JP2001300622A - Rolling mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the defective rotation of guide rollers for guiding a material to be rolled to rolling rolls on the downstream side by the variation of pressure of oil-air with which the bearings of the rollers are lubricated. SOLUTION: The guide rollers 14 for guiding the material A to be rolled to the downstream side are provided between the rolling rolls 20, 21 inside a housing 13, oil-air pressure detecting devices 123 are provided on the supply passages 122 of the oil-air for lubricating these bearings and these detecting devices 123 are arranged outside the housing 13 and in the vicinity of it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling mill, and is used, for example, for hot rolling a material to be rolled, such as a bar or a bar.

[0002]

2. Description of the Related Art A rolling mill provided with a roller guide for guiding a material to be rolled to a caliber (hole type) formed on a rolling roll is disclosed, for example, in Japanese Utility Model Laid-Open No. 4-108907.
It is known in the publication. If rotation failure occurs in the roller guide, the size of the material to be rolled at high speed, defective shape, occurrence of scratches and the like, and cause factors such as misrolling, a guide roller rotation failure detection device is provided. I have.

In the technique disclosed in the above publication, a detection piece provided on a roller is detected by a proximity switch, and an electric signal corresponding to the number of rotations is taken out to determine whether or not the rotation of the guide roller is defective. . The rotation failure is determined to be failure when the rotation speed of the roller detected by the proximity switch falls below a predetermined value. In order to perform detection only during passing, a passing signal generator is provided.

[0004]

In the above-mentioned prior art, the detecting means is a rotation speed detecting sensor such as a photoelectric tube or a proximity switch provided close to the roller. There is a concern about erroneous detection or damage to the rotation speed detection sensor or the detection side, and thus it is not necessarily an accurate detection means. Particularly, in a hot rolling mill made of a strip steel or the like, since the detection means is located in the housing, the detection means is easily affected by heat, and rotation detection is not only inaccurate but also has problems in durability and the like.

Accordingly, the present applicant has proposed a technique employing a pressure detecting device (pressure sensor) using a pressure change as the rotation detecting means (see Japanese Patent No. 2955494). Although this proposed technique describes that a rotation failure of a roller guide (roll guide) can be detected without being affected by a use environment, the provision of the pressure detection device in a housing does not allow the rotation described above. Like the number detection sensor, the sensor is thermally affected. On the other hand, if the sensor is provided outside the housing, the above-described thermal effect can be reduced, but there is a possibility that the pressure detection is delayed (time delay).

The present invention solves the above-mentioned problem of the rotation speed detecting sensor by employing a pressure detecting device utilizing a pressure change of oil air for lubricating a bearing supporting the roller as a means for detecting a rotation failure of the guide roller. It is an object of the present invention to solve the problem and to prevent a delay in pressure detection while minimizing the thermal effect of the pressure detection device.

[0007]

According to the present invention, a rolling roll having a caliber is provided in a housing, and a guide roller for guiding a material to be rolled to the caliber is provided rotatably in the housing via a bearing. A rolling path for supplying oil air for lubricating the internal bearing from the outside to the internal bearing, and a pressure detecting device for detecting rotation failure of the guide roller based on a change in the pressure of the oil air in the rolling path; The following technical measures have been taken in order to achieve the aforementioned objectives.

That is, a rolling mill according to the present invention according to claim 1 is characterized in that the pressure detecting device is arranged outside the housing and in a supply path near the housing. By providing (arranging) the pressure detecting device in the supply path outside the housing in this way, the durability is improved while the accuracy of detection is secured while minimizing the thermal effect. By providing the detection device in the nearby supply path, maintenance of the detection device together with the rolling rolls, the guide rollers, and the like was facilitated while preventing rotation detection delay.

In the above-mentioned claim 1, it is recommended that the housing be provided with a plurality of rolling rolls in the flow direction of the material to be rolled (claim 2). The guide rollers are arranged in pairs so as to face each other with the material to be rolled therebetween, and supply paths for supplying oil air to bearings of the respective guide rollers are provided,
It is preferable that the pressure detecting device is provided in each supply path (claim 3). According to the third aspect, the rotation failure of the pair of guide rollers can be individually detected, which is advantageous.

Further, in any one of the above-mentioned claims 1 to 3, it is recommended that the material to be rolled is a strip steel, and the rolling roll is a finishing block mill or a sizing mill subsequent thereto. ).

