaces (12T) (12T) (13T) (13T) are brought into contact with both inner side surfaces (8Y) (8Y) to prevent unexpected movement of the pipe joint (1) in the axial center (L ₁ ) direction. The metal pipe connection method according to claim 1 .

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