JPH07241913A - Apparatus and method for welding tubular member - Google Patents

Abstract

PURPOSE:To provide a welding method and its apparatus wherein a size of a bead formed at a weld between tubular members and partial weld strength are always made constant. CONSTITUTION:The welding apparatus is equipped with a pair of holding devices 16, 18 to hold tubular members 12, 14 of thermo-plastic resin made, and a heating body 20 to melt by heating end faces 13, 15 of the tubular members. A controller controls the holding devices and driving devices 50, 62 of the heating body so that the heating body is transferred to a retreating position after completion of melting of the end faces of the tubular members, and the holding device 16 is transferred in a specific direction to make the end faces contact each other thereafter. Further, after mutual contact of the end faces, the controller controls the driving devices 50 so that the holding device 16 is further transferred by a specific distance. In that case, time from completion of melting of the end faces to contact of the end faces is short, and a transfer speed of the holding device after mutual contact of the end faces almost constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for abutting and welding the end faces of a pair of tubular members made of a thermoplastic resin.

[0002]

2. Description of the Related Art Conventionally, tubular members made of various synthetic resins have been used for various purposes. For example, tubular members molded from general-purpose thermoplastic resins such as polyvinyl chloride and polypropylene are widely used as water pipes for houses, factories, etc., and pipes for chemicals. Also,
A tubular member made of a thermoplastic resin having excellent heat resistance and solvent resistance such as polyphenylene sulfide resin (hereinafter referred to as “PPS”), polyether ether ketone, and polyvinylidene fluoride is an ultra pure material for manufacturing electronic devices such as LSI. Used as water piping.

When piping is actually performed using such a tubular member made of a thermoplastic synthetic resin, it is necessary to join the tubular members to each other or the tubular member and the tubular ends of the devices. Although there are various methods for joining tubular members, a welding method has been widely employed in which end faces of tubular members facing each other are heated and melted by a heating body, and then the melted end faces are brought into pressure contact with each other to be joined.

This welding method is disclosed in Japanese Patent Publication No. 63-2901.
As disclosed in Japanese Unexamined Patent Publication No. 1 and the like, there is a contact type in which an end surface to be welded is brought into direct contact with a heating body to melt, but when the material of the tubular member is PPS, polyetheretherketone or the like, It becomes difficult to peel off the tubular member. Therefore, in recent years, in particular, in the case of a tubular member made of PPS or the like, a gap is provided between the end surface to be welded and the heating element as disclosed in JP-A-1-110128. A non-contact welding method for melting the end faces tends to be adopted.

As an apparatus used in the contact-type welding method, one disclosed in Japanese Patent Laid-Open No. 63-4938 is known, and an apparatus used in the non-contact-type welding method is disclosed in Japanese Patent Application Laid-Open No. Hei. What is disclosed in Japanese Laid-Open Patent Publication No. 193004 is known. Each of these conventional devices includes a clamp for horizontally and coaxially gripping a pair of tubular members to be joined, and a heating element disposed between the clamps, one of the clamps being provided. A pneumatic cylinder or a hydraulic cylinder allows the other clamp to approach and separate from the other clamp, and the heating element can be retracted from the movement path of the tubular member. In such a device, the tubular members can be joined together by melting the end surface of the tubular member to be welded by the heating body and then bringing the movable clamp closer to the other clamp.

[0006]

SUMMARY OF THE INVENTION In the above welding apparatus,
The end faces of the heated and melted tubular member are pressed against each other with a constant pressure by an air pressure cylinder or the like to be welded. Therefore, the melted end surfaces are pushed against each other until the pressure by the pneumatic cylinder or the like and the reaction force of the melted end surface of the tubular member are balanced.

By the way, even if resins made by the same manufacturer and having the same chemical structure have variations in molecular weight distribution, kneading, etc., even if they are heated at the same temperature, the degree of melting may differ. Further, the degree of melting of the end surface of the tubular member largely depends on the temperature of the atmosphere, the presence or absence of convection, and the like. Therefore, even if the contact pressure is constant, the welding result is not always constant. For example, when the melting depth of the end surface of the tubular member is shallow, the protrusions, so-called beads, formed on the inner or outer circumference of the welded portion are small, and conversely, when the melting depth is deep, the bead is large.

