JP2759682B2 - Curved pipe manufacturing method and bent pipe manufacturing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a rubber tube containing a reinforcing material such as a mesh, a metal tube, or a tube made of a thermoplastic material.
The present invention relates to a bent pipe manufacturing method and a bent pipe manufacturing apparatus which are formed into a bent pipe having various curves by extrusion.

(Prior Art) Conventionally, a conventional method of manufacturing a curved pipe is as follows: first, an extruder is used to extrude a straight pipe material, and then the extruded material is formed into a desired bent shape to substantially fit the inner diameter of the straight pipe blank. After passing through a mandrel of close dimensions and performing a habit, it is extracted from this mandrel to make a product, or the straight tubular material is pressed into a mold composed of an outer mold and a middle mold having a desired shape, and the hammered After that, the middle mold is taken out as a product, or a material is injected using only the outer mold, and is manufactured by an inflation method or the like in which a pressurized fluid such as air, gas, or liquid is sealed.

On the other hand, JP-A-59-123636 proposes a method and apparatus for manufacturing a bent pipe.

This manufacturing method and apparatus include a die and a core for extruding a tubular body, forming the die or the core so as to be movable in a lateral direction with respect to the extrusion direction, and driving a servo motor according to a program. Use a device that can control the movement of the die or core via the drive rod by controlling the rotation, and move the die or core to make the gap between the die and the core uniform throughout the circumference. Alternatively, a straight pipe portion or a bent portion is formed by making it uneven.

(Problems to be Solved by the Invention) However, the former method is inferior in workability due to manual work and a large number of steps, and the outside of the bent portion becomes thin due to bending of a straight tubular material, so that a processing liquid or the like is used. When used in this way, there is a risk of rupture from this thin part, and the aging of the mold and core metal may cause variations in the product, and the core metal and mold must be formed with the bent shape, respectively. In addition, there is a problem that the cost of producing the core metal, the mold, and the like is high and the economic efficiency is inferior.

Further, the latter device has been proposed to solve the former problem, but a kneaded material is extruded from a gap between the die and the core bar, and at that time, the die or the core bar is moved to move the die and the core bar. This device is used to form straight pipes or bent parts by making the gap with gold uniform or non-uniform on the entire circumference. Use this device for rubber pipes containing reinforcing materials such as mesh. There was a drawback that molding was impossible.

In addition, when forming curved tubes of all shapes that change three-dimensionally, each die is separately formed in a direction intersecting at a desired angle with respect to the lateral direction corresponding to each angle of the three-dimensional shape to be formed. Alternatively, a plurality of driving rods are provided so that the core moves, and the driving rods are operated. Therefore, it becomes very complicated mechanically,
When transmitting the driving force, the backlash of the transmission mechanism adversely affects the movement of the core metal, which requires very accurate operation.

In view of the above-mentioned problems and the like, the present invention provides a rubber tube containing a reinforcing material such as a mesh, or a metal tube, or a tube made of a thermoplastic material, using a metal core or a mold each having a bent shape. The object of the present invention is to make it possible to form as a bent tube of any curve by extrusion without the need for a tube.

(Means for Solving the Problems) In the present invention, as a method for manufacturing a bent pipe, a rubber pipe containing a reinforcing material such as a mesh, which has been previously molded as an unvulcanized straight pipe, is used, and this straight pipe is forcibly formed. By passing through the tubular gap of the extrusion port by extrusion, at that time, the gap width of the annular gap is appropriately changed from an equal width by two concentric circles to an uneven width by two circles having different centers, as described above. In addition, as a method for manufacturing a bent pipe, a metal pipe or a pipe made of a thermoplastic material, which is previously formed as a straight pipe, is used, and the straight pipe is heated until it becomes a plastic state. While passing through the annular gap of the extrusion port by forced extrusion,
At that time, the above-mentioned problem is solved by appropriately changing the gap width of the annular gap from an equal width by two concentric circles to an uneven width by two circles having different centers. As an apparatus, an extruded tube forming section for forcibly extruding a rubber tube containing a reinforcing material such as a mesh, a metal tube, or a tube made of a thermoplastic material from an annular gap, and forming the extruded tube. A heat retaining device disposed at least in the vicinity of the extruding port of the portion and heating the tube so as to keep the tube in a plastic state. A delivery guide body that fits outside with the same annular gap, and a push-out port that fits outside with a predetermined annular gap at the tip of the metal core, and is formed with respect to the center axis of the metal core. It is formed so that it can be moved appropriately in the direction of the orthogonal plane. An extrusion die, and an extrusion tube for pushing the tube toward the extrusion port from the opposite side of the extrusion port when the tube is externally fitted to the cored bar and pushed into the annular gap between the delivery guide. The movement of the extrusion die and the pushing of the extrusion tube are performed through a backlash-free reduction gear to solve the above-mentioned problem. A worm reduction device comprising a drum-shaped worm and a disk device rotating about an axis orthogonal to the longitudinal axis of the worm at a distance from the worm and cooperating with the worm. A roller device arranged at intervals to match the pitch of the worm groove and always formed to press the roller in the direction of the worm, and each roller device can rotate a plurality of rollers. The above-mentioned problem is solved by being formed so as to be pivotally engaged with the worm.

