JP3438533B2 - Manufacturing method of inner grooved pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an inner grooved tube, and more particularly to a method for manufacturing an inner grooved tube using a metal tube drawing method.

[0002]

2. Description of the Related Art One of the methods for manufacturing an inner grooved tube is a drawing method.

In this drawing method, as shown in FIG. 9, a grooved plug 4 having a groove on its outer peripheral surface, which is connected to a floating plug 2 through a connecting rod 3, is arranged in a metal tube 1, and from one side. The floating plug 2 is fixed to the drawing die 9 by passing the metal tube 1 through the drawing die 9, and the metal is passed through the pressing means 101 such as a plurality of rolls or balls which are respectively planet-rotated at a certain position of the grooved plug 4. By squeezing the tube 1 onto the grooved plug 4 and pulling the metal tube 1 from the other side to pull it out of the grooved plug 4, the inner surface of the metal tube 1 is continuously grooved.

In the conventional method shown in FIG. 9, a driving portion 6 for pushing the metal tube 1 into the drawing die 9 is provided on the entry side of the drawing tube 9 for holding the floating plug 2 into the metal tube 1. Further, a finishing die 5 for finishing to a predetermined outer diameter is provided on the exit side of the metal pipe 1 of the pressing means 101, and the metal pipe 1 having a groove 7 formed on the inner surface thereof passes through the finishing die 5 to obtain a predetermined outer diameter. It becomes the tube 8 with an inner groove having a diameter.

More specifically, the metal tube 1 is moved by pushing the drawing die 9 by the driving portion 6 on the entry side of the metal tube 1 and withdrawing the inner grooved tube 8 on the exit side of the finishing die 5.
The drive unit 60 on the entry side of the metal tube 1 of the drawing die 9 reduces the drawing force of the inner grooved tube 8 on the exit side of the finishing die 5.

As another conventional method for reducing the pulling force, a caterpillar 70 or the like is provided between the pulling die 9 and the pressing means 101 as shown in FIG. There is a method of reducing the pulling force on the exit side of the finishing die 5 by pulling out the metal tube 1.

[0007]

However, in the method of pushing the metal tube 1 into the drawing die 9 for locking the floating plug 2 by the driving unit 60 as in the prior art of FIG. 9, the driving unit 60 and the drawing die 9 are used. When an annealing material is used as the material of the metal tube 1, a buckling occurs in the metal tube 1 between the feeding device section (driving section 60) and the drawing die 9, and the inner surface There was a drawback that it hindered the grooved pipe processing.

In the case of the method of driving the caterpillar 70 or the like between the drawing die 9 and the pressing means 101 to pull the metal tube 1 as in the prior art shown in FIG. 10, the drawing and pressing means from the drawing die 9 are used. Since the pushing into 101 is performed at the same time, it is difficult to set the moving speed of the caterpillar 70 and the pressing force against the metal tube 1. Depending on the moving speed of the caterpillar 70 and the moving speed of the metal tube, the caterpillar portion 70 acts as a load. However, there is a drawback that the drawing force at the final portion of the inner surface grooved pipe processing increases, and the inner surface grooved metal pipe 8 may be disconnected.

Therefore, an object of the present invention is to solve the problems of the prior art and to reduce the drawing force applied to the metal pipe at the final stage of the inner surface grooved pipe processing, thereby improving the processing speed of the inner surface grooved pipe. It is to provide a manufacturing method.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 draws out a metal pipe through a gap between a drawing die and a floating plug, and then connects the floating plug with a connecting rod. Manufacture of an inner grooved pipe in which a grooved plug having a groove formed on the outer peripheral surface thereof is passed through the metal pipe and is pulled out while pressing the metal pipe onto the grooved plug by pressing means to form a groove in the metal pipe. In the method, the metal tube passed through the drawing die is sandwiched between a pair of grooved belts of an auxiliary drawing device , and the belts are transferred.
It is a method to pull out while moving and pulling ,
The groove of the blade is arcuate, and the radius of the arc is the above-mentioned radius.
Formed within 85% of the radius of the metal pipe sandwiched between
It is a method.

