JPH09155988A - Manufacture of resin bent pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase productivity and at the same time, enhance the shape accuracy of a bent pipe by forming a premolded straight pipe of a thermoplastic resin easily to the desired shape without the necessity to prepare a dedicated molding die for bending for each of different types of bend under an automated manufacturing system, when molding the premolded straight pipe to the three- dimensionally complicated and meandering shape. SOLUTION: The part intended for bending of a premolded pipe 6 is brought into contact with the activated part of an ultrasonic oscillator 60, and thereby is thermally softened by the ultrasonic oscillation effects. Next, a first bending roll 42A (a second bending roll 42B) is rotated in such a state that the outer peripheral face of the part to be bent is kept in contact with the first bending roll 42A (the second bending roll 42B). Finally, the part to be bent is deformed by bending along the outer peripheral face of the first bending roll 42A (the second bending roll 42B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a single pipe of a thermoplastic resin, a multi-layered pipe of a thermoplastic resin, or a bent pipe having a predetermined cross-sectional structure in which a rubber pipe is laminated on a thermoplastic resin pipe. .

[0002]

2. Description of the Related Art
For example, a bent pipe made of a resin pipe (thermoplastic resin pipe) is used for fuel supply for automobiles, and this bent resin pipe has a three-dimensional shape to form a fuel supply passage while avoiding interference with other members. It has a complicatedly meandering shape.

Conventionally, this kind of bent pipe has been manufactured as follows. That is, as shown in FIG. 8, a bending mold 200 having a bending shape corresponding to a resin bending pipe is prepared, and a preforming pipe 202 made of a resin pipe extruded into a straight pipe in advance is formed therein.
Was set in a fitting shape, put it in a heating furnace and heat-molded at a predetermined temperature for a predetermined time, then took it out of the furnace and cooled it, and then demolded to obtain a resin bent pipe. It was

However, in this case, a dedicated bending mold 200 is required for each bent resin tube, that is, for each product shape and size (thickness, etc.), and it is necessary to manufacture many products of the same type. In such a case (which is generally the case), a large number of bending molds 200 are required to increase the productivity of each product, and an extremely large number of bending molds 200 are required when producing many types of products. There was a problem that it was necessary.

Further, the preforming pipe 20 for the bending mold 200 is provided.
(2) Insertion setting work, and the work of taking out the resin bent pipe from the bending mold 200 after the heat treatment must be performed manually by the worker, and the number of steps and the amount of work for obtaining the bent pipe as a product are There was a problem that productivity increased and it increased. Further, there is a problem that the number of days for manufacturing the bending mold 200 for each product type is required, and the period required to finally obtain a resin bent pipe having a desired bent shape becomes long.

Therefore, the present applicant has proposed a method of finally obtaining a resin bent pipe having a desired bent shape by partially bending and deforming a predetermined portion of a preformed pipe of resin extruded into a straight tube. Proposed (JP-A-6-1909)
74). FIG. 9 shows an example.

As shown in the figure, according to this method, a female die 206 having a predetermined bending portion 204 is fixedly provided, while an ultrasonic oscillator 208 is provided at a position opposite to the working portion of the female die 206. It is configured as a male die 210 having a bending portion 212 corresponding to the bending portion 204, and the preforming tube 202 is sandwiched between the female die 206 and the male die 210, and then the preforming tube 202 of the preforming tube 202 is passed through the male die 210. Applying ultrasonic vibration to the bending part to heat and soften the female mold 2
06 and the male die 210 bend and deform this.

However, even in the case of this method, a dedicated bending mold is required for each product, that is, for each bent shape, and there is a problem that it is difficult to cope with products of various shapes and sizes. .