(Function) In the method of manufacturing a bent tube according to the present invention, in the case of a rubber tube containing a reinforcing material such as a mesh, first, a rubber tube containing a reinforcing material is previously formed as an unvulcanized straight tube. Using a straight pipe, this straight pipe is passed through the annular gap of the extrusion port by forced extrusion, and at that time, the gap width of the annular gap is changed from an equal width by two concentric circles to an uneven width by two circles having different centers. Change the width appropriately. In this case, the material having a large gap has a small extrusion resistance, so that the material is extruded quickly. On the other hand, the material having a small gap has a large extrusion resistance, so that the material is extruded later. As a result, the tube with the larger gap becomes the outer side of the curve and the tube is formed in a bent state, and the wall thickness at that time is such that the outer side of the curve is thicker and the inner side of the curve is thinner.

In the case of a metal tube or a tube made of a thermoplastic material, use a tube which has been previously formed as a straight tube, and forcibly keep the straight tube heated until it becomes a plastic state. By passing through the annular gap of the extrusion port by extrusion,
At that time, the gap width of the annular gap is appropriately changed from a uniform width by two concentric circles to an uneven width by two circles having different centers. Then, since the straight pipe itself is heated and is in a plastic state, as described above, the side where the gap is wide is extruded quickly because the extrusion resistance is small, and conversely, the side where the gap is narrow is The material is extruded late because of the increased extrusion resistance. As a result, the tube with the larger gap becomes the outer side of the curve and the tube is formed in a bent state, and the wall thickness at that time is such that the outer side of the curve is thicker and the inner side of the curve is thinner.

The operation of the device at that time is as follows. First, a rubber tube containing a reinforcing material such as a mesh is attached to the core metal of the extruded bent tube forming portion,
Alternatively, a metal tube or a tube made of a thermoplastic material is externally fitted and inserted into an annular gap between the cored bar and the delivery guide body. Then, afterwards, the tube is pushed into the extrusion port from the side opposite to the extrusion port by the extrusion cylinder, and at that time, the extrusion port die is appropriately moved in the direction of the surface orthogonal to the central axis of the core metal at the extrusion port. Move. Then, the gap between the extrusion die and the core metal is appropriately changed from an even width by two concentric circles to an uneven width by two circles having different centers. As a result, as described above, the tube having the larger gap becomes the curved outer side and the pipe is formed in a bent state, and the wall thickness at that time is thicker on the outer side of the curve and thinner on the inner side of the curve.

In addition, the extruded tube is heated by a heat retaining device arranged at least in the vicinity of the extruding port of the extruded tube forming section to keep the tube in a plastic state and to make the extruded tube extrudable.

On the other hand, the movement of the extrusion die and the pushing of the extrusion cylinder at this time are performed through a speed reducer without backlash,
Power transmission is performed continuously without stagnation.

This backlash-free speed reducer rotates the hourglass worm and the disc device about an axis spaced and orthogonal to the longitudinal axis of the hourglass worm, thereby cooperating with the worm. At that time, a plurality of rollers, each of which is rotatably arranged by being fixed to a roller device arranged at intervals so as to match the pitch of the groove of the worm on the periphery of the disc device, are arranged at that time. The worm is always pressed in the direction of the worm to mesh with the worm, and the rotation of the roller enables meshing without backlash.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

That is, in the process chart shown in FIG.
For example, an unfinished pipe in which a reinforcing layer 2 as a reinforcing material such as a mesh is embedded in a rubber material (hereinafter referred to as “braid” in the examples) and the reinforcing layer 2 is contained in a plastic state before vulcanization. First, as shown in FIG. 1 (B), first, the unfinished straight pipe 1 shown in FIG. 1 (A) is passed through the annular gap 4 of the extrusion port 3 by forced extrusion. Mandrel
The gap width of the annular gap 4 formed by the extrusion die 12 and the extrusion die 14 is appropriately changed from an equal width by two concentric circles to an uneven width by two circles having different centers.