According to a second aspect of the invention, the auxiliary drawing apparatus is controlled so as to pull the metal tube at a speed which is 1.5 times or more the moving speed of the metal tube through the drawing die. Is.

According to a third aspect of the present invention, the belt has a timing.
It is a method consisting of Govert .

[0013]

[0014]

[0015]

The gist of the present invention is to provide an auxiliary drawing device for drawing a metal tube between a drawing die for holding a floating plug and a pressing means for pressing the metal tube against the grooved plug to form a groove on the inner surface of the metal tube. Auxiliary drawing device metal tube
The radius of curvature of the part of the belt that contacts
% Of the arc-shaped groove and the auxiliary drawing device
The speed of the withdrawal part should be more than 1.5 times the moving speed of the metal pipe.
Lies in the fact was.

According to the above construction, the metal pipe is pulled by the auxiliary drawing device at a speed higher than the moving speed of the metal pipe while being in close contact with the arcuate groove of the auxiliary drawing device. As a result, the pulling force of the entire body is reduced, and it becomes difficult for the inner grooved tube to be disconnected.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view of an inner grooved tube manufacturing apparatus according to the present invention.

As shown in FIG. 1, the inner grooved tube manufacturing apparatus 3
00 is a floating plug 2 inserted into the metal tube 1, a drawing die 9 that engages with the floating plug 2 and reduces the diameter of the metal tube 1 around it, and is connected to the floating plug 2 via a connecting rod 3. And a grooved plug 4 having a groove formed on the outer periphery thereof, and a plurality of rolls, balls, etc., each of which planetarily rotates to press the metal tube 1a drawn from the drawing die 9 from the outside to the outer circumference of the grooved plug 4. The pressing means 101, a finishing die 5 for reducing the pressed metal tube 1b to a desired outer diameter, and an auxiliary drawing device 301 provided between the drawing die 9 and the pressing means 101.

These drawing dies 9 and auxiliary drawing device 3
01, the pressing means 101, and the finishing die 5 are sequentially arranged along the passage of the metal tube 1.

FIG. 2 shows an enlarged view of the auxiliary drawing device 301.

As shown in FIG. 2, the auxiliary drawing device 301
Is a measuring unit 18 for measuring the moving speed Vc of the metal tube 1a.
And a device section 1 for pulling by sandwiching the metal tube 1a from both upper and lower sides.
9, and the device unit 19 draws the metal tube 1a from the drawing die 9 at a predetermined speed according to the measurement value from the measuring unit 18.

The device section 19 is mainly composed of a pair of belt mechanisms 30 and 31 provided on both upper and lower sides of the metal tube 1a. Since the belt mechanisms 30 and 31 have the same configuration, only the upper belt mechanism 30 will be described.

The belt mechanism 30 includes pulleys 11 and 1 in which the belt 10 which is brought into contact with the metal tube 1a is arranged in a triangular shape.
It is designed to be moved by the rotation of the pulleys 11, 11, 12 while the belt 10 is held by a holding plate 15 provided between the two pulleys 11, 12 that are supported by the pulleys 1, 12 and pressed against the metal pipe 1a. , Pulley 11,1
1, 12 and the pressing plate 15 are mounted on the mounting plate 13.

One of these three pulleys 11, 11 and 12 is connected to a drive system, which will be described later, as a drive pulley 12.

In the upper belt mechanism 30, the mounting plate 13 is
It has a mechanism of sliding with respect to a fixed support stand 17, and a rolling-down device 16 is attached in order to move these mounting plates 13 toward the metal tube 1a and press the belt 10. Although not shown, the belt 10 has grooves formed on its surface so that a large frictional force is generated when the belt 10 comes into contact with the metal tube 1a.

FIG. 3 shows a cross-sectional view of the belt 10.