[0009]

The invention of the present application has been made to solve such a problem. Thus, the invention of the present application is a method for producing a resin bend pipe having a predetermined bend shape by bending a thermoplastic resin pipe alone or a straight tubular preformed pipe formed by laminating a rubber pipe on the thermoplastic resin pipe. That is, by applying an action part of an ultrasonic oscillating device to a predetermined bending part of the preformed tube to apply ultrasonic vibration to the heating and softening the bending part, The outer peripheral surface of the processed portion is brought into contact with the outer peripheral surface of a bending roll provided rotatably separately and independently of the ultrasonic oscillator, and by rotating the bending roll while maintaining the contact state, The bending part is bent along the outer peripheral surface of the bending roll and in accordance with the amount of rotation of the bending roll to obtain a predetermined bending shape (claim 1).

According to a still further invention of the present application, in claim 1, a pipe retainer is arranged at a position downstream of the preforming pipe in the feed direction and at a position radially opposed to the bending roll, and the preforming pipe is provided. Is bent between the pipe retainer and the bending roll, the pipe retainer is moved around the center of rotation of the bending roll together with the rotational movement of the bending roll, and the bending portion of the preforming pipe is moved. Is bent and deformed into a predetermined shape (claim 2).

In still another aspect of the present invention, in claim 2, a straight portion extending in a tangential direction is provided at a predetermined position in the circumferential direction of the bending roll, and the pipe retainer is arranged at a position facing the straight portion. However, the bending deformation is performed by the rotational movement of the bending roll while the preformed tube is sandwiched by the bending roll and the tube retainer (claim 3).

[0012]

As described above, according to the first aspect of the present invention, the working portion of the ultrasonic oscillator is applied to the preforming tube, and the predetermined bending portion is heated and softened by the action of ultrasonic vibration. , The bending roll is rotated while the outer peripheral surface of the bending portion is in contact with the outer peripheral surface of the bending roll, thereby partially bending and deforming the bending portion into a shape along the outer peripheral surface of the bending roll. Thus, according to the present invention, by appropriately controlling the rotational momentum of the bending roll, the feed of the preforming tube, and the like, it is possible to impart a desired bent shape to the bending portion.

According to the present invention, while the preformed tube is continuously or intermittently fed in the axial direction, the heating and softening by the ultrasonic wave oscillating device and the bending by the bending roll are carried out for each scheduled bending section. Therefore, the bending shape of the bending roll can be made into a desired shape by controlling the rotational momentum of the bending roll, the feeding of the preforming tube, etc. There is no need for a dedicated bending mold, and there is no need to perform the work of setting the preformed pipe to the bending mold and the work of taking out the resin bent pipe from the bending mold, resulting in a large number of resin bent pipe manufacturing processes. In addition to being able to reduce the production cost, it is possible to easily automate the production of the bent pipe, and to greatly improve the productivity.

Further, since a dedicated bending mold is not required, it is necessary to solve the problem that the time required to start the production of the bent pipe is inevitably increased by the number of days for manufacturing the bending mold. You can

In the present invention, a fitting groove for the preforming tube is provided along the outer peripheral surface of the bending roll, and the bending tube is bent along with the rotational movement of the bending roller while the preforming tube is fitted in the fitting groove. Deformation can be performed. In this case, it is possible to smoothly prevent bending of the preformed pipe and smoothly perform bending deformation while holding the preformed pipe.

It is also possible to form a fitting groove for the preformed tube in the action portion of the ultrasonic oscillator and to apply ultrasonic vibration while the preformed tube is fitted in the fitting groove. . In this case, the bent portion of the preformed pipe can be favorably heated and softened as a whole, and the bent portion of the preformed pipe can be prevented from being crushed and deformed at that time.

According to the second aspect of the present invention, the tube retainers are arranged at positions opposed to the bending rolls, and the preforming tube is sandwiched between the tube retainers and the bending rolls in the radial direction. According to the present invention, the bending portion of the preformed pipe is bent and deformed by the rotating motion. According to the present invention, the preformed pipe can be bent and deformed in a state of being well restrained by the pipe retainer and the bending roll. It is possible to improve the shape accuracy of the.