Then, on the side where the gap 4 is wide, the material is extruded quickly because the extrusion resistance is small, and conversely, on the side where the gap 4 is narrow, the material is extruded slowly because the extrusion resistance is large. As a result, as shown in FIG. 1 (C), the unfinished pipe 1 is formed into a bent state with the wide side of the gap 4 being curved outside, and the wall thickness at that time is also thick at the curved outside. ,
The inside of the curve becomes thinner.

After that, the unfinished pipe 1 extruded from the extrusion port 3 is vulcanized to complete.

As shown in FIG. 2, the bent pipe manufacturing apparatus used at that time is an unvulcanized unfinished pipe 1 of a reinforcing layer-containing pipe in which a reinforcing layer 2 such as a mesh is braided in a rubber material, and is formed into an annular gap. 4
Bent tube forming section 11 forcibly extruded from the pipe, and a heat retaining device which is provided at least in the vicinity of the extrusion opening 3 of the bent bent tube forming section 11 and is heated so as to maintain the unfinished pipe 1 in a plastic state. It consists of 15. In addition, this heat retention device 15
In the case of a rubber tube containing a reinforcing layer such as a mesh, it is not so necessary. However, in the case of a metal tube to be described later, or in the case of an unfinished tube 1 made of a thermoplastic material, it is necessary to heat it. It is.

The extruded bent tube forming portion 11 includes a cored bar 12, a delivery guide body 13 that fits over the cored bar 12 with an annular gap 11 a substantially equal to the thickness of the unfinished tube 1, and a cored bar 12. An extrusion die 3 is formed by externally fitting to have a predetermined annular gap 4 at the tip end portion of the metal core 12 to form the extrusion port 3 and movably in a direction perpendicular to the central axis of the cored bar 12. When the unfinished pipe 1 is externally fitted to the cored bar 12 and pushed into the annular gap 11a between the core guide 12 and the delivery guide 13, the unfinished pipe 1 extends from the side opposite to the extrusion port 3 toward the extrusion port 3. And an extruding cylinder 16 for pushing the cylinder 1 into.

As shown in FIG. 3, the extrusion die 14 is movably arranged in a two-dimensional manner by a sliding portion 18 disposed around the extrusion die 14, and the extrusion die 14 is provided with a motor. The screw rod 19 is pushed and pulled through a backlash-free speed reducer 31 that reduces the driving rotational force of the core 32, and the screw rod 19 is pushed and pulled as appropriate in the vertical and horizontal directions, so that the core 12 is oriented in a direction perpendicular to the axis of the core 12.
The extrusion die 14 is moved two-dimensionally as needed. Further, the screw rod 19 is pushed and pulled by a female screw (not shown) screwed into the screw rod 19 at the center of the disk device 24 shown in FIG. The screw rod 19 is screwed into the female screw, and the screw rod 19 is
Are formed so as not to rotate, and the disk device 24 is rotated forward and reverse.

On the other hand, the cored bar 12 is located behind the extruded tube forming section 11 in the delivery guide body 13 with an annular gap substantially equal to the wall thickness of the unfinished tube 1 as described above. The portion which is fixed and is exposed rearward from the portion of the delivery guide body 13 is formed thin, for example, so that the unfinished tube 1 can be easily fitted to the metal core 12.

The push-out tube 16 is inserted into the gap 11a of the bent tube forming portion 11 so as to fit the unfinished tube 1 from the side opposite to the push-out port 3 of the delivery guide body 13, that is, from behind. And a screw portion 17 is engraved on the outer periphery. The pushing movement of the extrusion cylinder 16 at this time is formed so as to be performed by the drive of the motor 22 via the speed reducer 21 without backlash.

As shown in FIG. 2, the structure is such that a female screw which is screwed into the screw portion 17 of the extrusion cylinder 16 is engraved at the center of a disk device 24 as an output side rotating body of the speed reducer 21. The screw unit 17 is screwed into the female screw and the extrusion cylinder 16 is formed so as not to rotate, and the disc device 24 is rotated forward and reverse.

The structure of the speed reducer 21 and the speed reducer 31 is, as shown in FIG. 4, a so-called hindley worm 23 provided with a helical engagement groove 26 provided around the periphery of the drum-shaped member, and It rotates about an axis orthogonal to the longitudinal axis of the drape worm 23 at intervals, and a roller arrangement groove 28 having an interval and an angle corresponding to the pitch of the engagement groove 26 is provided on the periphery thereof. It comprises a disk device 24 cooperating with 23 and a roller device 25 arranged in a roller arrangement groove 28 on the periphery of the disk device 24.