Further, Japanese Patent Laid-Open No. 63-4938 discloses that
The end faces of the tubular member are brought into contact with each other, then one of the tubular members is moved by a hydraulic cylinder to a position where appropriate penetration occurs between the end faces, and then an electromagnetic relief valve between the hydraulic cylinder and the hydraulic oil supply pump. There is disclosed a means for adjusting the set pressure of to keep the contact pressure constant. However, since the viscosity of the hydraulic oil and the operating speed of the electromagnetic relief valve vary depending on the temperature, the size of the formed bead may vary.

Further, since the tubular member made of a thermoplastic resin is hardened in a short time after heating, the time from melting the end faces of the tubular member to bringing the end faces of the tubular members into contact with each other should be as short as possible. Is desirable. However, in the above-mentioned conventional device, since hydraulic pressure or air pressure is used for moving the tubular member, there is a problem that it takes a considerable time from melting to contacting the end faces. Particularly, in the contact type welding apparatus, a step of separating the end surface of the tubular member from the heating plate is required, which further takes time.

The present invention solves the above conventional problems,
It is an object of the present invention to provide a welding apparatus and method in which the size of a bead formed in a welded portion between tubular members and the welding strength of the portion are always constant.

[0011]

In order to achieve the above object, the invention according to claim 1 is such that a pair of end faces to be welded of a thermoplastic resin tubular member are arranged to face each other with a space therebetween. The tubular member is held coaxially, and the heating element is arranged between the end surfaces in a state of being separated from each of the end surfaces, and the heating element is operated to heat and melt the end surface by the heat of the heating element. After the heating is completed, the heating body is removed from between the end faces, one of the tubular members is moved in a predetermined direction relative to the other tubular member to bring the end faces into contact with each other, and the end faces are joined to each other. After the contact, the one tubular member is further moved relative to the other tubular member in the predetermined direction, and after the contact between the end faces, the one tubular member becomes the other tubular member. If it is moved by a predetermined amount, In the method for welding a tubular member that holds both of the tubular members stationary, the time from the completion of heating of the end faces until the end faces are brought into contact with each other is such that the end faces become unsuitable for welding. The relative movement speed of the one tubular member with respect to the other tubular member is substantially constant in most of the time from the contact of the end faces to the stationary of the tubular member. I am trying.

[0012] According to a fifth aspect of the present invention, a pair of gripping devices for gripping each of the pair of thermoplastic resin tubular members and holding them horizontally and coaxially, and one of the gripping devices is the other. Welding of a tubular member provided so as to be movable between a first drive device for moving toward and away from the gripping device, a heating position between the gripping devices, and a retracted position separated from the heating position. A heating body for heating and melting the end face to be heated, a second drive device for driving the heating body, and the first
In a welding device for a tubular member, comprising: a drive device for controlling the second drive device and a controller for controlling the second drive device, the control device, after the heating of the end surface of the tubular member gripped by the gripping device is completed, A means for controlling the second drive device to move the heating element from the heating position to the retracted position; and one of the gripping devices relatively moving in a predetermined direction with respect to the other gripping device. A means for controlling the first driving device so as to bring them into contact with each other, and further, after the contact between the end surfaces, moving the one gripping device further relative to the other gripping device in the predetermined direction. After the contact between the means for controlling the first drive device and the end faces, if the one gripping device is moved by a predetermined amount with respect to the other gripping device, both of the gripping devices are stopped. Tebo And a means for controlling the first drive device so that the time from the completion of heating of the end faces until the end faces are brought into contact with each other is set so that the end faces are in an inappropriate state for welding. It is a time that can be prevented, and the relative movement speed of the one gripping device with respect to the other gripping device is set to be substantially constant in most of the time from the contact between the end faces to the resting of the gripping device. It has a feature.

[0013]

In this way, the time from the completion of heating and melting of the end faces of the tubular member to the contact between the end faces is preferably 2
When the time is limited to within 2 seconds, more preferably within 1 second, the end face is prevented from solidifying.

