JPH07290118A - Plug for manufacturing seamless pipe, device for attaching/detaching its plug bar and its automatic exchanging device - Google Patents

Abstract

PURPOSE:To carry out a plug changing operation easily and in a short time, with respect to a plug for manufacturing a seamless pipe, by providing a hollow part with a female screw in the opening side and making the inner part a cavity with its bore larger than the valley of the female screw and its length longer than that of the female screw. CONSTITUTION:The appearance of a plug is a cannonball shape, and the inside is hollow 6. The opening of the hollow part 6 is connected with a plug bar, and a female screw 4 is provided to be used at the time of separation. The inner part of the hollow part is a cavity whose bore is larger than the valley of the female screw 4 and whose length is longer than that of the female screw. The number of screw threads of the female screw 4 is somewhat smaller than the ordinary engaging example of a screw, and the pitch is on the large side so as to prevent the screw from falling while in use. Consequently, the plug is easily attached/detached from the device for attaching/detaching the plug.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling tool used for manufacturing a seamless steel pipe, more specifically, a plug, an attaching / detaching device for connecting / disconnecting it to / from a plug bar, and an automatic device for easily performing the attaching / detaching. Involved in the plug changer.

[0002]

2. Description of the Related Art Generally, in the production of seamless steel pipe,
Piercing mill that perforates a round steel piece to make a hollow shell, rolls the hollow shell manufactured by the piercing mill, reduces the wall thickness of the mill, and mills the shell mill rolled by the plug mill to reduce the wall thickness. Plugs and plug bars are used as rolling tools in a uniform reeler mill. At that time, since the plug is cooled after each rolling process, it is necessary to separate it from the plug bar connected to it, remove it, or replace it due to occurrence of cracks and wear due to long-term use. Therefore, the plug bar is usually equipped with an attachment / detachment device that enables connection and disconnection with the plug. The attachment / detachment device allows easy attachment / detachment of the plug, the plug being rolled freely rotates around the axis of the plug bar, and is always centered. It has excellent durability and is inexpensive. In need of functionality.

Therefore, various attachment / detachment devices have been conventionally developed. For example, as shown in FIG. 7, the attaching / detaching device disclosed in JP-A-58-202909 discloses a plunger 20.
It is characterized in that a rod-shaped jig (not shown) is pushed into the small hole 24 of the push-in stopper pin 21 to manually move back and forth. That is, a coil spring 22 that repels each other is incorporated between the push stopper pin 21 and the plunger 20, and the push stopper pin 21 is pushed by the rod jig against the force of the coil spring 22 and slid forward, A part of a steel ball 23, which is a locking member arranged at the tip of the plunger 20, is bitten into the plug 1 to connect with the plug 1. On the other hand, the detachment of the plug 1 from the plunger 20 is performed by sliding the plug 1 backward,
3 may be dropped into the space 6 at the tip of the plunger 20.

However, as represented by the above-mentioned technology, the conventional plug attaching / detaching device is complicated in mechanical structure, the locking portion using the steel ball is easily damaged, and the plug is dropped during rolling. There are many problems such as misrolling. Further, this attachment / detachment device is expensive and requires a large amount of cost for repair. Further, when it is attempted to automatically replace the plug 1 by using a robot or the like, it is necessary to quickly and accurately search for the small insertion hole 24 of the rod-like jig with a sensor, but unlike visual inspection, it takes time to search for it. In addition, there is a possibility that it will be mistaken for another flaw, and the reliability of the search remains questionable.

[0005]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention has a structure in which the plug replacement work currently performed manually in the manufacture of seamless steel pipes can be carried out more easily and in a shorter time, and has a long service life. It is also an object of the present invention to provide a plug and an attaching / detaching device for the plug bar, and an automatic plug exchanging device for attaching / detaching the plug and the plug bar.

[0006]

In order to achieve the above object, the inventor diligently reviewed the problems of the conventional plug attaching / detaching device, and if the connecting and disconnecting of the plug and the attaching / detaching device were carried out with a simple screw, it could be done manually. Alternatively, it was noticed that the robot could easily perform the desorption. The present invention embodies this focus, and is used for punching and rolling a round steel piece, and in a shell-shaped seamless steel pipe manufacturing plug having a hollow rear end, the hollow portion has an opening. On the side, a female screw to be screwed with the male screw at the tip of the rod-shaped member of the plug attaching / detaching device is provided, and at the back, a cavity having an inner diameter larger than the diameter of the valley of the female screw and a length longer than the female screw length is provided. It is a featured plug for manufacturing seamless steel pipes. Further, the present invention is preferably the plug for producing a seamless steel pipe according to claim 1, wherein the plug simultaneously satisfies the following conditions.