The roller device 25 has a plurality of, in the illustrated, two rollers 27 rotatably supported on a shaft support 29 and is disposed in a roller arrangement groove 28.
27 is formed by pressing the shaft support 29 in the direction of the hindley worm 23 by the roller pressing spring 30 so as to press the roller 27 against the mesh groove 26 so that each roller device 25 and the hindley worm 23 mesh with each other. It is. Further, the shaft support 29 is formed so as to be able to rotate by a slight angle, and is formed so as to correspond to a change in the angle of the engagement groove 26 of the hinge worm 23.

Therefore, if the speed reducers 21 and 31 formed as described above are used, there is no backlash because the roller device 25 is constantly pressed toward the meshing groove 26 of the hinged worm 23. Without this, meshing deceleration was not possible, but since the roller 27 rotates, deceleration without backlash is possible.

On the other hand, as another embodiment, the material of the unfinished pipe 1 is
For example, it is a case where a metal or a thermoplastic material is used.

In this case, the heat retaining device 15 built in the delivery guide body 13 works effectively, and the core metal 12 of the extrusion port 3 and the extrusion port die
Before the unfinished pipe 1 passes through the gap 4 with the pipe 14, the unfinished pipe 1 made of metal or a thermoplastic material is heated to a plastic state, and then the gap 4 of the extrusion port 3 is filled in the above-described embodiment. The bent pipe is formed by passing the unfinished pipe 1 in the same manner as described above.

It goes without saying that the present invention is not limited to the above-described embodiment.

(Effects of the Invention) The present invention configured as described above uses a rubber tube 1 containing a reinforcing material such as a mesh, which has been molded as an unvulcanized straight tube in advance, and extrudes the straight tube by forced extrusion. 3 through the annular gap 4, at which time the annular gap 4
The gap width of the gap 4 is appropriately changed from a uniform width by two concentric circles to an uneven width by two circles having different centers, so that the side where the gap 4 is widened has a small extrusion resistance, so that the material is quickly extruded. Conversely, on the side where the gap 4 becomes narrower, the material is extruded later because the extrusion resistance increases. As a result, the tube 1 is formed into a bent state with the side where the gap 4 is wider as the outside of the curve, and the wall thickness at this time is such that the outside of the curve is thick and the inside of the curve is thin.

Therefore, unlike the related art, there is no need for a mold having an outer mold and a middle mold having a desired shape, and the method and apparatus for manufacturing a bent pipe proposed in Japanese Patent Application Laid-Open No. 59-123636 are not required. The rubber tube 1 containing a reinforcing material such as a mesh, which could not be formed as a bent tube, can be formed as a bent tube. Cost reduction,
Since the capital investment is small, an inexpensive bent pipe can be provided. Moreover, the bent tube formed at that time is
Since the thickness on the outside of the curve is increased, the pressure resistance is excellent.

On the other hand, a metal tube or a tube 1 made of a thermoplastic material
In this case, the pipe 1 is formed as a straight pipe in advance, and the straight pipe is passed through the annular gap 4 of the extrusion port 3 by forcible extrusion while being heated until it becomes a plastic state. In addition, by appropriately changing the gap width of the annular gap 4 from an equal width by two concentric circles to an uneven width by two circles having different centers, a bent pipe can be easily formed, and the mesh of the mesh can be easily formed. The same effect as in the case of the rubber tube 1 containing the reinforcing material is exerted.

In addition, as a device used at that time, a rubber tube 1 containing a reinforcing material such as a mesh, a metal tube, or a tube 1 made of a thermoplastic material is forcibly extruded from an annular gap 4. Tube forming section 11 and this extruded bent pipe forming section
A heat retention device 15 disposed at least in the vicinity of the extrusion port 3 and for heating the tube 1 to keep it in a plastic state;
The extruded bent tube forming portion 11 includes a cored bar 12, a delivery guide body 13 that fits around the cored bar 12 with an annular gap 11 a substantially the same as the thickness of the tube 1, and a tip of the cored bar 12. An extrusion die 14 formed externally so as to have a predetermined annular gap 4 at the portion to form the extrusion port 3 and formed so as to be appropriately movable in a direction perpendicular to the central axis of the cored bar 12; When the pipe 1 is externally fitted to the cored bar 12 and pushed into the annular gap 11a between the pipe 1 and the delivery guide body 13, the pipe 1 is pushed from the side opposite to the extrusion port 3 toward the extrusion port 3. It is composed of a cylinder 16 and the movement of the extrusion die 14 and the pushing of the extrusion cylinder 16 are performed through the speed reducers 21 and 31 without backlash. Even if it is a rubber tube 1 or a metal tube or a tube 1 made of a thermoplastic material, all the three The bent pipe having original bend can be easily formed. What is particularly important is that the use of a speed reducer without backlash ensures that the movement of the extrusion die 14 with respect to the metal core 12 and the pushing of the extrusion cylinder 16 are accurate and uniform, so that the unfinished pipe is not used. 1 can be accurately extruded, whereby a uniform curved state can be exhibited, and thus, a bent tube can be reliably formed.