After the end face contact, the tubular member is moved toward the other tubular member at a constant speed by a predetermined amount suitable for welding. Since the size of the bead generated at the welded portion corresponds to the relative movement amount of the tubular members, the size of the bead formed is substantially constant. Furthermore, in this case, since the pressure contact pressure gradually increases with the movement of the tubular member, the welding strength is enhanced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals.

1 to 3 show an embodiment of a welding device for tubular members according to the present invention. As shown in the figure, this welding device 10 basically comprises a pair of clamps (grip devices) for gripping tubular members 12 and 14 made of thermoplastic resin, for example, polyarylene sulfide resin or PPS. ) 16, 18 and these clamps 1
And a heating element 20 disposed between the six and eighteen.

Each of the clamps 16 and 18 is provided with a pair of clamp members 22a and 22b, each of which is formed by arranging a plurality of clamp plates in parallel. V-shaped notches 24a and 24b are formed at the side edges of these clamp members 22a and 22b facing each other. The clamp members 22a, 22b are fixed on sliders 28a, 28b slidably attached to the guide rail 26, respectively, and are brought close to each other by an appropriate driving device 30.
It is supposed to be separated.

Drive device 3 in each clamp 16, 18
0 is substantially the same, and if only one driving device 30 is described, this driving device 30 is
8a, 28b and a rotatable feed screw 32 arranged parallel to the guide rail 26, an electric motor 34 for rotating the feed screw 32, preferably a DC motor, and an end of the feed screw 32. And a rotation mechanism of the motor 34, preferably a winding transmission mechanism including a timing belt 36. In the feed screw 32, the spiral direction of the screw part screwed into one slider 28a is opposite to the spiral direction of the screw part screwed into the other slider 28b, and the pitches of the screw threads are the same. Has become. Therefore, when the DC motor 34 is controlled to rotate its rotating shaft in a predetermined direction, the distance between the sliders 28a and 28b becomes narrower, and when the rotating shaft is rotated in the opposite direction, the distance between the sliders 28a and 28b becomes wider.

In the clamps 16 and 18 as described above, the sliders 28a and 28b are brought close to each other, and the clamp members 22a and
The tubular member 1 corresponding between the notches 24a and 24b of 22b.
The gripping tubular members 12, 14 are positioned on the base 38 of the welding device 10 so that the gripped tubular members 12, 14 extend horizontally and are coaxially aligned with each other when gripping the ends of 2, 2. The reference numeral 40 is a support for mounting the central portions of the corresponding tubular members 12 and 14 and supporting them horizontally. The support 40 includes a support column 42 fixed to the base 38 and extendable in the vertical direction so that the support position can be changed when welding tubular members having different diameters.
It is preferable that it is composed of a fork member 44 provided at the upper end of 2.

Further, the guide rail 26 and the driving device 30 in the one clamp 18 are provided with a base 38 of the welding device 10.
It is fixed to. Therefore, the tubular member 14 gripped by the clamp 18 is immovable with respect to the base 38. On the other hand, the guide rail 26 and the driving device 30 of the other clamp 16 are slidably attached to the guide rail 46 provided on the base 38.
It is fixed at 8. The guide rail 46 extends in the same direction as the central axis of the tubular member 12 to be gripped. Therefore,
By moving the slider 48 along the guide rail 46, the clamp 16 approaches the immovable clamp 18.
The tubular member 12 can be separated from each other, and the end surface of the tubular member 12 gripped by the clamp 16 can be pressed close to the opposing end surface of the other tubular member 14.

The slider 48 is movable along the guide rail 46 by a suitable driving device 50. The drive device 50 is an electric motor 5 fixed on a base 38.
2. Preferably, an AC motor, a DC motor or a stepping motor is provided, and a rotary shaft 54 of the motor 52 is provided.
Extend parallel to the guide rail 46. The rotary shaft 54 is threaded, and the threaded portion is screwed into the slider 48. Therefore, the motor 52 is controlled to rotate the rotary shaft 54.
When is rotated, the slider 48 is moved along the guide rail 46 according to the rotating direction.