When such a tube retainer is not used, it is necessary for an operator to hold the preformed pipe against the bending roll and perform the rotational movement of the bending roll, that is, the bending deformation of the preformed pipe. However, when the preformed tube is pressed against the bending roll by such a tube presser,
There is an advantage that the work of pressing the preformed pipe against the bending roll by the operator can be omitted. It should be noted that it is preferable that a fitting groove for the preformed tube is also formed in this tube retainer, and bending deformation is performed in a state where the preformed tube is fitted inside the fitting groove.

According to a third aspect of the present invention, a straight portion extending in a tangential direction is provided at a predetermined position in the circumferential direction of the bending roll, and the preformed pipe is sandwiched by the straight portion and a pipe retainer arranged opposite thereto. In this state, the preformed tube is bent and deformed by the rotational movement of the bending roll in this state. According to the present invention, the preformed tube can be stably held in its straight portion, and thus the preformed tube accompanying the rotation of the bending roll. The bending deformation can be smoothly performed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 4 schematically show an apparatus configuration for carrying out a method for manufacturing a resin bent pipe according to an embodiment of the present invention. First, in FIG. 1, 2 is a device frame, on which a horizontal moving device 4 is arranged.

The horizontal moving device 4 includes a holding device 8 for holding a rear end portion of a straight tubular preformed pipe 6 which will be described later, and a rotary drive motor as a rotary drive means for rotationally driving the preformed pipe 6. And 10 are provided.

The horizontal moving device 4 includes a conveyor belt 12 (FIG. 2) horizontally arranged on the upper surface of the device frame 2.
And is driven by the drive motor 14 as a belt drive means, as the transport belt 12 moves forward and backward.
The horizontal moving device 4 moves forward and backward in FIG. 1 under the guidance of the guide rail 16 provided along the same direction on the device frame 2 and the sliding portion 18 fitted to the guide rail 16. It can be moved backwards.

At the front part (right side in FIG. 1) of the apparatus frame 2, an elevating plate 20 is vertically arranged so that it can be vertically moved up and down, and the elevating plate 20 is moved up and down by an air cylinder 22. It is like this.
Specifically, a connecting plate 24 is formed on the elevating plate 20 so as to project rearward in FIG. 2, and one end in the axial direction of the push rod 26 connected to the air cylinder 22 is connected to the connecting portion of the connecting plate 24. The lifting plate 20 is vertically moved based on the vertical movement of the push rod 26.

A guide bush 28 is provided on the rear surface of the elevating plate 20.
Is fitted to a guide rod 34 which is fixedly held in position by a mounting plate 30 and a holding portion 32 extending forward from the mounting plate 30 at the front portion of the device frame 2, and under the guide between the guide bush 28 and the guide rod 34. The lifting plate 20 can be moved up and down.

A support arm 36 extends forward from the front surface of the elevating plate 20 so as to project forward. With this support arm 36, a mounting table 38 is supported with respect to the support arm 36 as clearly shown in FIG. It is supported for relative rotation. The rotation axis 4 of the mounting table 38 is attached to the mounting table 38.
Above 0, the first bending roll 42A and the second bending roll 42B are concentrically provided.

The first bending roll 42A and the second bending roll 42B have a cylindrical shape, and at predetermined positions in the circumferential direction,
A straight portion 44 (see FIG. 2) extending in the tangential direction is provided. A fitting groove 46 is formed on the outer peripheral surface of the first bending roll 42A and the second bending roll 42B including the straight portion 44. The fitting groove 46 has a substantially semicircular cross-section and is sized so that the preformed pipe 6 can be fitted therein (see FIG. 3).

The first bending roll 42A and the second bending roll 42B each have a fitting groove 46 formed on the outer peripheral surface thereof.
Are different in size. That is, the first bending roll 42A and the second bending roll 42B are respectively formed with the fitting grooves 46 corresponding to the outer diameter dimensions of the preformed pipes 6 having different outer diameter dimensions, so that the lifting plate 20 is moved up and down. Thus, it is possible to select a bending roll having the fitting groove 46 that matches the outer diameter of the preformed pipe 6. Accordingly, it is not necessary to replace the bending roll with a bending roll suitable for the outer diameter of the preformed pipe 6, and the preformed pipes 6 having different outer diameters can be bent only by moving the elevating plate 20 up and down. .

