JPH027738B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for increasing the thickness of a tube, and more particularly to a method and apparatus for increasing the thickness of a tube with the aim of uniformly increasing the thickness of the tube.

Conventionally, as a method for increasing the thickness of a tube, a method is known in which swaging is performed by applying compressive force in the axial direction of the tube to increase the thickness of the tube.

FIG. 1 is a perspective view showing a tube whose thickness has been increased by a conventional method of increasing its thickness.

In this FIG. 1, 1 is a pipe, and 2 is this pipe 1.
Irregular deformations such as buckling and wrinkles that occur in

As is clear from Fig. 1, if the swaging process is performed only by applying compressive force, that is, by simple compression process, irregular deformation 2 such as buckling and wrinkles will occur in the tube 1, resulting in uniform thickening. Processing could not be achieved and this was the cause of defects.

The present invention provides a method for increasing the thickness of a pipe, which eliminates the drawbacks of the prior art described above and achieves uniform thickness increasing without irregular deformations such as buckling and wrinkles, and a method that can be used directly to implement this method. Its purpose is to provide a device that can

The structure of the method for increasing the thickness of a pipe according to the present invention is to perform swaging by applying a compressive force to compress the tube at a constant speed while sequentially locally heating the portion of the tube to be increased. By doing so, the thickness of the thickened portion is increased.

Further, the structure of the thickening processing apparatus according to the present invention includes: a stepping cylinder capable of compressing a tube in the axial direction at a constant speed with its spindle; The tube is provided with an annular heating coil that is movable along the axial direction of the tube.

Before entering into the description of the embodiments, basic matters related to the method of increasing the thickness of a pipe according to the present invention will be explained.

When thickening a pipe, simple compression processing requires
Since the deformation progresses throughout the tube, irregular deformations such as buckling and wrinkles are likely to occur as described above.

In order to prevent this irregular deformation, the method for increasing the thickness of a tube according to the present invention locally heats the portion of the tube to be increased, that is, the area to be increased, and the heating position is set in the axial direction of the tube. A compressive force that compresses the tube at a constant speed is applied while moving the tube sequentially along the tube, and the local heating narrows the region in which the tube is deformed by the compressive force. By narrowing the deformation region in this way (for example, narrowing it to less than twice the thickness of the tube), it is possible to prevent the irregular deformation and achieve uniform thickening.

Hereinafter, the present invention will be explained with reference to Examples.

FIG. 2 shows an example of a pipe wall-thickening processing device used to carry out a pipe wall-thickening processing method according to an embodiment of the present invention, and a pipe to be wall-thickened by the same. FIG.

In this FIG. 2, 1 is a pipe to be thickened, 4 is a pressbed provided with a positioning part 4a for positioning one end of the pipe 1, and 3 is a pressbed on its side (left side in FIG. 2). A plate 5 to which a stepping cylinder 6, which will be described later, is attached.
a, 5b are the plate 3 and press bed 4;
are fixed at opposite positions separated by a predetermined distance, and can receive the reaction force of the compressive force, which will be described later. Further, the pillar 5b is connected to a transformer 12 which will be described later.
It also serves as a guide for the axial movement of.

Reference numeral 13 denotes an annular heating coil that is disposed around the outer periphery of the tube 1 and can heat the tube 1. It is movable along one side of its inner diameter surface (of the heating coil 13,
Injection ports 13a for injecting a portion of the cooling water 14 for cooling the heating coil toward the pipe 1 at an angle of 45° are perforated and distributed in the circumferential direction (on the side opposite to the forward direction indicated by the arrow). It is set up. Further, a two-color thermometer (not shown) that can detect the temperature of the heating section of the tube 1 is integrally attached to the heating coil 13. When the temperature reaches the preset temperature,
A transmitting section (not shown) is provided for emitting a signal. 15 is a cooling water pipe that supplies cooling water 14 to the heating coil 13.

16 is a high frequency transmitter that generates a high frequency current;
Reference numeral 12 denotes a transformer that controls the magnitude of the high-frequency current supplied to the heating coil 13. This transformer 12 is turned on by a signal from the two-color thermometer (not shown), and is turned on by a limit switch 17 to be described later. It has a drive unit equipped with a relay switch (not shown) that is turned off by a signal from If this setting is made, when the relay switch is turned on, the heating coil 13 can be moved at the predetermined speed by moving forward in the direction of the arrow along the axial direction of the tube 1 while being guided by the support column 5b. .

11 is a control device, and this control device includes a relay switch (not shown) that is turned ON by a signal from the two-color thermometer (not shown) and turned OFF by a signal from a limit switch 17 (described later). figure)
and a spindle drive speed setting dial (not shown), and if the spindle drive speed setting dial is set to a predetermined speed in advance, when the relay switch is turned on, a predetermined number of speeds will be generated per unit time. It is capable of generating pulses. 10 is a stepping motor that rotates by a predetermined rotation angle per unit pulse generated by the control device 11; 9 is a stepping motor that rotates a predetermined amount of oil per unit pulse generated by the control device 11 due to the action of the stepping motor 10; Hydraulic pressure generating device 18b that sends from piping 18a to stepping cylinder 6 (details will be described later)
In this case, 6 is a hydraulic pipe that returns oil, and 6 is a hydraulic pipe that returns oil in proportion to the amount of oil per unit time that flows in from the hydraulic pipe 18a (in other words, the spindle drive speed setting dial is set to a predetermined speed. For example, since the amount of oil per unit time is constant, at a constant speed),
This is a stepping cylinder that can push out the spindle 7.