A heating element 20 is arranged between the clamps 16 and 18. The heating element 20 is installed via a support plate 60 on a slider 58 slidably attached to a guide rail 56. The guide rail 56 is
A tubular member 1 that is fixed in place on the base 38 between the clamps 16 and 18 and is gripped by the clamps 16 and 18.
It extends in a direction at right angles to the central axes of 2,14.
A drive device 62 is connected to the slider 58. By controlling the drive device 62, the slider 58, and thus the heating element 20 is heated to a heating position between the tubular members 12 and 14 and a retracted position outside thereof (see FIG. 1). And the position shown in FIG. 3). Reference numeral 64 indicates a protective cover for protecting the heating element 20 arranged at the retracted position.

The heating element 20 is composed of a flat plate-shaped case made of, for example, a porous ceramic plate, and a heat source such as a nichrome wire housed in the case. Of course, the heating source of the heating element 20 is not limited to nichrome wire, and the material of the case is not limited to ceramic. Further, the case and the heat source may be integrally cast. Both surfaces of the heating element are heating surfaces that generate heat for melting the end surfaces 13 and 15 of the tubular members 12 and 14, and when the heating element 20 is in the heating position, each heating surface is clamped by the clamps 16 and 18. The end faces 13, 15 to be welded of the gripped corresponding tubular members 12, 14 are directly faced.

Further, the drive device 62 is an electric motor 66 disposed at a rear portion (a portion on the retracted position side of the heating body 20) in the base 38, preferably an AC motor with a reduction gear, a DC motor or a stepping motor. Is equipped with. Motor 6
The rotating shaft of 6 projects from the upper surface of the base 38, and a pulley 68 is attached to the tip thereof. A pulley 70 is rotatably attached to the front portion of the upper surface of the base 38, and a belt 72, preferably a timing belt, is wound between the pulley 70 and the pulley 68 of the motor 66. The timing belt 72 extends in parallel along the guide rail 56, and the slider 58 is connected to a part of the timing belt 72. Therefore, by controlling the motor 66 to drive the timing belt 72, the slider 5
8 can be moved along the guide rail 56.

The slider 58 is further provided with a flat spacer 74 for keeping the distance between the end surfaces 13 and 15 of the tubular members 12 and 14 to be welded constant during heating.
The spacer 74 is composed of a flat plate-shaped spacer body 76 and a cover plate 78 that is detachably attached to each of both surfaces thereof. In addition, the spacer 7
The plate thickness of 4, that is, the distance between the surfaces of the cover plate 78 is
It is made larger than the plate thickness of the heating element 20.

Further, the welding device 10 includes a driving device 3
A control device (see FIG. 4) 80 for controlling the motors 34, 52, 66 of 0, 50, 62 is provided. The controller 80 is located within the base 38 and is programmed to control the motors 34, 52, 66 in the manner described below. Further, the control device 80 constitutes a servo system for each of the motors 52 and 66.

In the welding device 10 having such a structure,
Welding of the tubular members 12 and 14 is performed as follows.
First, when the start switch 82 (FIG. 4) is pressed, the motor 66 is operated, whereby the slider 58 is moved by a certain amount and the spacer 74 is arranged between the clamps 16 and 18.

Next, the end surface 13 to be welded is the spacer 74.
When the tubular member 12 is arranged on the clamp 16 so as to abut on the foot switch 84, the foot switch 84 is stepped on. When the foot switch 84 is stepped on, the motor 3 for the clamp 16
4 is actuated and the clamp members 22a, 2 of the clamp 16 are
2b are brought close to each other to grip the tubular member 12. After this gripping, the motor 34 is in an overloaded state, so that the current supplied to the motor 34 becomes a predetermined value or more. The control device 80 can detect the magnitude of the current flowing through the motor 34, and if it determines that the tubular member 12 is gripped from the current value, it stops the operation of the motor 34. Thereafter, similarly, the tubular member 14 is placed on the clamp 18 so that the end surface 15 to be welded contacts the spacer 74, and the foot switch 84 is stepped on again, and the tubular member 14 is clamped between the clamp members 22a and 22b.
To hold.

