JPH0154123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for processing the inner surface of a metal tube for forming unevenness or spiral grooves on the inner surface of the metal tube.

For example, metal tubes (copper tubes,
Some aluminum tubes (such as aluminum tubes) have irregularities or helical grooves formed not only on the outer surface but also on the inner surface in order to improve heat transfer.

Conventionally, when forming irregularities or spiral grooves on the inner surface of a metal tube, the metal tube is fed into the axial direction by drawing, for example, and the metal is inserted into the plug inserted from the outside into the metal tube. This was done by pressing a die, which is a member for external rolling, through a pipe. However, in this processing method, when the metal tube flows,
An extremely large frictional resistance force was generated between the metal tube and the die, and therefore, drawing had to be performed with a considerably strong force. Therefore, for example, when applying larger processing or increasing the processing speed, the metal tube must be pulled out with a correspondingly stronger force, but doing so may cause damage to the metal tube. Therefore, within a certain limit, it was not possible to add a larger amount of processing or increase the processing speed. Also,
Since the plug is supported on the outside of the metal tube via a mandrel, there is a drawback in that it is not possible to process a metal tube longer than a predetermined length.

This invention was made in view of the above circumstances,
It is an object of the present invention to provide an apparatus for processing the inner surface of a metal tube, which can increase the degree of machining without damaging the metal tube, increase productivity by increasing the machining speed, and can process even long products. This is the purpose.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. This device includes a metal tube drawing machine 2 that rolls a metal tube 1, and a metal tube drawing machine 2 that is placed downstream of the metal tube drawing machine 2, and that forms a predetermined shape on the inner surface of the metal tube 1 processed by the metal tube drawing machine 2. A metal pipe inner surface processing machine 3 for applying the metal pipe, and a metal pipe transfer mechanism (not shown) that is arranged after the metal pipe inner surface processing machine 3 and that transports the metal pipe 1 in its axial direction.
(corresponding to the conventional drawing).

First, the metal tube drawing machine 2 will be explained. 21
is a die, which is fixedly attached to a frame (not shown). The metal tube 1 is inserted through the center of the die 21 . In addition, a drawing plug 22 is provided at a position corresponding to the die 21 inside the metal tube 1.
are arranged in a floating manner.

Next, the metal tube inner surface processing machine 3 will be explained.

Reference numeral 31 denotes a hollow cylindrical rolling roll support, which is rotatably supported by a frame (not shown) and rotated in the direction of the arrow in FIG. 2 by a drive mechanism (not shown). ing. The metal tube 1 is disposed through the center of the roll support 31 . Further, on the inside of the rolling roll support 31 and on the outside of the metal tube 1, there is provided a metal tube 1 that is spaced apart from the inner circumferential surface of the rolling roll support 31 and inclined at a predetermined angle with respect to the axis of the metal tube 1. A plurality of, for example, three rolling rolls 32 that are pressed together are attached to an arm 33.
Each is rotatably supported via a shaft. On the other hand, inside the metal tube 1, at a position corresponding to the rolling roll 32, an inner surface processing plug 34 is floatingly arranged. This inner surface processing plug 34 is rotatably connected to the extraction plug 22 via a rod 35. Further, the outer surface of the inner surface processing plug 34 is formed in a predetermined shape, for example, a helical groove.

Next, a case will be described in which a metal tube is processed using the metal tube inner surface processing apparatus configured as described above. First, a pull-out plug 2 is inserted into a metal tube 1, which is a workpiece.
2, the inner surface machining plug 34, and the rod 35 connecting the two are inserted in a predetermined direction. Next, this metal tube 1 is arranged so as to pass through the processing hole 21a provided in the center of the die 21, and further to pass through the center of the rolling roll support 31.
Thereafter, one end of the metal tube 1 is held by a metal tube transfer mechanism (not shown). Next, the rolling roll support 31 is rotated, and a metal tube transfer mechanism (not shown) is driven, thereby transferring the metal tube 1 from the left to the right in FIG. Start processing.

When the metal tube 1 first passes through the metal tube drawing machine 2, it is rolled to a predetermined tube diameter and thickness by the die 21 and the drawing plug 22, and then when it passes through the metal tube inner surface processing machine 3, it is rolled to a predetermined tube diameter and thickness. , a helical groove is formed on the inner surface. By the way, when the metal tube inner surface processing machine 3 is in a driving state, the rolling roll support 31 is rotated by a drive mechanism (not shown), and as a result, each rolling roll 32 revolves around the metal tube 1. , and since it is strongly pressed against the outer surface of the metal tube 1, it rotates about its axis. Then, since each rolling roll 32 is inclined at a predetermined angle with respect to the axis of the metal tube 1, when the rolling roll 32 rotates in pressure contact with the metal tube 1, the axial component of the frictional force generated between the two rolls 32 becomes a thrust that moves the metal tube 1, and thereby the metal tube 1 receives a force in the direction of movement. At the same time, the rolling roll 32 is strongly pressed against the outer surface of the metal tube 1, so that the inner surface of the metal tube 1 is pressed against the inner surface machining plug 34 to form a helical groove. Also, at this time, the inner surface processing plug 34 receives a force in the direction in which the metal tube 1 is transferred due to the frictional force with the metal tube 1, but since it is connected to the extraction plug 22 via the rod 35, It is always accurately held in a position corresponding to the rolling roll 32.

