JPH10169877A - Joining method of thermoplastic resin pipe and method for judging acceptance/rejection of joining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable bonding free from any difference in the bonding strength irrespective of the dimensional accuracy by fixing a ring having a projected strap part on its side to a resin pipe, and giving the relative motion to a bonded part of a pipe with a pipe joint to melt the resin to perform the bonding in a condition where a pipe end part of a thermoplastic resin pipe is inserted in a thermoplastic resin pipe joint. SOLUTION: Pipe end parts 11, 11' of thermoplastic resin pipes 1, 1' are inserted in a socket 2 which is a thermoplastic resin pipe joint, and rings 3a, 3a' having projected strap parts 31a, 31a' which are projected aside are fitted to the pipe 1, 1' to demarcate space parts 4,4 ' between the pipes 1, 1' and the socket 2. The socket 2 is turned in the circumferential direction around its axis by the rotational force of a drive motor, and an outer wall surface of the pipes 1, 1' and the inner wall surface of the socket 2 are melted, fused and bonded by the friction heat between the outer wall surfaces of the pipes 1, 1' and the inner wall surface of the socket 2 at a contact part of the socket 2 with the pipes 1, 1'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining thermoplastic resin tubes and a method for judging the quality of joining.

[0002]

2. Description of the Related Art As a method of joining thermoplastic resin piping members, a method using rotational friction welding as disclosed in Japanese Patent Application Laid-Open No. S51-118116 is known. In this rotational friction joining method, the pipe material is brought into contact with the pipe material, and at the contact portion, the inner wall surface of one pipe material is brought into contact with the outer wall surface of the other pipe material. The pipe member is rotated in the circumferential direction around the pipe axis, and the resin on the inner and outer wall surfaces of the two pipe members is softened and fused by frictional heat generated between the inner and outer wall surfaces in contact.

[0003] This method is characterized in that it is excellent in productivity as a method for joining a pipe made of a thermoplastic resin and a pipe joint. However, pipes and pipe joints made of thermoplastic resin have variations in pipe diameter and roundness for each product, misalignment at the time of joining, inclination of the axis, etc., and even when joining under constant joining conditions However, there is a disadvantage that the joining state differs in the circumferential direction, and the joining strength varies widely.

Therefore, it has been proposed to provide a taper on the inner surface of the joint so that the molten resin spreads in the circumferential direction (Japanese Patent Publication No. Hei 6-508305).

[0005]

However, according to the above-mentioned method, before the molten resin spreads in the circumferential direction as intended,
Since it flows in the axial direction, that is, in the taper direction, it is effective for variations in the pipe or diameter, but when there is a gap in the circumferential direction as in a pipe with an elliptical cross section, there is a non-joined part in the circumferential direction. And the joining strength varies.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a pipe end or a pipe joint made of thermoplastic resin regardless of the dimensional accuracy.
It is an object of the present invention to provide a method for joining thermoplastic resin pipes having no difference in joining strength and a method for judging the quality of joining.

[0007]

According to a first aspect of the present invention, there is provided a method for joining a thermoplastic resin pipe (hereinafter simply referred to as a "pipe"). When inserted into a pipe joint (hereinafter, simply referred to as a “joint”), the pipe has a ridge that is provided on the side, and a concentric annular ring is formed between the pipe and the joint. As described above, it is fixed to one of the pipe and the joint and mounted so as to be able to abut on the other, giving relative movement to the joint between the pipe and the joint to melt and join the resin.

According to a second aspect of the present invention, there is provided a method of joining pipes according to the first aspect of the present invention, wherein the ring is divided into two, and when the ring is mounted on a pipe or a joint, the pipe is joined to the pipe. After attaching a pair of split semi-annular rings, fix them together,
Before mounting, a pair of half-rings split into two are fixed to each other and then mounted.

According to a third aspect of the present invention, there is provided a method for joining pipes according to the first or second aspect of the present invention, wherein the annular space is opened between the annular ring and the pipe or the joint so that resin can flow out. When the resin is mounted in such a manner, the resin has flowed out of the gap, indicating that the joining is completed.

According to a fourth aspect of the present invention, there is provided a method for judging the quality of a joined product according to the first or second aspect of the present invention, wherein the ring is removed after the joining is completed, and the gap between the ring, the joint and the pipe is removed. The quality of the joining is determined based on whether or not the resin that has flowed into the space has been transferred to the space shape.