The first bending roll 42 and the second bending roll 42B may have different roll diameters, that is, different minimum bending radii. In this case, when the preformed tube 6 is bent into a predetermined bending shape, the elevating plate 20 is moved up and down to select a bending roll having a bending radius suitable for the predetermined bending shape. . With this, by the up-and-down motion of the up-and-down plate 20, it is possible to select a bending roll having a predetermined bending shape without exchanging the bending roll, and it is possible to smoothly perform bending deformation processing.

As shown in FIGS. 2 and 3, the mounting table 38 also has a tube holder at a position on the upper surface thereof facing the straight portions 44 of the first bending roll 42A and the second bending roll 42B. 48 is mounted. The pipe holder 48 includes the first bending roll 42A and the second bending roll 42.
A first pressing portion 50A and a second pressing portion 50B corresponding to B are formed in a protruding shape.

The first holding portion 50A and the second holding portion 5
Fitting grooves 46 are formed at the front ends of OB, respectively. As shown in FIG. 3, the tube retainer 48 is slidably movable on the mounting table 38 from the lower right side to the upper left side in the figure by a predetermined driving means (not shown), and thus the first bending roll 42A. And first pressing portion 50A or second bending roll 4
The preformed tube 6 can be sandwiched between 2B and the second pressing portion 50B.

As shown in FIG. 1, the mounting table 38 is connected to a drive motor 54 mounted on the elevating plate 20 via a mounting bracket 52 via links 56 and 58 (see FIGS. 3 and 4). There is. At this connection,
As shown in FIG. 4, one end of the link 56 is attached and fixed so as to rotate integrally with the rotation shaft of the drive motor 54, and the other end of the link 56 has one end of the link 58. The part is rotatably mounted. The other end of the link 58 is rotatably assembled to a connecting shaft projecting downward at a predetermined position on the lower surface of the mounting table 38 as shown in FIG. .

As shown in FIG. 4, in this example, the axis of the connecting shaft is located at a position horizontally separated from the rotation axis 40 of the mounting table 38 by a predetermined distance.
Therefore, the mounting table 38 is rotated by the rotation of the drive motor 54 through the links 56 and 58 and integrally with the first bending roll 42A and the second bending roll 42B about the rotation axis 40 (FIG. 4). (See (B)).

In FIG. 2, reference numeral 60 denotes an ultrasonic wave oscillating device, which can move to a mounting base 62 fixed to the elevating plate 20 in the vertical direction in the drawing, that is, in the direction approaching or separating from the preforming tube 6. It is installed in a normal state. The ultrasonic oscillator 60 is provided with an action portion 64 that applies ultrasonic vibration to a predetermined bending portion of the preforming tube 16 to heat and soften the portion. This action part 6
A fitting groove 66 into which the preformed tube 6 is fitted is formed in the groove 4.

In FIG. 1, a cylinder 68 having a vertical axis is attached to the apparatus frame 2 in the vicinity of the attachment plate 30 on the front portion thereof. A rod 70 arranged in parallel with the cylinder 68 is attached to a movable portion of the cylinder 68.
The lower ends of are connected. On the other hand, a support bar 72 extending in the horizontal direction is attached to the upper end of the rod 70 (see FIG. 2). The support bar 72 supports the preformed pipe 6.

As is clear from the above description, in this example, the conveyor belt 12 and the drive motor 14 constitute the driving means of the horizontal moving device 4, and the elevating plate 20 provided on the front surface of the device frame 2 is used. , First bending roll 4
2A, the second bending roll 42B, and the tube retainer 48 on the mounting table 3
A lifting means for lifting and lowering with 8 is configured. Further, the drive motor 54 constitutes a rotary drive means for rotationally driving the first bending roll 42A, the second bending roll 42B and the tube retainer 48 together with the mounting table 38 around the rotation axis 40.

