JPH084225Y2 - Squeeze roll for ERW pipe manufacturing - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeeze roll for producing electric resistance welded pipe.

[0002]

As is well known, in the manufacture of ERW pipe,
The edges of the steel strip to be welded are heated by electrical resistance or induction and then squeeze rolls are continuously butt welded while providing upset. The expanded use of ERW pipes manufactured in this way has been remarkable in recent years, and the trend toward higher grades has further strengthened accordingly, and the materials used for steel strips have rapidly changed to higher tension and thinner walls. I'm doing it. In order to deal with this, improvement of welding quality is required, and dry pipe making is being studied as one of the countermeasures. The squeeze roll for electric resistance welded pipe is located very close to the welded portion, and is internally heated to a high temperature by the induction action of the high frequency current for welding. This causes seizure and deterioration of the roll material. As a countermeasure against this, cooling of the roll surface portion is required, and conventionally, water has been discharged to the outer surface of the roll for cooling. However, according to this method, the external cooling water may be scattered on the welded portion, which may cause welding defects due to local cooling. In addition, the atmosphere near the welded portion (sealing with argon or nitrogen to prevent oxidation at the welded portion) is not stable, which causes deterioration of the welding quality.

Further, recently, the number of pipe-making lines using laser for welding has increased, and external cooling water causes refraction of the optical path, so that it cannot be said to be an appropriate roll cooling method. Therefore,
As a countermeasure, an internal water-cooled roll that cools from the inside without using cooling water from the outside has come to be used. recent years,
Internal water cooling rolls are being developed at each company,
The reality is that complete dry pipe making with a small-diameter 4-roll is not performed. Complete drying is only partially performed in the two-roll pipe forming in which only the side rolls are used without using the above-mentioned top rolls. Further, in the case of a four-roll pipe, a method is adopted in which only the top roll is subjected to internal water cooling and the outside water is cooled to the extent that it does not scatter to the side rolls that are a little distance from the welded portion. However, it is impossible to completely remove the cooling water from the welded portion, and it cannot be said that the true purpose of the dry pipe making has been fulfilled unless the cooling water is not supplied from the outside as the basic structure.

Now, the details regarding the prior art will be described. First of all, the side rolls are roughly classified into two types of cooling mechanisms. One is a structure that uses an oil seal to form a water channel. Two water channels are passed inside the shaft, one is aligned with the shaft core and the other is installed in parallel and off the core. This 2
In the case of the second one, since the roll rotates, it is not possible to simply connect the shaft side and the roll side, and water from the shaft is injected once into the pool on the inner circumference of the roll, and then from a part of the pool to the roll end. The method said to pour is taken. in this case,
Since the oil seal has a large rotational resistance, it is suitable for a large-diameter pipe with a large molding reaction force, but a small-diameter pipe may cause scratches and is not a very preferable mechanism. Moreover, complete waterproofing is difficult only with oil seals,
This results in leakage of water to the outside and a decrease in cooling efficiency.

The second conventional mechanism incorporates a rotary joint and has no sliding portion in the cooling water passage, and is one step superior to the above-mentioned mechanism in terms of sealing property. The rotary joint has a double pipe structure, and water is supplied from the inside and drained from the outside. For this reason, it is possible to align the two water channels with the shaft center, and a very simple structure can be assembled. It is also suitable for small-diameter pipes that have a relatively small rotational resistance and a small molding reaction force. However, if there is a bearing inside the roll, the method disclosed in JP-A-2-
As described in Japanese Patent No. 25285, a water channel must be installed between the bearings, which is very difficult to configure in the case of a small diameter roll, and it is considered that the life of the bearing is shortened due to water leakage. Therefore, as in JP-A-1-148416, a structure is adopted in which water is supplied from the upper part of the roll. However, with this structure, a huge protrusion is attached to the upper surface of the roll, and it is almost impossible to install the top roll. Therefore, only 2-roll dry pipe making with only side rolls can be performed.

Next, the top roll will be described. The top roll basically has the same mechanism as the side roll. However, in this case, there is a space restriction, which is an obstacle in considering the configuration. The most difficult to construct is the bearing support method. When mounting the bearings outside the rolls, they interfere with each other on the line center side, and it is impossible to mount them on rolls with a small diameter. At present, a structure in which a bush is used as a test substitute or a bearing is fitted by shaving the outside of the roll is considered, but it has not been realized yet. In this way, it is considered very difficult to achieve internal water cooling for both topside rolls. These are the reasons why the 4-roll dry pipe making is not done at present.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a squeeze roll having a small diameter, which is advantageous in solving problems of installation space and difficulty of internal cooling due to the small diameter of a top roll. It is a thing.