In the present inventions 1 to 4, the axial sectional shape of the space portion is not particularly limited, and examples thereof include a square, a triangle, and a sector. The axial cross-sectional area of the space is not particularly limited, and is appropriately selected depending on the nominal diameter. Since it is inefficient, when the nominal diameter is less than 75 mm, 0.5 to 16 mm
² is preferred, and more preferably ² to 9 mm ² .
In the case of a nominal diameter of 75 to 150 mm, 2 to 25 mm
² is preferred, and more preferably 4.5 to 10 mm ² . Furthermore, when the nominal diameter is 150 to 250 mm,
5 to 50 mm ² is preferred, and more preferably 10 to 2
0 mm ² .

The shape of the inner surface of the joint may be parallel to the pipe. However, a tapered shape that widens outward is more effective against dimensional variations and misalignment.

The thermoplastic resin forming the pipe and the joint is not particularly restricted but includes, for example, polyethylene, polypropylene, polybutene, polyvinyl chloride and the like. Different kinds of thermoplastic resins can be used for the pipe and the joint. In this case, it is preferable that the resins have substantially the same melting point.

The material forming the ring is not particularly limited as long as it does not melt by friction.
When polyethylene is used as the thermoplastic resin forming the pipe and the joint, the rotation speed, the surface condition of the pipe and the joint,
Although the degree of circularity differs, the temperature of the ring surface rises to about 300 ° C., so that a so-called engineering plastic having a melting point higher than that may be used, but a metal material such as aluminum, copper, steel, etc. having good wear resistance is used. preferable.

The method of fixing the ring to the joint is not particularly limited as long as the ring can be removed later and does not damage the joint and the pipe. Alternatively, a pair of half-rings may be fixed to each other with a fixing jig such as a clamp, or a pipe or a joint may be inserted and fitted into the ring.

[0016] Some space is created between the ring and the pipe or joint unless the two shapes are perfectly matched.
The present invention 3 indicates that the joining is completed when the resin flows out of the gap. This gap is
Although it depends on the roundness of the pipe and the joint, the gap between the ring and the pipe or the joint is preferably 0.5 to 3 mm. If the gap is too narrow, it is difficult to determine whether resin has flowed out. If the gap is too wide, the resin will flow out of the gap before the space is filled with the resin.

The method of joining by giving the relative motion is not particularly limited. For example, a joint or a pipe may be rotated by a gear provided at the tip of a drive shaft connected to a drive motor. , Joints or tubes may be slid in the circumferential direction.

(Operation) The pipe joining method according to the first aspect of the present invention is characterized in that the pipe end to be joined has a protruding ridge protruding laterally with the pipe end inserted into the joint, and is concentric with the pipe. The ring is fixed to one of the pipe and the joint so as to form a space between the pipe and the joint, and is mounted so as to be able to abut on the other. Melts and joins
The resin melted by the relative motion closes the gap between the pipe and the joint through the space, and the pipe and the joint are firmly adhered.

According to a second aspect of the present invention, there is provided a method for joining pipes according to the first aspect of the present invention, wherein the ring is divided into two parts, and the ring is divided into two parts when the ring is mounted on a pipe or a joint. Since the two rings are fixed after the ring is mounted, or a pair of half-rings divided into two parts are fixed to each other before the ring is mounted, the ring is easily mounted.

According to a third aspect of the present invention, there is provided a method for joining pipes according to the first or second aspect, wherein the ring is mounted so as to open a gap through which resin can flow between the ring and the pipe or the joint. This indicates that the joining has been completed when the resin has flowed out, so that the joining of the pipe and the joint can be easily confirmed.

The method for judging the quality of a joined product according to the fourth aspect of the present invention is the method according to the first or second aspect of the present invention, wherein the resin that detaches the ring after the joining is completed, and flows out into the space between the ring, the joint and the pipe, Since the quality of the joint is determined based on whether or not it is transferred to the space shape, the quality of the joint between the pipe and the joint can be easily confirmed nondestructively.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 (a), (b)
FIG. 2 is a cross-sectional view showing a state in which a ring is mounted in a state where a pipe end of a pipe is inserted into a joint (socket) in the inventions 1 to 4, and FIGS. 2A and 2B are perspective views of the ring. It is.

In FIG. 1A, first, the pipe ends 11, 11 'of the pipes 1, 1' are inserted into the socket 2. Tube 1, 1 '
2 (a) are attached, and the rings 3a, 3a 'are provided with ridges 31 protruding laterally.
a, 31a '. Rings 3a, 3a 'and tube 1,
Spaces 4, 4 ′ are formed between 1 ′ and socket 2. The rings 3a, 3a 'are fixed to the tubes 1, 1' in a state where the tubes 1, 1 'are inserted and fitted, and the convex portions 31a, 31a' are provided.
Are in contact with both end surfaces of the socket 2.