Further, the air cylinder 22 and the lifting plate 2
Push rod 26 and connection plate 24 provided on
, But constitutes an elevating drive means for elevating the elevating plate 20 as an elevating means. Furthermore, the guide bush 28 provided on the elevation plate 20 side and the guide rod 34 provided on the apparatus frame 2 side constitute elevation guide means for the elevation guide.

Next, the manufacturing method of this example for bending and deforming the straight tubular preformed pipe 6 into a resin bent pipe having a predetermined bent shape by using the above bending device will be specifically described below. First, the rear end of the straight tubular preformed pipe 6 cut into a predetermined length is held by the holding device 8 of the horizontal moving device 4. At this time, the support bar 72 raised by the cylinder 68 contacts the preforming pipe 6 and supports the preforming pipe 6 so that it is horizontal (see FIG. 1).

Further, as shown in FIG. 5 (I), the ultrasonic wave oscillating device 60 is located at the retracted position which is away from the preforming tube 6 in the upper direction in FIG. The mounting table 38 is located at a rotational position aligned in parallel with the longitudinal direction of the ultrasonic oscillator 60, and the tube retainer 48 on the mounting table 38 is also located at the retracted position away from the preforming tube 6. It is in a state.

The horizontal moving device 4 holding the preformed tube 6 in the above state is moved forward so that the scheduled bending portion of the preformed tube 6 is located between the first bending roll 42A and the tube retainer 48. To do. After that, as shown in Fig. 5 (II), the tube retainer 4
8 and the ultrasonic wave oscillating device 60 advance toward the preforming tube 6, respectively.

As the tube retainer 48 advances, the preformed tube 6 is fitted into the insertion groove 46 formed at the tip of the first retainer portion 50A, and the tube retainer 48 further advances, so that the preformed tube 6 is formed. The first bending roll 42A is fitted into the fitting groove 46 formed in the straight portion 44. In this way, the preformed tube 6 is sandwiched in the radial direction by the first pressing portion 50A and the first bending roll 42A.

On the other hand, as the ultrasonic oscillator 60 moves forward, the bent portion of the preformed pipe 6 is fitted into the fitting groove 66 formed in the acting portion 64 thereof. In this state, ultrasonic vibration is applied from the acting portion 64 to the preformed pipe 6 in the fitting groove 66 to heat the bending portion of the preformed pipe 6.

When the bending portion of the preforming tube 6 is heated by the action of the ultrasonic vibration by the ultrasonic oscillating device 60 and is softened to a predetermined hardness, the driving motor 54 is driven next and the links 56 and 58 are connected. The rotational drive of the drive motor 54 is transmitted to the mounting table 38 via the drive. Then, together with the mounting table 38, the first
The bending roll 42A rotates so that the bending portion of the preforming tube 6 has a predetermined bending angle (see FIG. 6 (III)). At this time, the first pressing portion 50A and the first bending roll 4
The straight section 44 of 2A rotates together with the mounting table 38 in a state where the preformed tube 6 is sandwiched between them, and the first bending roll 4
With the rotation of 2 A, the preforming tube 6 is moved to the first bending roll 42.
A will be bent along the inside of the fitting groove 46 on the outer peripheral surface.

On the other hand, the horizontal moving device 4 includes the first bending roll 4
The forward movement is performed by a length corresponding to the bending radius and the bending rotation angle of 2A. That is, the preforming tube 6 in the bending deformation processing portion is sent by the horizontal moving device 4 by sending out the preforming tube 6 as needed in response to the rotation of the first bending roll 42A.
Avoids crushing deformation. Further, in the ultrasonic oscillator 60, while the preforming tube 6 is fitted inside the fitting groove 66 of the acting portion 64, the preforming tube 6 is sent out at any time as the first bending roll 42A rotates. Ultrasonic vibration is applied to heat and soften it.