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, a device and a method for monitoring a rotation failure of a guide roller (rotating body) are also disclosed. FIG. 1 shows a rolling equipment 1 for strip steel (wires, bars, etc.) to which the present invention is applied. The rolling equipment 1 has a heating furnace 2. In order to hot-roll the material to be rolled (workpiece) sent out from the heating furnace 2, the roughing mills 3, 1 An intermediate row rolling mill 4 and two intermediate row rolling mills 5 are arranged. The downstream side of the two intermediate row rolling mills is branched, one is provided with a winding machine 6, the other is provided with a finishing block mill 7, and the sizing mill 8 is provided following the finishing block mill 7. ing. A stellmore conveyor 9 is connected downstream of the sizing mill 8. In addition, the rolling equipment 1 includes a rolling operation room 10 for an operator to monitor and operate a rolling operation. The rolling operation room 10 is installed at a location away from other equipment of the rolling equipment 1.

FIG. 2 shows an example in which the rotating body defect monitoring device 11 is applied to the finishing block mill 7 and the sizing mill 8. The finishing block mill 7 has a main configuration in which a plurality of stands are arranged in a flow direction A1 of the material A to be rolled in a housing 13 having an inspection cover that can be opened and closed.
In this finishing block mill 7, eight stands are provided as shown in FIG. 3, and an upper / lower pair of rolling rolls 20 having an elliptical or square caliber 20A formed on the outer periphery and a circular caliber 21A are formed on the outer periphery. The left and right pair of rolls 21 are alternately arranged in the material flow direction A1, the upper and lower pair of rolls 20 are of a vertical type, and the left and right pair of rolls 21 are of a horizontal type. One block mill is constituted, and four sets of mills are shown in the figure.

A vertical stand and a horizontal stand on the downstream side form a set, and guide rollers 14 are provided between stands (mills) forming the set. That is, the guide rollers 14 are provided on the upstream side of the horizontal stand, respectively (total of four). These guide rollers 14 move the material A to be rolled having a corner or an ellipse on the upstream side into a horizontal stand on the downstream side (the circular caliber 2 of the rolling roll 21).
1A) to stably supply (induce) hot steel. The guide roller 14 is provided with an upper guide roller 14a and a lower guide roller 14b at each position,
Upper and lower guide rollers 14a and 14b are provided in pairs so as to face vertically with the material to be rolled therebetween. Although the guide roller 14 is not driven, during high-speed rotation by the hot steel, a rotation failure such as seizure of a bearing sometimes occurs to induce poor quality or misroll.

For this reason, oil air is supplied to a bearing (bearing) rotatably supporting the guide roller 14 to lubricate the bearing (details will be described later). The sizing mill 8 also has a stand 1 on the housing 16.
The stand is also provided with a guide roller 14 for stably supplying the material to be rolled.
In the following, among the stands provided in the finishing block mill 7, the stands (mills) provided with the guide rollers 14 for guiding the material are referred to as "stands 22st" and "stand 22" from the upstream side in the material flow direction. Stand 24st ",
They are called “stand 26st” and “stand 28st”.
In addition, the stand of the sizing mill 8 is referred to as “Stand 30s
t]. The positions of the guide rollers are not limited to those described above, and may be arranged, for example, as left and right pairs.

FIGS. 4 and 5 show the guide roller 14. FIG. The guide roller (hereinafter, referred to as a roller guide) 14 includes a roller 101 having a caliber for guiding a material A to be rolled formed on an outer peripheral surface thereof. A collar 102 is formed at a central portion of an inner peripheral surface of the roller 101. The ball bearing 104 can be accommodated on both sides thereof. Roller 1
The roller shaft 107 of 01 is a bolt shape, and a shoulder 112 for receiving the ball bearing 104 is formed on the head 110 side,
A screw for screwing the nut 108 is formed at the tip. A supply hole 111 for supplying lubricating oil (oil air) to the ball bearing 104 is formed in the center of the shaft from the head 110 side to the center of the shaft, and communicates with a supply hole 11a formed in the center of the shaft in the radial direction. ing.

The roller 101 is supported by a roller support main body 105. The support main body 105 has, at one end, roller shaft support members 106, 106 formed at two ends with a wider interval than the thickness of the roller 101. A hole 109a for mounting the roller shaft 107 is formed in the support members 106, 106, and the head 110 of the roller shaft 7 is non-rotatably accommodated in the one roller shaft support member 106 from the outer surface side. The other roller shaft 106 has a hole 9b for rotatably receiving the nut 108 from the outer surface side.

Between the roller 101 and the roller shaft 107,
A spacer ring 116 is provided. The spacer ring 116 is slightly thinner (about 0.5 mm) than the thickness of the flange 102 at the center of the inner peripheral surface of the roller 101 and slightly smaller than the outer diameter of the roller shaft 107. Donut plate-shaped small-diameter spacer ring 117 with a large (about several mm) inner diameter
And a large-diameter spacer ring 118 having an inner diameter slightly larger than the outer diameter of the small-diameter spacer ring 117 (about 0.5 mm) and substantially the same thickness as the thickness of the flange 102 at the center of the inner peripheral surface of the roller 101. In the center of the thickness of the small-diameter spacer ring 117, a through hole 119 is formed in the radial direction.
On the other hand, a groove 120 is formed in the inner periphery of the large-diameter spacer ring 118.