And the speed reducer without backlash at that time 21, 31
In a worm speed reducer comprising a drum-shaped worm 23 and a disk device 24 that rotates about an axis orthogonal to the longitudinal axis of the worm 23 at a distance from the worm 23 and cooperates with the worm 23, On the periphery of the plate device 24, there are provided roller devices 25 arranged at intervals so as to match the pitch of the grooves 26 of the worm 23 and formed so as to always press the roller 27 in the direction of the worm 23. Since each of the plurality of rollers 27 is rotatably supported and formed to mesh with the worm 23, the roller device 25 is constantly pressed toward the groove 26 of the drum-shaped worm 23, so that the backlash Although there was no backlash, meshing and deceleration were originally impossible without backlash, but since the roller 27 rotates, deceleration without backlash is possible.

As described above, according to the present invention, a rubber tube containing a reinforcing material such as a mesh, or a metal tube, or a tube made of a thermoplastic material can be formed without the need for a core metal or a mold associated with a bent shape. It can be formed as a bent tube of any curve by extrusion.It is suitable for both low-volume production and mass production, and can provide an inexpensive bent tube. Various excellent effects such as a great reduction in capital investment can be achieved.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, wherein FIG. 1 is a process diagram, FIG.
FIG. 4 is a schematic front sectional view of an essential part, and FIG. 4 is an enlarged view of a partially cut-away essential part of a speed reducer without backlash. 1 ... unfinished pipe, 2 ... reinforcement layer, 3 ... extrusion port, 4 ...
… Gap, 11… Extrusion bent tube forming part 11, 12… Core metal, 13… Sending guide body, 14… Extrusion die, 15… Heat retaining device, 16…
… Extrusion tube, 17… Screw part, 18… Sliding part, 19 …… Screw rod, 20… Protective bellows, 21 …… Reducer, 22 …… Motor, 23 …… Hindley worm, 24 …… Disk device, 25 ... Roller device, 26 ... Meshing groove, 27 ... Roller, 28 ... Roller arrangement groove, 29 ...
... Axle support, 30 ... Roller pressing spring, 31 ... Reducer, 32 ... Motor.

Claims (4)

(57) [Claims] 1. A rubber tube containing a reinforcing material such as a mesh, which has been previously molded as an unvulcanized straight tube, is used, and this straight tube is passed through an annular gap of an extrusion port by forced extrusion. A method of manufacturing a bent pipe, wherein the width of the annular gap is appropriately changed from a uniform width by two concentric circles to an uneven width by two circles having different centers. 2. A metal pipe or a pipe made of a thermoplastic material, which has been molded as a straight pipe in advance, and while the straight pipe is being heated to a plastic state, it is heated and forcedly extruded to form a ring at an extrusion port. Wherein the gap width of the annular gap is appropriately changed from an equal width by two concentric circles to an uneven width by two circles having different centers at that time. 3. An extruded tube forming section for forcibly extruding a rubber tube containing a reinforcing material such as a mesh, a metal tube, or a tube made of a thermoplastic material from an annular gap. A heat retention device disposed at least near the extrusion opening of the tube forming portion and heating the tube to keep the tube in a plastic state; the extruded bent tube forming portion includes a cored bar; A feed guide body which is fitted around with a substantially same annular gap as the above, and a push-out port which is fitted around the leading end of the core with a predetermined annular gap, and is formed on the center axis of the core. An extrusion port die formed so as to be movable as appropriate in the direction perpendicular to the surface, and when the tube is externally fitted to a cored bar and pushed into an annular gap between the delivery guide, from the opposite side of the extrusion port. An extrusion tube for pushing the tube toward the extrusion port. Moving, and, pushing the extrusion barrel,
A bent pipe manufacturing apparatus characterized in that it is formed to be performed through a speed reducer without backlash. 4. A speed reducer without backlash comprises a drum-shaped worm and a disk device which rotates about an axis perpendicular to and spaced from the longitudinal axis of the worm and cooperates with the worm. In the worm reduction gear device, a roller device is provided on the periphery of the disc device at intervals so as to match the pitch of the groove of the worm, and a roller device formed so as to always press the roller in the worm direction is provided. 4. The bent pipe manufacturing apparatus according to claim 3, wherein each of the plurality of rollers is rotatably supported so as to be engaged with the worm.