L ₁ ≧ (1/2) × L ₂ , φD ₁ ≧ (2
/ 3) × φD ₂ , 0.5 mm ≤ Δd ≤ 1.0 mm where L _{1 is the} length of the male screw at the tip of the rod member of the plug attaching / detaching device L ₂ : The total length of the plug φD ₁ : The inner diameter of the plug hollow φD ₂ : Rod-shaped member outer diameter of the plug attaching / detaching device Δd: Gap between the screw part and the straight part when the plug is attached And, with regard to the attaching / detaching device, the present invention is used when punching and rolling a round steel piece, and a rear end. A rod-shaped attachment / detachment device used for connecting and disconnecting a hollow shell-shaped seamless steel pipe manufacturing plug and a plug bar supporting the plug,
The tip part is a male screw whose first half is screwed with the plug,
The latter half is a cylindrical shape having an outer diameter smaller than the thread diameter of the female screw and a length longer than the female screw length, and a screw for connecting and disconnecting with the plug bar is provided at the rear end portion. It is a device for attaching and detaching a plug of a plug characterized by:
With respect to the attachment / detachment described above, the present invention includes a robot hand that holds the plug, a motor that rotates the robot hand around the plug axis, and a slider that moves the robot hand to the plug position. It is a featured automatic plug changer.

[0008]

According to the present invention, in a shell-shaped seamless steel pipe manufacturing plug having a hollow rear end, which is used for punching and rolling a round steel piece, the hollow portion has a plug attaching / detaching device on its opening side. Provide a female screw to be screwed with the male screw at the tip of the rod-shaped member,
Since the inner diameter is larger than the diameter of the root of the female screw and the length is a cavity longer than the female screw length, the structure of the plug and its attaching / detaching device is simple, and the small hole as in the past is used. No need to search for. As a result, the plug replacement work can be easily performed in a short time even if it is manually performed.
Further, in the present invention, the above-mentioned effect can be further promoted by using the plug for producing a seamless steel pipe according to claim 1, wherein the plug simultaneously satisfies the following conditions.

L ₁ ≧ (1/2) × L ₂ , φD ₁ ≧ (2
/ 3) × φD ₂ 0.5 mm ≦ Δd ≦ 1.0 mm where, L _{1 is the} length of the male screw at the tip of the rod member of the plug attaching / detaching device L ₂ : The total length of the plug φD ₁ : The inner diameter of the hollow part of the plug φD ₂ : Rod-shaped member outer diameter of the plug attaching / detaching device Δd: Gap between the screw part and the straight part when the plug is attached And, with regard to the attaching / detaching device, according to the present invention, the round end is used for punching and rolling, and the rear end is A rod-shaped attaching / detaching device used for connecting and disconnecting a hollow shell-shaped seamless steel pipe manufacturing plug and a plug bar supporting the plug, the front half of which is screwed with the plug. A male screw having a cylindrical shape whose outer diameter is smaller than the diameter of the crest of the female screw and whose length is longer than the female screw length in the latter half, and is connected to and separated from the plug bar at the rear end. The invention of the above-mentioned plug is effective by providing a screw. It was.

Further, according to the present invention, the plug replacement work is
To use an automatic plug changing device comprising a robot hand for gripping a plug, a motor for rotating the robot hand around a plug axis, and a slider for moving the robot hand to a plug position. As a result, it has become possible to mechanize the plug replacement work that has never been carried out.

In the following, the contents of the present invention will be specifically described with reference to FIGS.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, FIG. 1 shows a vertical sectional view of a plug 1 (outer diameter 146 mmφ) according to the present invention. In this embodiment, since it is made of 3.0% Cr-1.0% Ni low alloy steel, and it is not easy to machine the screw 4 part, a core having a screw shape is used from the casting stage. And cast. As for the shape, the external appearance is a bullet-like shape and the inside is hollow 6 as usual. However, the opening of the hollow 6 is provided with a female screw 4 which is used for connecting and disconnecting the plug bar. Further, the inner part of the hollow portion is a cavity having an inner diameter larger than the diameter of the valley of the female screw and a long length. The female screw 4
Is not directly screwed to the plug bar 12, but is used via the attachment / detachment device 2 to / from the plug bar 12 according to the present invention described later.