Reference numeral 17 denotes a limit switch which, when the heating coil 13 finishes heating up to the end of the thickened part, the transformer 12 comes into contact with it and closes, producing a signal.
The signal from the limit switch 17 is sent to the relay switch of the transformer 12, the high frequency oscillator 16, and the relay switch of the control device 11.
stops, and the high-frequency oscillator 16 stops generating high-frequency current.

Next, the operation of the pipe thickening processing apparatus configured as described above will be explained.

First, the spindle 7 of the stepping cylinder 6 and the transformer 12 are moved back. The tube 1 to be thickened is passed through the heating coil 13, and one end thereof is inserted into the positioning part 4a of the press bed 4.
The other end is fixed with a support jig 8 by moving the spindle 7 forward in the direction of the arrow. heating coil 13
The transformer 12 is advanced in the direction of the arrow until it reaches one end of the thickened portion of the tube 1.

A two-color thermometer (not shown) of the heating coil 13 is set to a predetermined temperature. With the heating coil movement speed setting dial (not shown) of the transformer 12,
The moving speed of the heating coil can also be adjusted using a spindle drive speed setting dial (not shown) of the control device 11.
Then, the driving speed of the spindle is set in advance (how to set the driving speed of the spindle depending on the thickness increase rate will be explained in a specific example to be described later).

Turn on the high frequency oscillator 16 and turn on the heating coil 1.
At the same time as starting the high-frequency induction heating of the tube 1 by the cooling water pipe 15, the cooling water 14 is supplied from the cooling water pipe 15 to the heating coil 13.

When the temperature of the heated part of the tube 1 heated by the heating coil 13 reaches the predetermined temperature, a signal is output from the transmitting part of the two-color thermometer (not shown), and this
The signal is received by a relay switch (not shown) of the control device 11 and a relay switch (not shown) of the drive section of the transformer 12. Then, the control device 11
The stepping motor 10 is turned on and generates a predetermined number of pulses per unit time in accordance with a preset spindle drive speed, and upon receiving the pulses, the stepping motor 10
The control device 11 rotates by a predetermined rotation angle per unit pulse generated, and the hydraulic pressure generating device 9 sends a predetermined amount of oil per unit pulse generated by the control device 11 from the hydraulic piping 18a to the stepping cylinder 6. The ping cylinder 6 is connected to the hydraulic pipe 18a
The oil flowing in from the tube pushes the spindle 7 at the preset constant driving speed, thereby compressing the tube 1 in the axial direction at a constant speed. Meanwhile, the relay switch of the transformer 12 is also turned on, and the transformer moves in the direction of the arrow at a preset moving speed, continuing to heat the tube 1 at the predetermined temperature. The amount of water injected from the injection port 13a of the heating coil 13 is adjusted to narrow the deformation area of the tube 1 so that the heating width at this time is about twice the plate thickness or less.

When the transformer 12 moves forward in the direction of the arrow and the heating coil 13 finishes heating the other end of the thickened part of the tube 1, the transformer 12 switches the limit switch 17.
, the transformer 12 and the stepping motor 10 stop, the high-frequency oscillator 16 stops generating high-frequency current, and the thickening of the tube 1 is completed.

Thereafter, after the tube 1 has cooled down, the supply of cooling water 14 is stopped, and the thickened tube 1 is taken out.

FIG. 3 is a perspective view showing an example of a pipe whose wall thickness has been increased by the pipe wall-thickening processing apparatus according to FIG. 2.

In FIG. 3, reference numeral 19 indicates a thickened portion of the pipe 1, and the thickened portion 19 has a uniform thickness increase rate and has no irregular deformation.

In this way, the heating coil 13 that moves along the axial direction of the tube 1 sequentially locally heats the thickened portion of the tube 1 while the spindle driven at a constant speed is applied to the tube 1. At step 7, by performing the swaging process by applying a compressive force, the thickness of the thickened portion of the pipe 1 can be uniformly thickened at a predetermined thickening rate.

Next, a specific example will be described.

Pipe 1 has an outer diameter of 216mmφ, a plate thickness of 8.6mm, and a length of 5.5mm.
Thickening rate of 500mm long carbon steel pipe
We will explain the case of increasing the thickness at 31%.

The conditions for high-frequency induction heating using the heating coil 13 are a frequency of 3000Hz, an output of 85Kw, and a heating temperature of 850℃.
and the moving speed of the heating coil 13 to be 1 mm/
It was set as min.