[0008]

SUMMARY OF THE INVENTION The gist of the present invention is a four-scroll squeeze roll for producing electric resistance welded pipes, in which the top roll is a cantilever mechanism and the cooling water supply passage and the key in the top roll are provided in the same cross section. This is a squeeze roll for producing electric resistance welded pipes. That is, by adopting rotary joints for both side rolls and top rolls, it has a compact structure that prevents water leakage and scratches due to rotation resistance and does not occupy a wasted space. It was incorporated. Generally, the cantilever mechanism tends to be shunned in terms of rigidity and play, but with a small-diameter roll for thin-walled products, the molding reaction force is small, and it may be difficult to secure bearing space on the line center side. Adopted. The next point to note is that the cooling water supply passage and the key in the roll were overlapped in the same cross section. When supplying cooling water through the shaft, a water channel will be installed between the shaft and the roll, and an O-ring must be installed to prevent water leakage. Therefore, it is common to adopt a structure in which the waterway and the key are independent.
As a result, if the wall thickness of the roll becomes large and the side roll becomes particularly thick, it may be impossible to attach the top roll. Therefore, the key and the cooling water channel are installed in the same cross section, and O-rings are attached above and below the key. Further, since all the squeeze rolls are idle rolls, and the torque acting on the keys and splines is only the rotational resistance due to the bearings and rotary joints, there is no problem regarding strength and life.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described in detail with reference to FIGS. A roll holder 1 supports a bearing 2. The top roll 12 is generally supported on both sides, but in the case of a small diameter roll, it interferes with the opposing top roll on the line side, so it is supported by a cantilever and the conical roller bearing is attached to one side of the roll as in 2. It is provided and fixed to the holder 1. At this time, in order to reduce the load applied to the bearing 2, the distance between both bearings is set as large as possible in terms of the structure. 11 is a key, which transmits the shaft power to the roll,
To make the roll thinner, it has the same cross section as the cooling water channel. Then, the member 3 is fastened with bolts to fix the bearing and the oil seal 4. Further, the rotary joint 5 is connected to the inside of the shaft as shown in the figure, and the water supply passage 6 and the drainage passage 7 of the joint are aligned with the shaft core 13 and piped to the communication port of the in-roll water passage. The cooling water supplied from the joint passes through this pipe, and is poured into the roll inside 8 from the water supply port provided at the tip of the shaft. After exiting the water supply port 9, the roll is branched into two directions, left and right, and flows through the cooling water channels 180 degrees, respectively.
It is drained through the drainage port 10.

It is preferable that the cooling water passage has as large a surface area and volume as possible to increase the amount of heat absorption. But,
If the diameter of the water channel is large, stagnation will occur, so the shape was wavy as shown in the figure. The cooling water flows right and left in the in-roll water passage, and is then drained to the rotary joint. The above description applies to the top roll and the side rolls.

It should be noted that this invention is not limited to the above-described embodiment, but includes all matters in accordance with the technical idea of this invention. In addition, there is a case where the top roll of the present invention is subjected to a molding reaction force at the tip to cause the top roll to be tilted, but it is necessary to apply a preload to the shaft part on the opposite side in advance to eliminate the tilt of the top roll. Is more advantageous.

[0012]

As described above, the conventional internal water-cooled roll mechanism could not be adapted to the small diameter squeeze, whereas the roll of the present invention can be dry-formed by cantilevering and reducing the roll thickness. It enables pipes and can be expected to improve welding quality.

[Brief description of drawings]

FIG. 1 is a partial explanatory view of a squeeze roll of the present invention.

FIG. 2 is an explanatory view showing a cooling water supply passage in the top roll of the present invention.

[Explanation of symbols]

 1 Roll Holder 2 Bearing 3 Member 4 Oil Seal 5 Rotary Joint 6 Water Supply Channel 7 Drainage Channel 8 Inside Roll 9 Water Supply Port 10 Drainage Port 11 Key 12 Top Roll 13 Shaft Core

Claims (1)

[Scope of utility model registration request] 1. A four-roll squeeze roll for producing electric resistance welded pipe, wherein the top roll has a cantilever mechanism, and a cooling water supply passage in the top roll and a key are provided in the same cross section. Squeeze roll.