FIG. 1 (b) shows another ring 3b, 3b ′ of FIG. 2 (b) in a state where the tube ends of the tubes 1, 1 ′ are inserted into the socket 2 in the present invention 1, 2 and 4. It is sectional drawing which shows the state which mounted | worn. The rings 3b, 3b 'have first protruding portions 31b, 31b' and second protruding portions 32b, 32b 'protruding sideways in a stepwise manner. Rings 3b, 3b ';
Spaces 4, 4 'are formed between the tubes 1, 1' and the socket 2. The rings 3b, 3b 'are connected to the socket 2 by the ridges 32b, 32b' when the tubes 1, 1 'are inserted and fitted.
And 33b, 33b 'are in contact with the tube.

FIG. 3 is a front view showing a method of joining by giving relative movement to a contact portion between a pipe and a joint in the inventions 1 to 4. Drive shaft 5 connected to a drive motor (not shown)
A gear 51 provided at the end of the socket 2 is engaged with the ridge 21 formed on the socket 2, and the socket 2 is rotated in the circumferential direction around the pipe axis by the rotational driving force of the drive motor, so that the socket 2 At the contact portion with the tubes 1 and 1 ', the outer wall surfaces of the tubes 1 and 1' and the inner wall surface of the socket 2 are melted and fused by frictional heat between the outer wall surfaces of the tubes 1 and 1 'and the inner wall surface of the socket 2. To join.

FIGS. 4A, 4B and 4C are perspective views showing a ring used in the present invention 2. FIG. The halved rings 34, 34 'are fixed to each other with clamp bolts 33 when the rings are mounted on a tube or socket. FIG.
FIG. 5B is a cross-sectional view showing a state where the rings 34 and 34 ′ are connected by a plate 35, and FIG. 5 is a sectional view showing a state where the rings 3 c and 3 c ′ shown in FIG. . If this is used, it serves as a fixture for the pipe when the ring is mounted on the pipe or socket. FIG. 4 (c)
Is the above-mentioned ring 34, 34 ', one side is clamp bolt 3
3, and the other is connected by a hinge 36. Note that a hook may be used instead of the clamp bolt 33.

It is preferable to provide a gap (not shown) of about 0.5 to 1 mm between the divided rings 34 and 34 'as a margin for a pipe or a socket.

FIGS. 6A and 6B are cross-sectional views showing another embodiment of the ring 3a and the space portion 4 used in the present inventions 1 to 4. FIG. The section 4 of the space has a right-angled triangular cross section [FIG.
(A)] and an arc shape (FIG. 6 (b)).

FIGS. 7 (a), (b) and (c) show the present invention.
Ring 3a used for 4 and socket 2 having a taper
It is sectional drawing which shows the relationship with a. The relationship between the inner diameter of the ridge 31a protruding to the side of the ring 3a and the inner diameter of the tapered end of the socket 2a is such that when the inner diameter of the ridge 31a is large (FIG. 7A), the socket 2a Either the case where the inner diameter of the end is large [FIG. 7 (b)] or the case where it is substantially equal [FIG. 7 (c)] may be used, but the case where the inner diameter of the end of the socket 2a is large [FIG. 7 (b)] Is preferred. However, socket 2a
When the inner diameter of the end is substantially equal to the maximum dimension of the tube, it is preferable that the inner diameter of the ridge 31a is large (FIG. 7A).

[0030]

EXAMPLES The present invention will be described in more detail with reference to Examples.

(Embodiment) A medium-density polyethylene socket 2 having the dimensions shown in FIG.
100A medium density polyethylene tube 1 was inserted. At this time, the tube was inserted at an angle of 2 degrees with the axis of the socket. Although only one side of the socket 2 is shown in the drawing, the same applies to the other side. When the outer diameter of the tube 1 was measured with a vernier caliper every 60 degrees, each tube was elliptical as shown in Table 1.

[0032]

[Table 1]

Next, as shown in FIG. 8, an aluminum ring 3 having a height of 3 mm and having a height of 3 mm, which is concentric with the tube 1 and has a protruding ridge portion, is mounted on the socket 2 with the tube 1 or the socket 2. And was fixed so that a space 4 was formed therebetween.

As shown in FIG. 3, a gear 51 provided at the tip of a drive shaft 5 connected to a drive motor (not shown) is engaged with a ridge 21 formed on the socket 2 as shown in FIG. The socket 2 is rotated at 1250 rpm around its tube axis by the rotational driving force of the driving motor.
After 15 seconds, the resin flowed out of the gap between the ring 3 and the socket 2. Then, when the rotation was stopped, the ring 3 was removed, and observation was made with the naked eye, resin leakage from the socket 2 was confirmed all around, and the inner surface shape of the ring 3 was transferred.