The characteristic feature of the female screw 4 is that the number of threads is less than that of a normal screw locking example (two threads in FIG. 1) in consideration of the ease of attachment and detachment. The pitch is large (long). As a result, the plug 1 can be easily attached to and detached from the plug attaching / detaching device 2, and the screw thread is only halfway up to the male screw 5 at the tip of the plug attaching / detaching device 2 as shown in FIG. After connecting the two, the plug 1 can freely rotate about the axis even during rolling. That is, the plug according to the present invention and the plug attaching / detaching device are not screwed together in a fixed state during rolling, but the threaded portions are allowed to pass through each other and are joined at a portion where no screw is present.

Next, FIG. 2 is a vertical cross-sectional view showing an attaching / detaching device 2 of the plug 1 and the plug bar 12 according to the present invention, and FIG. 3 is an assembly view of the attaching / detaching device 2 inserted in the plug 1. The attaching / detaching device 2 has a front end portion 3 and a rear end portion 8 which are formed of a round bar-shaped member whose center is thinner than the center, and a female screw 5 for connecting with the female screw 4 of the plug 1 is provided in the front half of the tip portion 3. The second half is simply elongated cylinder. The length of this column is also important,
It is longer than the length of the female screw of the plug 1. A screw 9 for connecting and disconnecting with the plug bar is provided at the rear end portion 8. Since the male screw 5 part of the attaching / detaching device 2 is easily worn during use, SC is used as a preventive measure.
It was manufactured by induction hardening using M440H and then cutting it out with a rotary lathe.

Regarding the size of the female screw 4 of the plug 1, in order to prevent the plug from hanging down and rubbing the male screw 5 during use, L ₁ ≧ (1/2) × L ₂ , φD ₁ ≧ (2/3) ) × φD
It is preferable to simultaneously satisfy the three equations of ₂ , 0.5 mm ≤ Δd ≤ 1.0 mm. Further, as shown in FIG. 4, in order to secure the centering of the plug 1 during use, the angle (α) formed by the mating surface between the plug 1 and the attachment / detachment device 2 is α ≧ 15 °. In addition, male screw and female screw 4
The orientation of the plug 1 and plug bar 1 at the end of drilling the material
In consideration of the rotational speed difference of 2, the value is determined to be left or right.

FIG. 5 shows a state in which the plug 1 is separated from the attaching / detaching device 2 in the automatic plug exchanging device according to the present invention, and FIG. 6 shows an on-site arrangement (plan view) of the automatic plug exchanging device. This is an example. As shown in FIG. 5, in the automatic plug changing device, since the plug 1 and the attaching / detaching device 2 according to the present invention are of a screw type, it is only necessary to hold and rotate. Therefore, the known positioning slider 11, the rotation motor 25 of the robot hand 10, the robot hand 1
It was produced by combining 0 and. As is apparent from FIG. 6, the supply of the new plug 1 and the disposal of the used plug 1 can be automatically performed by the robot hand 10 directly from the supply pallet 15 or directly to the waste pallet 16. It should be noted that, in use, in order to position the plug bar 12, it is necessary to arrange the bar aligning device 17 and the plug bar 12 core aligning device.

Finally, the plug 1 and the plug 1 according to the present invention
The results of actually using the attaching / detaching device 2 from the plug bar 12 and the automatic plug changing device will be described. In this example, the lifespan when rolling round steel slabs of carbon steel (TK15 class) is compared, but the conventional type attachment / detachment device (see FIG. 7) shows that after rolling an average of 5000 bare pipes, a tip steel ball is used. Twenty-three parts are damaged and unusable. On the other hand, in the case of the screw type according to the present invention, the amount of wear of the male screw 5 is slightly increased even after rolling 5000 times, which makes the conventional type unusable. There was no problem. However, if more than 7,000 raw tubes are rolled,
The degree of wear of the male screw 5 becomes large, and the plug 1 at the initial rolling stage
Since the centering property of is deteriorated, the eccentricity and thickness deviation of the tip end portion of the raw pipe deteriorate. As a result, the life of the screw type attachment / detachment device and the plug according to the present invention is about 1.4 times that of the conventional type. The situation is clear from FIG.