When the tubular member 14 is gripped by the clamp 18, the motor 34 is stopped, and at the same time or after that, the motor 66 is activated again so that the heating body 20 moves between the end faces 13 and 15 of the tubular members 12 and 14. It is placed in the heating position. Since the plate thickness of the heating body 20 is smaller than the plate thickness of the spacer 74, the tubular member 12, which corresponds to each heating surface of the heating body 20,
A constant gap is formed between the end faces 13 and 15 of the reference numeral 14.

When the heating element 20 is thus placed in the heating position, the heat source of the heating element 20 is energized for a predetermined time.
The end faces 13, 15 of the tubular members 12, 14 are heated and melted. When the predetermined heating time has elapsed, the motor 66 is operated again, the heating body 20 and the spacer 74 are moved to the original retracted position, and the state is maintained. It is preferable to remove the cover plate 78 from the spacer body 76 before or during heating so that the spacer 74 does not interfere with the tubular members 12 and 14 during this retracting movement.

After the spacer 74 and the heating element 20 are returned to the retracted position, the motor 52 is operated and the clamp 16 is moved toward the clamp 18. As a result, the end surface 13 of the tubular member 12 held by the clamp 16 comes into contact with the end surface 15 of the other tubular member 14, and is further pressed.

By the way, even if the end faces 13 and 15 of the tubular members 12 and 14 are heated to the melting temperature or higher at the time of heating, when the retreat movement of the heating body 20 is started, the end faces 13 and 15 immediately start to cool and weld. Inappropriate non-melting state. Therefore, the time from the start of the retreat movement of the heating body 20 to the contact between the end surfaces 13 and 15 of the tubular members 12 and 14 is extremely short, preferably within 2 seconds.
More preferably, it is required to be within 1 second. Therefore, the motor 66 and the motor 52 are controlled so as to move the heating member 20 at high speed and move the tubular member 12 at high speed until the end faces 13 and 15 contact each other.

Even after the end faces 13 and 15 of the tubular members 12 and 14 are in contact with each other, the tubular member 12 is further moved by a predetermined amount, for example, 1.5 mm in the same direction at a substantially constant speed.
The moving speed at this time is switched to a low speed. After the end faces 13 and 15 of the tubular members 12 and 14 contact, penetration of the end faces 13 and 15 progresses effectively unless the speed is excessively low. Further, the end faces 1 of the tubular members 12 and 14 remain at the high speed.
It has been known from experiments and the like that the beads formed in the welded portion tend to become larger as 3 and 15 are pressed together. Therefore, although it depends on the thermoplastic resin forming the tubular members 12 and 14, the speed of the low speed movement is usually the tubular member 12 after the end faces 13 and 15 contact each other.
For most of the time it takes for the
25 mm / s to 50 mm / s, preferably 0.225 m
m / s-5 mm / s, more preferably 0.225 mm /
It is set to s-1 mm / s.

In this embodiment, the motor 52 functions as a servomotor, and the movement of the tubular members 12, 14 can be pulse-controlled. That is, the tubular member 1
Since the distance between the end faces 13 and 15 of 2 and 14 is set to be the same as the plate thickness of the spacer 74, if the motor 52 is driven by the number of pulses corresponding to the distance or plate thickness, a position detecting means is provided. Without the tubular member 12, the end face 1
It can be accurately moved at high speed until 3 comes into contact with the end surface 15 of the other tubular member 14. Regarding the movement after the end face contact, the motor 52 may be driven with the number of pulses corresponding to the amount of low-speed movement of the tubular member 12.

When the tubular member 12 is moved by a predetermined amount at a low speed, the operation of the motor 52 is stopped, and the welding portion is cooled for a predetermined time, for example, 15 seconds to 180 seconds. After the elapse of this cooling time, the motor 34 is reversely rotated and the clamp 1
The clamp members 22a, 22b of 6, 18 are separated from each other, and the tubular members 12, 14 are released from the grip. After this,
By manually removing the tubular members 12 and 14 from the welding device 10, a desired welded tubular member can be obtained.