As shown in FIG. 3, the belt 10 is formed in a loop shape, and a contact portion 10o for sticking urethane rubber to the outer peripheral surface for contacting with a metal pipe is provided on the outer peripheral surface, and a meshing portion with a pulley for the inner peripheral surface. 10i is formed and serves as a timing belt.

The contact portion 10o has a regular trapezoidal cross section, and an arcuate groove 202 is formed at the center of the upper base (contact surface) of the trapezoid according to the cross sectional shape of the metal tube.
Further, the upper base (contact surface) of the trapezoid is formed at a height that is set back from the center of the circle of the arcuate groove 202 by a distance d.

The radius of curvature Rb of the arcuate groove 202 is 0.85 (85%) or less with respect to the radius Rc of the outer circumference of the metal tube 1a after passing through the drawing die 9 shown in FIG. ing.

The belt 10 is rotated at the moving speed Vb, which is controlled in accordance with a signal from the measuring unit 18 which measures the moving speed Vc of the metal tube.

FIG. 4 shows a speed control block diagram of the measuring unit 18.

As shown in FIG. 4, the measuring unit detects the moving speed of the metal pipe drawn from the drawing die and outputs a signal to the control unit 33, which will be described later, and the metal pipe speed detecting unit 31.
A speed setting unit 32 for setting the moving speed of the belt from the moving speed of the metal tube; a control unit 33 for outputting a signal to a belt driving unit 34 described later so that the moving speed of the belt becomes the set speed; A belt drive unit 34 that drives the belt in response to a signal from 33 and a belt speed detection unit 35 that detects the speed of the driven belt and outputs the detected speed to the control unit 33.

The speed setting unit 32 determines the moving speed Vc of the metal tube.
The ratio Vb / Vc of the moving speed Vb of the belt with respect to is set.

The control unit 33, based on the moving speed signal of the metal pipe from the metal pipe speed detecting unit 31 and the signal from the belt speed detecting unit 35, sets the speed ratio Vb /
A control signal is given to the belt drive unit 34 so that it becomes Vc.

The belt driving section 34 is connected to the driving pulley 12 shown in FIG. 2, and rotates the driving pulley 12 in response to a control signal to move the belt 10 at a set speed. .

To control the speed of the belt, the control unit 33 outputs a control signal to the belt driving unit 34 based on the signal from the speed setting unit 32, the signal from the metal pipe speed detecting unit 31, and the signal from the belt speed detecting unit 35. It is supposed to be done by.

Next, a method of manufacturing the inner grooved tube according to the present invention will be described.

When the inner grooved pipe manufacturing apparatus 300 is used to manufacture the inner grooved pipe 80, the floating plug 2 and the grooved plug 4 are arranged in the metal pipe 1, and the metal pipe 1 is drawn from one side. Pass through 9. The metal tube 1a is pulled out from the drawing die 9, and the pressure reducing device 16 is operated to move the pulleys 11 and 12, the belt 10 and the mounting plate 13 to which the pressing plate 15 is attached, and the upper and lower belt mechanisms 30 and 31 are used. The metal tube 1a is sandwiched.

Simultaneously with the start of the drawing operation of the inner grooved tube 80 on the exit side of the finishing die 5, the driving pulley 12 of the auxiliary drawing device 301 is driven. As a result, the belt 10 moves at the rotation speed Vb.

As the belt 10 moves, the metal tube 1a
Due to the frictional force between the belt 10 and the belt 10, the metal pipe 1a is subjected to the action of being pulled out from the drawing die 9 by the auxiliary drawing device 301.

The contact portion 10o of the belt 10 is a metal tube 1a.
Since it is formed in an arc shape according to the outer diameter of
A large frictional force is generated in close contact with a. As a result, the metal pipe 1a can be pulled with a larger force, and the pulling force Fz is reduced.

This withdrawal is carried out with the floating plug 2 held in the withdrawing die 9, and the metal pipe 1a is successively grooved from the metal pipe 1a passing therethrough by the pressing means 101 at a certain position of the grooved plug 4. It is pressed onto the plug 4.