The plug exchange in the above embodiment was performed by 30% by hand and 70% by the automatic plug exchange apparatus according to the present invention, but compared with the case of using the conventional plug 1 and detachable device 2 even in manual exchange. With the plug 1 and the attachment / detachment device 2 according to the present invention, the work efficiency was good, and it was possible to carry out the replacement in 70% of the conventional replacement time. When using the automatic plug changer, the time is further shortened, which is equivalent to the replacement in about 60% of the time compared with the case of manual operation. Since the surface of the plug 1 can be checked by the highly sensitive ITV, all the work can be performed remotely in the piercer cab, and the labor of the plug replacement worker can be achieved.

[0019]

As described above, according to the present invention, the plug replacement is easier and the life of the plug attaching / detaching device is longer than that of the prior art, so that the efficiency of the plug replacing work and the remarkable reduction of the cost can be achieved. . Further, the use of the automatic plug changer further enhances the above effect and saves the replacement worker.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a plug according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a device for attaching and detaching a plug from a plug bar according to the present invention.

FIG. 3 is an assembly diagram in which the attaching / detaching device of FIG. 2 is inserted into a plug.

FIG. 4 is a diagram showing a dimensional relationship between the plug according to the present invention and the attachment / detachment device thereof.

FIG. 5 is a diagram showing an automatic plug changing device according to the present invention.

6 is a site layout of the automatic plug changer of FIG.

FIG. 7 is a diagram showing an example of a conventional plug attaching / detaching device.

FIG. 8 is a diagram for explaining the performance results of the present invention by the life of the plug attaching / detaching device.

[Explanation of symbols]

 1 Plug 2 Attachment / Detachment Device 3 Tip of Rod-like Member 4 Female Thread of Plug 5 Male Thread at Tip of Rod-like Member 6 Hollow (Space) 7 Tip of Plug Bar 8 Rear End of Rod-like Member 9 Screw at Rear-end of Rod-like Member 10 Robot hand 11 Slider 12 Plug bar 13 Robot arm 14 Palletizer 15 Pallet for supplying plug 16 Pallet for discarding plug 17 Aligning pusher 18 Cooling tank 19 Stripper conveyor 20 Plunger 21 Stopper pin 22 Coil spring 23 Steel ball 24 Small hole 25 Motor

Claims (4)

[Claims] 1. A bullet-shaped seamless steel pipe manufacturing plug having a hollow rear end, which is used for punching and rolling a round steel slab, wherein the hollow portion has a rod-shaped member of a plug attaching / detaching device on an opening side thereof. A seamless steel pipe for producing a seamless steel pipe, characterized in that a female screw that is screwed into the male screw at the tip is provided, and the inner portion of the hollow is larger than the diameter of the valley of the female screw and has a length longer than the female screw length. plug 2. The plug for producing a seamless steel pipe according to claim 1, wherein the plug simultaneously satisfies the following conditions. L ₁ ≧ (1/2) × L ₂ , φD ₁ ≧ (2/3) × φD
₂ , 0.5 mm ≤ Δd ≤ 1.0 mm, where L _{1 is the} length of the male screw at the tip of the rod member of the plug attaching / detaching device L ₂ : The total length of the plug φD ₁ : The inner diameter of the plug hollow portion φD ₂ : The plug attaching / detaching device Outside diameter of rod-shaped member Δd: clearance between screw part and straight part when plug is attached 3. Used for drilling and rolling a round steel piece and used for connecting and disconnecting a shell-shaped seamless steel pipe plug having a hollow rear end and a plug bar supporting the plug. A rod-shaped attachment / detachment device, the front half of which is a male screw that engages with the plug,
The latter half is a cylindrical shape having an outer diameter smaller than the thread diameter of the female screw and a length longer than the female screw length, and a screw for connecting and disconnecting with the plug bar is provided at the rear end portion. A device for attaching and detaching the plug to and from the plug bar. 4. An automatic plug changing device comprising: a robot hand for gripping a plug; a motor for rotating the robot hand about a plug axis; and a slider for moving the robot hand to a plug position. .