Finally, when the reset switch 86 is pressed,
The motor 52 is activated again and the slider 48 is returned to the desired position. Then, when the slider 48 returns to the desired position, the operation of the motor 52 is stopped, and a standby state for welding the next new tubular member is performed.

Welding was actually carried out with the welding device 10 having the above-mentioned structure using a PPS pipe of model 25A manufactured by Kureha Chemical Industry Co., Ltd. and having a wall thickness of 2.4 mm, and the pipe moving speed after the end face contact was 0.5 mm / s. When the movement amount was 1.5 mm, the protrusion amount of the beads formed on the inner surface of the pipe was about 0.7 mm, and the welding strength was 65 Mpa (according to JIS K6742). Also, the movement amount is the same and the movement speed is 8 mm.
/ S, the bead protrusion amount is 1.5 mm,
The welding strength was 68 Mpa (according to JIS K6742). These can be said to be favorable results. When the moving speed was 0.1 mm / s, the welding was incomplete.

5 to 7 show a second embodiment of the welding device according to the present invention. The welding apparatus 10 of the second embodiment
0 is substantially similar to the welding device 10 of the first embodiment described above, except that the clamp is a manual type and the spacer is adapted to be manually moved along the guide rail. . Therefore, the same or corresponding parts as those of the device 10 of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The welding device 100 shown in FIGS.
Note that the lower part of 8 has been omitted.

Clamps 102, 1 of this welding apparatus 100
Both 04 include a lower clamp body 106, and an upper clamp body 108 rotatably connected to the lower clamp body 106 via a hinge mechanism 110 in the R direction shown in FIG. 7. Lower clamp body 10 of one clamp 102
6 is fixed to the slider 48, and the lower clamp body 106 of the other clamp 104 is fixed to the base 38, and both clamps 102 and 104 have substantially the same structure.

A rectangular notch is formed in the lower clamp body 106 and the upper clamp body 108 of each clamp 102, 104, and adapters 112, 114 are formed therein.
Are detachably attached. These adapters 112, 114 are provided with substantially semi-circular cutouts 113, 115 so that a substantially circular hole 116 is formed in the state shown in FIG. This hole 116
The tubular members 12 and 14 to be welded are arranged on the upper and lower ends, and when the upper and lower clamp bodies 106 and 108 are closed as shown in FIG. 7, they are gripped between the upper and lower adapters 112 and 114. The shape and diameter of the hole 116, that is, the adapter 11
The shapes and dimensions of the notches 113 and 115 of 2,114 are determined according to the cross-sectional shape and outer diameter of the tubular member to be welded. Therefore, when welding tubular members having different diameters and shapes, another adapter corresponding to the tubular member must be replaced. Further, it is preferable that the adapters 112, 114 are provided with elongated hole type screw holes (not shown), and the adapters 112, 114 are attached to the clamp bodies 106, 108 by passing screws 118 through the screw holes. By thus forming the screw holes as elongated holes, the tubular members 12 and 14 can be easily centered.

Further, each of the clamps 102 and 104 has a lock mechanism for locking and tightening the upper and lower clamp bodies 106 and 108 in the closed state shown in FIG. There are various locking mechanisms, but in this embodiment,
One end is rotatably attached to the lower clamp body 106 via the pin 120 in the P direction (FIG. 7) and can be fitted into recesses (not shown) formed on the side surfaces of the upper and lower clamp bodies 106 and 108, respectively. Rock rod 1
22 and a tightening handle 124 screwed into a threaded portion formed on the free end side of the lock rod 122. The lower clamp body 106 and the upper clamp body 108
When the lock rod 122 is erected vertically with the
The lock rod 122 is fitted in the concave portions of the clamp bodies 106 and 108, and the upper end screw portion thereof projects upward from the upper surface of the upper clamp body 108. Then, when the tightening handle 124 is screwed into this screw portion and tightened, the upper and lower clamp bodies 106 and 108 are firmly fastened to each other, and the tubular members 12 and 14 sandwiched therebetween are securely gripped.