The guide roller having the above structure is assembled in the following procedure. The ball shaft 104 is inserted from both sides of the roller 101 such that the large-diameter spacer ring 118 is non-rotatably fitted to the inner periphery of the collar 102 of the roller 101 and the small-diameter spacer ring 117 is sandwiched between the inner rings of the ball bearing 104. : The roller support body 1 assembled as described above
The roller shaft 107 is inserted between the roller shaft supporting members 106 and 106 of the roller shaft 05, and the roller shaft 107 is inserted through the side surface of the roller shaft supporting member 106 on the hole 109 side. Inner ring and roller shaft support member 1
06 and the bearing holding ring 113 is inserted. : Roller shaft supporting member 1 after inserting roller shaft 107
The spring washer 114 is inserted through the hole 109b of the roller 06 through the roller shaft 107, and the nut 108 is tightened. As a result, the small-diameter spacer ring 117 is fastened between the inner rings of the two ball bearings 104 and is non-rotatably mounted on the roller shaft 107, and has a space 21 communicating with the supply hole 111 a and the through hole 119 between the roller shaft 107. Is formed. : Next, a pipe 122 for supplying oil air is connected to the supply hole 111 of the head 110 of the roller shaft 107, and a pressure detecting device 123 is connected in the middle of the supply pipe 122. An oil-air supply pipe 122 is provided in each of the roller guides 14, and each pipe 122 is provided with a pressure detection device 123. Pressure detector 123
Are provided outside the housings 13 and 16 to avoid the influence of heat. Further, the pressure detecting device 123 is provided near the housings 13 and 16 to prevent delay in pressure detection, and when performing repair inspection of a mill in the housings 13 and 16, the pressure detecting device 123 is also provided.
Is also convenient to check. .

The roller guide 14 constructed as described above
Then, the oil air supplied through the pipe 122 is supplied to the ball bearing 104 through the supply holes 111 and 111a, the space 121, and the through hole 119. In this supply process, when the roll (roller) 101 rotates, the large-diameter spacer ring 118 rotates with the rotation, whereby the groove 120 formed in the large-diameter spacer ring 118 becomes a through-hole formed in the small-diameter spacer ring 117. 119 is opened and closed. The pressure detector 123 detects a change in pressure at the time of opening and closing. Further, since the pressure detecting device 123 is provided corresponding to the plurality of roller guides 14, it is possible to detect a pressure fluctuation due to the rotation of each roller guide 14.

The pressure fluctuation of the oil air is controlled by the roller guide 1.
4 times per 4 revolutions. FIG. 6 shows a pressure detector 1
23 shows a signal waveform of the pressure fluctuation detected. As shown in FIG. 6A, the groove 120 of the large-diameter spacer ring 118 is used.
When opening the through-hole 119 formed in the small-diameter spacer ring 117, the pressure in the conduit 122 decreases. On the other hand, FIG.
When the through hole 119 is closed as shown in FIG.
The pressure at 22 increases. The signal of the pressure fluctuation changes depending on the rotation angle of the roller guide. That is, this signal has a frequency proportional to the rotation speed of the roller guide 14. In FIG. 6, two cycles of the pressure fluctuation correspond to one rotation of the roller guide 14.

The pressure fluctuation signal output from the pressure detector 123 is amplified by the amplifier 35 and
Given to. Note that the amplifier 35 is provided on a local device storage panel 36 installed near the finishing block mill 7 or the like. The control device 37 is installed in the rolling cab 10. As shown in FIG. 7, the pressure detecting device 123, the amplifier 35, the high-pass filter 38 described later, and the like constitute an input unit of the monitoring device 11. The control device 37 includes, in addition to the high-pass filter 38, an A / D converter 39 for converting a pressure fluctuation signal, which is an analog signal, into a digital signal, and a computer (general-purpose personal computer) connected to the A / D converter 39 40. The computer 40 includes a display device as a display device 40a. The computer 40 is communicably connected to a rolling line master control device 41 which is a rolling control device 41 for controlling the rolling line, and can exchange information with the rolling control device 41.

The computer 40 includes a low-pass filter unit 4 for filtering the A / D converted data.
3.FF which performs FFT conversion of the filtered data
T conversion unit 44 and rotation failure determining unit 4 for determining rotation failure
5 is held. The low-pass filter unit 43 and the FFT conversion unit 44 include an A / D converter 39
Together, they constitute a signal processing unit. In addition, since the rotation speed (rotation speed) of the roller guide is detected by each function from the pressure detection device 123 to the FFT conversion unit, these functions constitute the rotation speed detection unit 33 according to the present invention. become.