When setting the drive speed of the spindle 7,
A preliminary experiment as shown in FIG. 4 was conducted.

FIG. 4 is a spindle drive speed-thickness increase rate relationship diagram showing an example of the relationship between the spindle drive speed and the thickness increase rate when the moving speed of the heating coil is constant.

In this FIG. 4, 20 is the heating coil 13
It shows the relationship between the spindle drive speed and the thickness increase rate when the moving speed of is 1 mm/min.

As is clear from Figure 4, in order to increase the thickness by 31%, the driving speed of the spindle 7 must be increased by 0.3 mm/
It should be min.

When the above-mentioned conditions were set and the thickness increase processing of the carbon steel pipe was carried out using the thickness increase processing apparatus according to FIG. 2, the desired thickness increase rate of 31% was achieved.
We were able to perform thickening processing without irregular deformation.

According to the embodiment described above, there are the following effects.

(1) It is possible to provide a method and apparatus for increasing the thickness of a pipe, which can achieve uniform thickness increasing without irregular deformation.

(2) According to the pipe thickening processing method of this embodiment, the pipe 1
Since it is possible to increase the thickness uniformly at any location of the pipe, it is possible to perform secondary processing (for example, bending,
burring processing, tube expansion processing, etc.), if this secondary processing part is thickened beforehand,
The apparent decrease in plate thickness due to plastic deformation can be reduced. Therefore, there is no need to use thick-walled pipes, reducing material costs by 10-20%.

(3) According to the pipe thickening processing apparatus of this embodiment, the pipe 1
Since the spindle 7 is provided which can compress the tube 1 at a constant speed, there is no risk of irregular deformation of the tube 1 during the thickening process.

(4) Since tube 1 is compressed at a constant speed,
Even if the heating temperature fluctuates during the thickening process and the deformation resistance of the tube material changes, the desired thickening rate can be obtained regardless of the fluctuation.

(5) Since the desired thickness increase rate can be obtained by compressing the tube 1 at a constant speed, there is no need to strictly control the heating temperature of the tube 1, and the thickness increase process can be easily controlled.

In addition, in this embodiment, the heating coil 13
Furthermore, since the injection port 13a for injecting the cooling water 14 is provided, there is an advantage that the heating width can be controlled by adjusting the amount of water injected from this injection port.

Incidentally, even if the injection port is not provided, that is, even if no injection is made, there is little risk of irregular deformation of the tube 1 in practical terms.

As described above in detail, the present invention has the following effects.

○B Buckling the thickened part of the pipe at the desired thickening rate.
Thickness can be increased uniformly without irregular deformation such as wrinkles.

○B Since the tube is compressed at a constant speed, even if the heating temperature fluctuates during the thickening process and the deformation resistance of the tube material changes, the desired thickening rate can be achieved regardless of the fluctuations. It will be done.

C. Since the desired thickness increase rate can be obtained by compressing the tube at a constant speed, there is no need to strictly control the heating temperature of the tube, and the thickness increase process can be easily controlled.

○ D. It is possible to increase the thickness of any part of the pipe uniformly, so when performing secondary processing on the pipe, by increasing the thickness of this secondary processing section in advance, it is not necessary to use thick-walled pipes. , and material costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a pipe whose thickness has been increased by a conventional method for increasing its thickness, and FIG.
FIG. 3 is a partial cross-sectional view showing an example of a pipe wall-thickening processing device and a pipe to be wall-thickened by the device.
FIG. 2 is a perspective view showing an example of a pipe whose wall thickness has been increased by the pipe wall-thickening processing apparatus according to FIG. 2, and FIG. It is a spindle drive speed - thickness increase rate relationship diagram showing an example of the relationship with the rate. 1...Pipe, 6...Stepping cylinder, 7...
...Spindle, 10...Stepping motor, 1
DESCRIPTION OF SYMBOLS 1...Control device, 12...Transformer, 13...Heating coil, 13a...Injection port, 14...Cooling water.

Claims (1)

[Scope of Claims] 1. While heating the portion of the tube to be thickened sequentially and locally at a constant width using a heating coil, the tube is compressively deformed at a constant speed by controlling the load on a hydraulic servo cylinder such as a stepping cylinder. A compressive force is applied to the tube so that the swaging rate is defined by a combination of the spindle driving speed of the hydraulic servo cylinder and the moving speed of the heating coil, thereby controlling the deformation area of the tube by the heating coil. A method for increasing the thickness of a pipe, comprising increasing the thickness of the portion to be increased while moving at a constant speed. 2. A hydraulic servo cylinder such as a stepping cylinder capable of compressing the pipe in the axial direction at a constant speed using a spindle, and a hydraulic servo cylinder such as a stepping cylinder that is arranged around the outer circumference of the pipe and heats the pipe with a constant width. and an annular heating coil movable along the axial direction of the tube so that a deformed region of the tube moves at a constant speed. 3. The tube extension according to claim 2, characterized in that the heating coil is provided with an injection port for injecting part of the cooling water for cooling the heating coil toward the tube. Meat processing equipment.