Further, the end faces 13, 1 of the tubular members 12, 14 are
The spacer 126 that keeps the interval between the five is constant is the slider 12.
8 is attached via a support plate 130. The slider 128 is slidably attached to the guide rail 56 independently of the slider 58 of the heating element 20. No drive device is connected to the slider 128,
The movement is manual or as described later, but the slider 5 of the heating body 20
8 is performed. In the second embodiment, the heating plate 2
Electric motor 6 of drive device 62 'for moving 0
6 ', preferably a reversible AC motor, DC motor or stepping motor with a speed reducer
The driving device 62 of the first embodiment is disposed on the upper surface of the
It is easy to understand that is not functionally different from. Further, the motor 66 'and the motor 52 of the drive device 50 for moving the clamp 102 along the guide rail 46 are connected to a control device (not shown in FIGS. 5 to 7) similar to that shown in FIG. It is connected and controlled by this control device.

In the welding device 100 of the second embodiment, the tubular members 12 and 14 are welded as follows. First, the spacer 126 is manually moved and placed between the clamps 102 and 104. Next, the handle 124 is manually turned to loosen the tightening, and the lock rod 122 is turned to rotate the clamp bodies 106, 108.
Then, the clamp bodies 106 and 108 are unlocked. Then, the upper clamp body 108 is rotated away from the lower clamp body 106, and the ends of the tubular members 12 and 14 are disposed in the notches 113 of the adapter 112 of the lower clamp body 106. Then, the tubular member 1
After adjusting the positions of the tubular members 12 and 14 so that the end surfaces 13 and 15 of the rods 2 and 14 come into contact with the spacer 126, the upper clamp body 108 is rotated in the opposite direction, and the tubular member 12 and
14 is clamped between the upper and lower clamp bodies 106 and 108. In this state, attach the lock rod 122 to the clamp body 1
The tubular members 12 and 14 are fitted into the recesses of 06 and 108 and the handle 124 is tightened, so that the tubular members 12 and 14 are clamped.
Hold firmly between 6 and 108.

After that, when the start switch is pushed, the control device operates the motor 66 'to clamp the heating element 20 to the clamp 1
It is arranged at a heating position between 02 and 104. At this time, the slider 58 of the heating element 20 is the slider 128 of the spacer 126.
To move the spacer 126 to the clamps 102, 10
Return to the desired position apart from 4 spaces.

After that, the operation is performed in the same manner as in the first embodiment. In the case of the second embodiment, the tubular member 1
After heating and melting the end faces 13 and 15 of the spacers 2 and 14, the spacer 12
Since 6 does not pass between the tubular members 12 and 14,
The cover plate 78 in the spacer 74 of the first embodiment.
Is unnecessary, thus eliminating the labor required for removing the cover plate 78.

[0046]

As described above, according to the present invention, since the time from the end of heating of the end faces of the tubular member to the contact between the end faces is limited, the end faces are cooled and the state is not welded. It can be prevented from becoming appropriate. Therefore, a suitable welding result can be obtained by the subsequent pressure contact between the tubular members.

Further, after the end face contact, the tubular member is moved toward the other tubular member by a predetermined amount suitable for welding at a low constant speed, so that the size of the bead formed on the welded portion is almost the same. It will be constant.

Further, in this case, since the pressure contact pressure gradually increases, there is also an effect that the welding strength is enhanced.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a welding device according to the present invention.

FIG. 2 is a front view of the welding device shown in FIG.

3 is a side view of the welding device shown in FIG. 1. FIG.

FIG. 4 is a block diagram schematically showing a control device and its peripheral devices in the welding device shown in FIG.

FIG. 5 is a plan view showing a second embodiment of the welding device according to the present invention.

FIG. 6 is a front view of the welding device shown in FIG.

7 is a side view of the welding device shown in FIG.

[Explanation of symbols]

10, 100 ... Welding device, 12, 14 ... Tubular member, 1
6, 18, 102, 104 ... Clamp, 20 ... Heating body,
30 ... Driving device, 38 ... Base, 48 ... Slider, 50 ...
Drive device, 52 ... Electric motor, 58 ... Slider, 62 ...
Drive device, 66 ... Electric motor, 74, 126 ... Spacer, 80 ... Control device.