As mentioned above, the rotation of the rolling roll 32 includes a component in the direction in which the metal tube 1 is transferred.
The frictional force that conventionally acted in the direction of preventing the transfer of the metal tube 1 now acts in the direction of positively transferring the metal tube 1, thereby increasing the processing speed of the metal tube 1. Wear. In addition, the rolling roll 3
The force that 2 applies to the metal tube 1 is divided into a pressing force that acts perpendicularly to the outer surface of the metal tube 1 to roll the metal tube 1, and a force that opposes the frictional force that occurs in a direction perpendicular to this pressing force. However, since the rolling rolls 32 are inclined with respect to the metal tube 1, the frictional force becomes extremely small, and therefore the force opposing this frictional force also becomes extremely small. As a result, the force applied by the rolling rolls 32 to the metal tube 1 is reduced compared to the conventional example, but the pressing force for rolling the metal tube 1 does not change, so the degree of processing of the metal tube 1 does not change.

Furthermore, since the frictional force becomes smaller, the tensile force applied to the metal tube 1 decreases, and even if the depth of the groove of the inner surface machining plug 34 is increased by that difference and the degree of machining of the metal tube 1 is increased, the metal tube 1 is It will not be damaged.

In addition, if it is desired to further increase the machining speed or increase the degree of machining, the sizes of the plug 22 and the die 21 should be adjusted within the range where the drawing plug 22 does not come out of the position corresponding to the die 21. Therefore, the frictional resistance force when the metal tube 1 is transferred may be made smaller. Also,
When the rolling roll 32 rotates while being in pressure contact with the metal tube 1, the metal tube 1 is subjected to a torsional force in the direction in which the rolling roll 32 rotates due to part of the frictional force generated between the two. Since the metal tube 1 is rolled in the machine 2 and is also prevented from rotating, twisting of the metal tube 1 does not occur.

Furthermore, the inner surface machining plug 34 receives a rotational force around its axis due to the frictional force with the metal tube 1, but since it is rotatable with respect to the rod 35, it rotates according to the rotational force. Therefore, the helical groove provided on the inner surface of the metal tube 1 is not deformed.

In addition, as a prior art, there is known an inner surface processing device for a metal tube in which a rolling roll is rolled on the inner circumferential surface of a rolling roll support and the driving force of the rolling roll support is transmitted to the rolling roll by frictional force. ing. In such a processing device, the frictional force between the inner circumferential surface of the rolling roll support and the rolling roll and the frictional force between the rolling roll and the metal tube are balanced, so that as the rolling roll revolves, , it rotates on its own axis, but if the fluctuation in the transfer speed of the metal tube exceeds the allowable range, an overload acts on the rolling roll, and the frictional force between the rolling roll and the inner circumferential surface of the rolling roll support, and the frictional force between the rolling roll and the rolling roll support are The balance with the frictional force of the metal tube is lost. If this balance is disrupted, problems such as the rolling rolls jostling the metal tube or even the rolling rolls locking the metal tube occur. At this time, the rolling rolls are simply driven by frictional force, so when the rolling rolls become locked, they slip and the rolling roll supports spin idly, resulting in the line being stopped and the rolling rolls being locked. There is a problem that recovery work such as releasing the status must be performed, resulting in a decrease in productivity.

However, as in the above embodiment, the rolling roll 32
If the roll support 31 is rotatably supported by the roll support 31 at a distance from the inner peripheral surface of the roll support 31, even if an overload is applied to the roll 32, the problem of jitter caused by the roll 32 will occur. but,
The rolling roll 32 is not locked. This is because the rolling rolls 32 are not driven by frictional force, but are forcibly rotated by the rolling roll support 31, so even if gagging occurs, the drive-blocking force caused by the gagging is greater than the drive-blocking force. By applying a driving force to the roll 32 from the roll support 31, the roll 32 can be caused to revolve. Therefore, in the case of the above embodiment, the machining process can be continued without stopping the line, and there is no need for recovery work such as unlocking as in the past.
As a result, it is possible not only to improve productivity, but also to advance unmanned production lines, and ultimately to reduce costs.