(Comparative Example) In the same manner as in the example except that the ring was not attached, when the socket 2 was rotated for 15 seconds, the rotation was stopped, and when the joint was observed with the naked eye, the resin flowed out. There were places where there were, and places where they did not flow at all.

(Peeling Strength) The joints of the joined products obtained in the examples and comparative examples were cut at a position corresponding to the part where the outer diameter was measured to a width of 10 mm to obtain a test piece shown in FIG. As shown in FIG. 10, a piece 6 of the tube was
tt-joined and cut the tube end 6 and the tube 1 at 50 mm / min.
, And peeled to determine the shear strength. Table 2 summarizes the obtained shear strengths.

[0037]

[Table 2]

[0038]

As described above, the method for joining thermoplastic resin pipes according to the first aspect of the present invention can provide a joined product having no difference in joining strength regardless of the dimensional accuracy of the pipe end or the pipe joint.

Since the joining method of the thermoplastic resin pipe of the present invention 2 is as described above, the ring used in the present invention 1 can be easily mounted.

Since the method of joining a thermoplastic resin pipe according to the third aspect of the present invention is as described above, completion of joining of the pipe and the joint can be easily confirmed.

Since the method for judging the quality of the joint of the present invention 4 is as described above, the quality of the joint between the pipe and the joint can be easily confirmed without destruction.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a state in which a ring is mounted in a state where a pipe end of a pipe is inserted into a socket in the inventions 1 to 4, and FIG. It is sectional drawing which shows the state which mounted | worn.

FIG. 2A is a perspective view of a ring, and FIG. 2B is a perspective view of another ring.

FIG. 3 is a front view showing a method of applying a relative motion to a joint between a pipe and a joint to be used in the inventions 1 to 4 for joining.

FIG. 4 is a perspective view showing a ring used in the second embodiment of the present invention, in which the rings are fixed to each other with clamp bolts (a), the rings are connected by a plate (b), and a ring is shown. (C) in which one side is connected with a clamp bolt and the other is connected with a hinge.

FIG. 5 is a sectional view showing a state where the ring shown in FIG. 4 (b) is mounted on a tube and a socket.

FIGS. 6A and 6B are cross-sectional views showing another form of a ring and a space used in the present inventions 1 to 4, respectively.

FIGS. 7A, 7B, and 7C are cross-sectional views showing a relationship between a ring used in the present inventions 1 to 4 and a tapered socket 2a.

FIG. 8 is a cross-sectional view showing a state in which a ring is used in a state where a tube end of the tube is inserted into a socket and used in the example.

FIG. 9 is a cross-sectional view showing a test piece used in an example.

FIG. 10 is a cross-sectional view showing a peel test of an example.

[Explanation of symbols]

 1, 1 'pipe (thermoplastic resin pipe) 11, 11' pipe end 2 socket (thermoplastic resin pipe joint) 3a, 3a ', 3b, 3b', 34, 34 'ring 31a, 31a', 31b, 31b 'ridge 4, 4' space

Claims (4)

[Claims] 1. A circle concentric with a thermoplastic resin pipe having a projecting ridge protruding laterally with a pipe end of a thermoplastic resin pipe to be joined inserted into a thermoplastic resin pipe joint. The ring is fixed to one of the thermoplastic resin pipe and the thermoplastic resin pipe joint so as to form a space between the thermoplastic resin pipe and the thermoplastic resin pipe joint, and is mounted so as to be able to abut on the other, A method for joining thermoplastic resin pipes, wherein relative movement is applied to a joint between a thermoplastic resin pipe and a thermoplastic resin pipe joint to melt and join the resin. 2. The method according to claim 1, wherein the ring is divided into two, and a pair of semi-circles divided into two when the ring is mounted on a thermoplastic resin pipe or a pipe joint. The method for joining thermoplastic resin pipes according to claim 1, wherein the two are fixed to each other, or a pair of half-rings divided into two parts are fixed to each other before being mounted, and then mounted. 3. The above-mentioned ring is mounted so that a gap through which the resin can flow out is opened between the ring and the thermoplastic resin pipe or the joint of the thermoplastic resin. The method for joining thermoplastic resin tubes according to claim 1, wherein the completion is indicated. 4. The joining method according to claim 1, wherein the ring is detached after the joining is completed, and flows out into a space between the ring, the thermoplastic resin pipe joint, and the thermoplastic resin pipe. A method for determining the quality of a bonded product, wherein the quality of the bonded product is determined based on whether or not the transferred resin is transferred to a space shape.