By this compression, the groove 7 is formed on the inner surface of the metal tube 1a, and the metal tube 1a is further pulled from the other side, whereby the groove 7 is sequentially formed on the inner surface of the metal tube 1a.

Finally, the finishing die 5 is passed through to reduce the inner grooved pipe 1b to a predetermined outer diameter.
The inner grooved tube 80 is produced.

As described above, according to the present invention, the pull-out force Fz of the inner grooved pipe 80 can be reduced, so that the inner grooved pipe 80 is less likely to be disconnected. Further, since the frictional force between the belt 10 and the metal pipe 1a is large, the pulling force Fz can be easily controlled, and the pulling speed can be adjusted so that the metal pipe having a deep inner groove or the twist angle of the groove with respect to the pipe axis can be controlled. Large metal tube,
Alternatively, it becomes possible to manufacture a metal tube or the like having grooves of different types.

Next, a modification of the present invention will be described.

FIG. 5 shows a modified example of the belt 10.

As shown in FIG. 5, the belt 20 of this modified example.
In No. 0, many small slits 203 are cut in the cross-sectional direction along the longitudinal direction of the belt 200. This allows
The discontinuity of the oil film on the surface of the metal tube can be improved and the frictional force can be increased.

FIG. 6 shows a modified example of the auxiliary drawing device 301.

As shown in FIG. 6, in the auxiliary drawing device 400 of this modification, a cleaning device for removing the oil film on the surface of the metal pipe on the entry side of the auxiliary drawing device 400 (between the drawing die 9 and the measuring portion 18). 20 is provided.

A cleaning liquid 21 is contained in the cleaning device 20, and the cleaning liquid 21 removes the lubricating oil used in the drawing die 9 attached to the surface of the metal tube. With this configuration, in the auxiliary drawing device 400, the frictional force between the belt 10 and the metal tube 1a becomes large, and the drawing force Fz of the metal tube 1a can be reduced.

Although only the upper mounting plate 13 is movable in the present embodiment, the lower mounting plate 13 may be movable in the same manner as the upper mounting plate 13.

[0055]

EXAMPLES Next, more specific examples of the present invention will be shown.
An experiment was conducted on the relationship between the drawing speed and the drawing force of a metal tube using the example.

In this experiment, as the metal tube, 12.7 mmφ
A copper pipe after annealing was used, a timing belt having urethane rubber attached was used as the belt, the radius Rc of the groove of the belt was 4.2 mm, and the drawing die had a diameter of 1 mm.
1.00 mmφ was used.

In the experiment for obtaining the relationship between the drawing speed and the drawing force of the metal tube, the metal tube is drawn through a drawing die, a moving speed measuring unit of the metal tube, and an auxiliary drawing device, and the metal tube at the time of drawing is drawn. The force Fz and the load Fb applied to the drawing die were measured by a load cell.

Further, the moving speed Vc of the metal tube after the metal tube passed through the drawing die from the measuring section and the moving speed Vb of the belt of the auxiliary drawing device were also measured.

FIG. 7 shows the result of the experiment as a speed ratio Vb /
The figure showing the change of load ratio Fz / Fb with respect to Vc is shown.

As shown in FIG. 7, the speed ratio Vb / Vc is 1
With the above, the load ratio Fz / Fb is 1 or less. This indicates that the auxiliary pulling device has a function of pulling out the metal pipe, and therefore the pulling force Fz of the metal pipe is reduced.

On the other hand, when the speed ratio Vb / Vc is 1 or less, the load ratio Fz / Fb becomes 1 or more, and the auxiliary drawing device acts as a load for drawing the metal pipe, so that the drawing force Fz of the metal pipe is increased. Indicates that.

From the above results, in order to reduce the drawing force Fz by the auxiliary drawing device, the belt speed Vb of the auxiliary drawing device is set to 1 of the metal pipe speed Vc after passing through the drawing die.
It turns out that you have to double or more.