When the first bending roll 42A is rotated to the predetermined bending angle of the preforming tube 6, the ultrasonic oscillating device 60 stops the oscillation of ultrasonic vibration. After the heat-softened preformed tube 6 is cooled and hardened, the tube retainer 48 and the ultrasonic oscillator 60 are moved backward as shown in FIG. 6 (IV).

Then, as shown in FIG. 7 (V), the mounting table 3
5 returns to the position of FIG. 5 (I), the horizontal moving device 4 moves forward to the next scheduled bending portion of the preforming pipe 6. At this time, in the case of a bent pipe which is bent three-dimensionally, the preforming pipe 6 is rotated by a predetermined angle in the circumferential direction by the rotary drive motor 10 in the horizontal moving device 4. According to the above, one bending step in the manufacturing process of the resin bent tube is performed, and the bending step is repeated according to the number of planned bending portions to form a bent tube having a predetermined shape.

In this example, the first bending roll 42A
However, the same procedure can be applied to the case where the second bending roll 42B and the second pressing section 50B are used. In addition, when the roll diameters of the first bending roll 42A and the second bending roll 42B are different, a bending roll suitable for each bent shape of the resin bent pipe is selected by the lifting motion of the lifting plate 20 while predetermined. It is also possible to process into a bent resin bent pipe.

According to this embodiment, the ultrasonic wave oscillating device 6 is fed while the preformed pipe 6 is continuously or intermittently fed in the axial direction.
The heating and softening by 0 and the bending by the first bending roll 42A or the second bending roll 42B can be performed for each of the scheduled bending portions. Therefore, the first bending roll 42A
And the bending shape by the second bending roll 42B is the first
Since a desired shape can be obtained by controlling the rotational momentum of the bending rolls 42A and the second bending rolls 42B, the feed of the preforming tube 6, etc., a dedicated bending mold for each bending shape is required as in the conventional method. In addition, there is no need to perform the work of setting the preformed pipe 6 in the bending mold and the work of taking out the resin bent pipe from the bending mold, which can greatly reduce the number of manufacturing steps of the resin bent pipe and The automation of the production of the pipe can be easily achieved, and the productivity can be greatly increased.

Further, since a dedicated bending mold is not required, it is necessary to solve the problem that the time required to start the production of the bent pipe is inevitably increased by the number of days for manufacturing the bending mold. You can

In this embodiment, the first bending roll 4
The first bending roll 42A and the second bending roll 42A and the second bending roll 42A and the second bending roll 42B are provided with the fitting groove 46 of the preforming pipe 6 provided along the outer peripheral surfaces thereof, and the preforming pipe 6 is fitted inside the fitting groove 46. The roll 42 </ b> B is bent and deformed in accordance with the rotational movement of the roll 42 </ b> B, so that the preformed pipe 6 can be smoothly prevented from being crushed and the preformed pipe 6 can be smoothly held and bent. it can.

Further, in the operating portion 64 of the ultrasonic oscillator 60,
The fitting groove 66 of the preforming pipe 6 is formed, and ultrasonic vibration is applied in a state where the preforming pipe 6 is fitted inside the fitting groove 66. In this case, bending of the preforming pipe 6 is performed. It is possible to heat and soften the whole part well,
At that time, it is possible to prevent the bending portion of the preformed pipe 6 from being crushed and deformed.

Further, according to this embodiment, the first bending roll 4
The tube retainer 48 is arranged at a position facing the 2A and the second bending roll 42B, and the first retaining portion 5 corresponding to the first bending roll 42A and the second bending roll 42B is disposed on the pipe retainer 48.
0A, the second pressing portion 50B is provided, the first pressing portion 5
0A and the first bending roll 42A, or the second pressing portion 50B and the second bending roll 42B, the first bending roll 4 with the preforming pipe 6 sandwiched in the radial direction.
The bending portion of the preforming tube 6 is bent and deformed by the rotational movement of the second bending roll 42B and 2A. Therefore, the preformed tube 6 is attached to the first pressing portion 50A and the first bending roll 4
2A or the second pressing portion 50B and the second bending roll 42B can be bent and deformed in a well-restrained state, and the bending shape accuracy can be improved. In addition, there is an advantage that the work of pressing the preforming pipe 6 against the first bending roll 42A or the second bending roll 42B by the operator can be omitted.