Claims (15)

[Claims] 1. A state in which the tubular members are coaxially held so that the end faces to be welded of a pair of thermoplastic resin tubular members are arranged so as to be opposed to each other, and the heating element is separated from each of the end faces. And arranged between the end faces, by operating the heating body to heat and melt the end face by the heat of the heating body, after the heating of the end face is completed, remove the heating body from between the end faces, the tubular One of the members is moved relative to the other tubular member in a predetermined direction to bring the end faces into contact with each other, and after the end faces are brought into contact with each other, the one tubular member is provided with respect to the other tubular member. If the one tubular member is moved by a predetermined amount with respect to the other tubular member after the end faces are brought into contact with each other, the tubular members are held stationary while being moved further in a predetermined direction. In the method for welding tubular members, The time from the heating of the end faces until the end faces are brought into contact with each other is the time at which the end faces can be prevented from being in an unsuitable state for welding, and after the end faces come into contact with each other, A method for welding tubular members, wherein the relative moving speed of the one tubular member with respect to the other tubular member is substantially constant for most of the time until the tubular member stands still. 2. The time from the completion of heating of the end faces to the contact of the end faces with each other is within 2 seconds.
A method for welding a tubular member as described above. 3. The relative movement speed of the one tubular member with respect to the other tubular member is 0.225 mm / s to 5
The method for welding a tubular member according to claim 1 or 2, wherein the welding speed is 0 mm / s. 4. The method for welding a tubular member according to claim 3, wherein the thermoplastic resin is a polyarylene sulfide resin. 5. A pair of gripping devices for respectively gripping a pair of thermoplastic resin tubular members and horizontally and coaxially holding them, and one of the gripping devices approaching the other gripping device. To heat and melt the end face to be welded of the tubular member, which is movably provided between the first drive device to be separated and the heating position between the gripping device and the retracted position away from the heating position. A heating member for driving the heating member, a second driving device for driving the heating member, and a controller for controlling the first driving device and the second driving device. The device controls the second drive device to move the heating body from the heating position to the retracted position after heating of the end surface of the tubular member gripped by the gripping device is completed; Grip one of the gripping devices to the other Means for controlling the first driving device so as to bring the end faces into contact with each other by moving the end faces relative to each other, and after the contact between the end faces, the one holding device holds the other holding device. Means for controlling the first driving device to move further relative to the device in the predetermined direction, and the one gripping device is positioned relative to the other gripping device after contact between the end faces. And a means for controlling the first driving device so as to hold both of the gripping devices stationary if they are moved by a fixed amount, until the end faces are brought into contact with each other after heating of the end faces is completed. Is the time that can prevent the end faces from becoming unsuitable for welding, and for the most part from the contact of the end faces to the rest of the gripping device, the one gripping device The other gripping device Approximately welding device constant and the tubular member relative movement speed against. 6. The time from the completion of heating of the end faces to the contact of the end faces with each other is within 2 seconds.
The tubular member welding apparatus described. 7. The relative movement speed of the one gripping device with respect to the other gripping device is 0.225 mm / s to 5
The welding device for a tubular member according to claim 5, wherein the welding device has a diameter of 0 mm / s. 8. The welding device for a tubular member according to claim 7, wherein the thermoplastic resin is a polyarylene sulfide resin. 9. The welding device for a tubular member according to claim 5, wherein the first drive device includes an electric motor. 10. The tubular member welding device according to claim 9, wherein the electric motor is a stepping motor. 11. The welding device for a tubular member according to claim 9, wherein the electric motor and the control device constitute a servo system. 12. The tubular member welding device according to claim 5, wherein the second drive device includes an electric motor. 13. The welding device for tubular members according to claim 12, wherein the electric motor is a stepping motor. 14. The welding device for a tubular member according to claim 12, wherein the electric motor and the control device constitute a servo system. 15. Each of the gripping devices can be opened and closed in a direction orthogonal to the axis of the tubular member gripped by the gripping device, and can sandwich the tubular member therebetween. 15. A pair of clamp members and a third drive device for opening and closing these clamp members are provided, and the control device is configured to control the third drive device. The welding device for a tubular member according to any one of 1.