In addition, in the conventional technology described above, in order to transmit driving force through frictional force, the faster the roll support is rotated, the more the metal tube is plastically deformed due to the rotation of the roll support. As a result, slips occur between the inner circumferential surface of the roll support and the roll. In this case, the transmission efficiency of the driving force decreases by the amount of slip that occurs, and no matter how precisely the mill roll support is rotated at high speed, the mill roll cannot be rotated at high speed, and there is a limit to the speed increase. Furthermore, when slipping occurs, a large amount of frictional heat is generated due to friction between the inner circumferential surface of the roll support and the roll, which accelerates the deterioration of the roll support and the roll. It cannot be said that it is suitable for

On the other hand, in the above embodiment, unlike the prior art, the driving force of the roll support 31 is not transmitted to the roll 32 by frictional force, so that the inner circumferential surface of the roll support 31 is No slip occurs between the roll and the rolling roll 32. This means that there is no transmission loss of driving force due to slip. Therefore, even if the rotation speed of the roll support 31 is increased, the roll 32 can follow the rotation of the roll support 31, which is more suitable for increasing the speed. Furthermore,
In the above embodiment, since no frictional heat is generated between the roll support 31 and the roll 32, it can be said that it is suitable for increasing the speed, and also extends the life of the roll support 31 and the roll 32. be able to.

In addition, although the rolling roll 32 is made into a simple cylindrical shape in the above embodiment, it is not limited to this.
For example, it may be made into a string shape. In this way, the area in contact with the metal tube 1 becomes larger, and good rolling can be performed.

Further, in the above embodiment, the rolling roll 32 is only rotatably supported, but if the rolling roll 32 is forcibly rotated using a drive source, for example, the rolling roll 32 relative to the metal tube 1 can be rotated.
The rotation speed of the machine can be increased, and therefore the processing speed can be further increased.

As explained above, according to the apparatus for processing the inner surface of a metal tube according to the present invention, the rolling roll is arranged at an angle with respect to the axis of the metal tube, and the plug for inner surface processing is supported inside the metal tube. Because of this, the rotation of the rolling rolls includes a component in the direction in which the metal tube is transferred, which makes it possible to reduce the frictional force between the metal tube and the rolling rolls, thereby increasing the degree of processing. It has the advantage of increasing productivity by increasing processing speed, and also allows processing of long products.

In addition, since the rolls are supported by the roll support at a distance from the inner peripheral surface of the roll support, and are forcibly driven by the roll support, fluctuations occur in the transfer speed of the metal tube. Even if an overload is applied to the rolling rolls, the rolling rolls can continue to revolve without becoming locked, so there is no need to perform recovery work such as stopping the line and releasing the locking state. Not only can productivity be improved, but costs can also be reduced.

Furthermore, there is no transmission loss of driving force due to slip between the inner circumferential surface of the roll support and the roll, and no frictional heat is generated between them, making it suitable for increasing processing speeds. but also
It is possible to extend the life of the mill roll and the mill roll support.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal sectional front view showing an embodiment of the apparatus for processing the inner surface of a metal tube according to the present invention, and FIG.
FIG. 2 is a schematic vertical sectional side view taken along the - line in the figure. DESCRIPTION OF SYMBOLS 1...Metal tube, 2...Metal tube drawing machine, 3...Metal tube inner surface processing machine, 21...Dice, 22...Plug for drawing, 31...Roll roll support, 32...
Rolling roll, 34...Plug for inner surface processing, 35...
...Rotsud.

Claims (1)

[Claims] 1 A metal pipe drawing machine 2 for drawing out the metal pipe 1, and a metal pipe drawing machine 2 disposed after the metal pipe drawing machine 2.
a metal tube inner surface processing machine 3 that gives a predetermined shape to the inner surface of the metal tube 1 processed by the metal tube 1; The metal tube drawing machine 2 includes a die 21 that presses against the outer surface of the metal tube 1, and a metal tube transfer mechanism for transferring the metal tube 1 in
The metal tube inner surface processing machine 3 includes a drawing plug 22 floating at a position corresponding to the die 21 inside the metal tube inner surface processing machine 3, and the metal tube inner surface processing machine 3 is a hollow rolling mill that is rotatably supported and has the metal tube 1 inserted therethrough. A roll support 31 and a metal tube 1 rotatably supported within the roll support 31 at a distance from the inner peripheral surface of the roll support 31 .
a plurality of rolling rolls 32 arranged at an inclination angle with respect to the axis of the metal tube 1 and press-contacting the outer periphery of the metal tube 1;
The plurality of rolling rolls 32 inside the metal tube 1
Plug 3 for inner surface processing is floated at a position corresponding to
4, wherein the drawing plug 22 and the inner surface processing plug 34 are rotatably connected by a rod 35.