Further, the fitting groove 46 of the preforming pipe 6 is formed in each of the first holding portion 50A and the second holding portion 50B, and by inserting the preforming pipe 6 into the fitting groove 46, 1st pressing part 50A and 1st bending roll 42A or 2nd pressing part 50B and 2nd bending roll 42B
The pre-molded tube 6 is prevented from being pinched by the above.

The embodiment of the present invention has been described in detail above, but this is merely an example, and the present invention can be applied to other uses and types of bent resin pipes. Further, the present invention can be applied to a thermoplastic resin single pipe, a laminated pipe of thermoplastic resin, or a resin bent pipe having a cross-sectional structure in which rubber or the like is laminated on a thermoplastic resin pipe. The present invention can be implemented with various modifications without departing from the scope.

[Brief description of the drawings]

FIG. 1 is a front view showing an outline of an apparatus for carrying out a method for manufacturing a bent resin tube according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view of a main part including a bending roll and an ultrasonic oscillator in the apparatus of FIG.

FIG. 3 is an enlarged right side view of FIG.

FIG. 4 is an operation explanatory view showing the rotational movement of the bending roll in the apparatus of FIGS. 1 to 3;

FIG. 5 is an explanatory view for explaining the manufacturing procedure of the resin bent pipe which is one embodiment of the present invention, using the apparatus shown in FIGS.

FIG. 6 is an explanatory view illustrating a procedure for manufacturing the resin bent pipe continued from FIG. 5;

FIG. 7 is an explanatory view illustrating a procedure for manufacturing the bent resin tube continued from FIG. 6;

FIG. 8 is a diagram showing a conventional method for manufacturing a bent resin pipe.

FIG. 9 is a view showing another conventional method for manufacturing a resin bent pipe different from that shown in FIG.

[Explanation of symbols]

 6 Preformed Tube 42A First Bending Roll 42B Second Bending Roll 44 Straight Section 46, 66 Fitting Groove 48 Pipe Pressing 50A First Pressing Section 50B Second Pressing Section 60 Ultrasonic Oscillator 64 Working Section

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29K 101: 12 B29L 9:00 23:00

Claims (3)

[Claims] 1. A method for producing a resin bend pipe having a predetermined bend shape by subjecting a straight pipe preformed pipe formed by laminating a thermoplastic resin pipe alone or a rubber pipe to the thermoplastic resin pipe to a bending process. The bending portion of the preformed tube is heated and softened by applying an ultrasonic vibration to the bending portion of the preformed tube, and the outer circumference of the heating and softened bending portion. The bending surface is brought into contact with the outer circumferential surface of a bending roll provided rotatably separately and independently of the ultrasonic oscillator, and the bending roll is rotationally moved while maintaining the contact state. Is bent along the outer peripheral surface of the bending roll and in accordance with the amount of rotation of the bending roll to obtain a predetermined bent shape. 2. The pipe retainer according to claim 1, wherein a pipe retainer is arranged at a position downstream of the preformed pipe in a feed direction and at a position opposed to the bending roll in a radial direction, and the preformed pipe is provided with the pipe retainer. In a state of being sandwiched with the bending roll, the pipe retainer is moved around the rotation center of the bending roll together with the rotational movement of the bending roll to bend and deform the bending portion of the preforming pipe into a predetermined shape. A method for manufacturing a bent resin tube, which comprises: 3. A straight portion extending in a tangential direction at a predetermined position in the circumferential direction of the bending roll, while the pipe retainer is arranged at a position facing the straight portion.
A method for producing a resin bent pipe, characterized in that bending deformation is carried out by rotational movement of the bending roll while the preformed pipe is sandwiched by the bending roll and the pipe retainer.