Further, when the speed ratio Vb / Vc is up to 1.5,
The load ratio Fz / Fb linearly changes (decreases) with respect to the speed ratio Vb / Vc. From this, the speed ratio Vb / Vc
To reduce the change in load with respect to fluctuations in
It is desirable that / Vc be 1.5 or more.

Next, the speed ratio Vb / Vc is determined by the experimental method shown in FIG.
Was 1.5 times, and the change of the load ratio Fz / Fb to the ratio Rb / Rc of the radius of curvature Rb of the arcuate groove of the belt of the auxiliary drawing device and the radius Rc of the metal tube was measured.

In this experiment, the radius of the belt groove was 4.2 m.
The mR was kept constant, the copper tube after annealing was used as the metal tube, and the inner diameter of the drawing die was changed.

FIG. 8 shows the experimental result.

When the radius ratio Rb / Rc is 0.85 (85%) or more, the load ratio Fz / Fb rapidly increases. As a result, the radius of curvature Rb of the arcuate groove of the belt of the auxiliary drawing device is less than the radius Rc of the metal tube after passing through the drawing die.
It can be said that when the content is 85 (85%) or less, the effect of reducing the drawing force Fz of the metal tube by the auxiliary drawing device becomes large.

[0068]

In summary, according to the present invention, since the pulling force of the inner grooved tube finished to a predetermined diameter can be reduced, disconnection is less likely to occur.

Further, since the drawing force can be reduced, the drawing speed can be adjusted to adjust the drawing speed to a metal pipe having a deep groove on the inner surface, a metal pipe having a large twist angle with respect to the pipe axis, or a metal pipe having different kinds of grooves. Can be manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view of an inner grooved tube manufacturing apparatus showing an embodiment of the present invention.

FIG. 2 is an enlarged view of an auxiliary drawing device portion of FIG.

3 is a cross-sectional view of the belt portion of FIG.

4 is a block diagram showing belt speed control by the speed measuring unit in FIG. 1. FIG.

5 is a perspective view showing a modified example of the belt of FIG.

FIG. 6 is a cross-sectional view showing a modified example of the auxiliary drawing device of FIG.

FIG. 7 is a diagram showing an experimental result for confirming a pulling force reducing effect.

FIG. 8 is a diagram showing an experimental result for confirming a pulling force reducing effect.

FIG. 9 is a cross-sectional view showing a conventional inner surface grooved tube manufacturing apparatus.

FIG. 10 is a cross-sectional view showing a conventional inner surface grooved tube manufacturing apparatus.

[Explanation of symbols]

1 metal tube 2 Floating plug 3 connecting rod 4 Groove plug 5 finishing dies 9 Drawing dies 10 belts 11 pulley 12 Drive pulley 15 Presser plate 80 Inner Grooved Tube 101 pressing means 300 Inner Grooved Pipe Manufacturing Equipment 301 Auxiliary drawing device

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-7-24521 (JP, A) JP-A-9-57328 (JP, A) JP-A-60-15015 (JP, A) JP-A-60- 33814 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21C 1/00-19/00 B21C 37/00-43/04

Claims (3)

(57) [Claims] 1. A grooved plug, which is connected to the floating plug via a connecting rod and has a groove on its outer peripheral surface, is drawn into the metal pipe after the metal pipe is drawn out through a gap between the drawing die and the floating plug. A method for manufacturing an inner grooved pipe in which a metal pipe is passed through and pressed by a pressing means while pressing the metal pipe onto a grooved plug to form a groove on the inner surface of the metal pipe.
Sandwiched between the pair of grooved belts, a method of pulling pulling <br/> to move them belt groove of the belt
Has an arc shape, and the radius of the arc is
A method for manufacturing an inner grooved pipe, characterized in that the pipe is formed so as to have a radius of 85% or less of a sandwiched metal pipe . 2. The manufacturing of an inner grooved pipe according to claim 1, wherein the auxiliary drawing device is controlled so as to pull the metal pipe at a speed of 1.5 times or more the moving speed of the metal pipe through the drawing die. Method. 3. The method for manufacturing an inner grooved tube according to claim 1, wherein the belt is a timing belt .