FIG. 8 shows the flow of the monitoring process by the monitoring device 11. First, when the device 11 is started, the system is initialized. Then, the state of the rolling line is determined. The line state determination includes a metal-in determination and a use stand determination. Metal-in determination is a determination of whether or not the material to be rolled is on the line,
The determination result is used to display whether monitoring is in progress or on standby on a monitoring status display screen described later. If there is no material to be rolled, monitoring is unnecessary and it is only necessary to wait.

The determination of the used stand is performed to monitor the used stand and display it on the screen. The stand used is changed depending on the change of the rolling size and the product quality. For example, for one type of rolling, all stands 22st, 24st, 26st, 28s
While t, 30st is used, for other types of rolling,
In some cases, only some of the stands 22st, 24st, 30st are used. For still other types of rolling, some other stands 22st, 24st, 28st may be used. Since the stands that are not used do not have the rolling rollers and the roller guides 14, the monitoring of the roller guides 14 is unnecessary.

The rolling stand information for each rolling method is stored in the memory of the rolling control device 41 as a data table, and the monitoring device 11 fetches the used stand information from the rolling control device 41, Recognize the stand to be monitored. Therefore, even if the stand configuration is changed due to the change in the rolling size, only the used stand is automatically diagnosed. When the monitoring of the roller guide 14 is started, the pressure fluctuation analog signal output from the pressure detection device 123 is filtered by the high-pass filter 38, applied to the A / D converter, and converted into digital data. This digital data is stored in the memory of the computer 40. This digital data is filtered by the low-pass filter 43, and is subjected to FFT by the FFT conversion unit.
FT analysis is performed. The rate of change of the pressure fluctuation is very high (rotation speed of the roller guide: 20,000 to 30,000 rpm), so that it is difficult to handle the raw data as it is, but the FFT analysis facilitates the handling.

A frequency component of the pressure fluctuation is obtained by the FFT analysis, and a roller rotation detecting process is performed based on the frequency component. By this processing, the main component (first-order component) frequency of the pressure fluctuation is obtained. Note that the principal component frequency is generally the highest level frequency, and
It can be obtained by creating a peak list and a harmonic list from the data after the T conversion, etc. However, since it is a known method, the description is omitted. When there is no main component, rotation is not monitored. When this processing is performed, the frequency (principal component frequency) of the pressure change of the oil air generated by the rotation of the roller guide 14 as shown in FIG. 9B is obtained from the collected data of the pressure fluctuation as shown in FIG. Is required. This pressure change frequency indicates the rotation state of the roller guide 14, and if the rotation of the roller guide 14 decreases or stops, it appears as a decrease in frequency.

The poor rotation judgment section 45 performs a poor rotation diagnosis based on the frequency component of the pressure fluctuation. Judgment for failure diagnosis is based on a judgment based on the rotational speed difference of each roller guide,
It is performed by using the rotation stop determination based on the frequency distribution together. Is determined by comparing the frequencies of the signals detected by the pressure detection devices 123 provided corresponding to the upper and lower roller guides 14a and 14b, which form a pair across the material to be rolled. This comparison is performed by calculating a difference between the main component frequency obtained for the upper roller guide 14a and the main component frequency obtained for the lower roller guide 14b. The difference is calculated by calculating a difference = (principal component frequency A−principal component frequency B) when the larger one of the two principal component frequencies to be compared is the principal component frequency A and the smaller one is the principal component frequency B. / (Main component frequency) × 100 (%).

For example, as shown in FIG. 10, when the main component frequency of the upper roller guide 14a is 300 Hz and the main frequency component of the lower roller guide 14b is 320 Hz, the difference is calculated as 6.25%. Is done. According to this determination method, it is possible to immediately determine that the rotation is abnormal when any one of the roller guides 14 to be compared with has its rotation speed decreased or stopped. Further, unlike the related art, a reference value corresponding to the passing speed of the material to be rolled is not required. If the calculated difference exceeds a predetermined range, a rotation difference occurs between the upper roller guide 14a and the lower roller guide 14b, and it is determined that the rotation is defective. The predetermined range reference value for determining whether or not the difference is within the allowable range is set in advance in the rotation failure determining unit 45, but it is preferable that the setting can be manually changed to change the accuracy. It is preferable that the setting can be changed for each roller guide or each stand.

The rotation stop determination of the pressure detection device 123
This is performed based on the frequency component of the signal detected at. Based on the result of the frequency analysis, the frequency components are arranged in order from the one with the highest level, and the one with the highest level (the main component) is compared with the one with the Nth highest (the low-level component). If the ratio of the low-level component to exceeds the predetermined ratio set in advance, it is determined that the rotation of the roller guide 14 is stopped. It has been empirically found that when the rotation of the roller guide 14 stops, the level of the main component decreases and the noise increases. Therefore, it is intended to use this to detect the rotation stop. . According to this determination method, it is not necessary to compare the rotations of the plurality of roller guides 14. Therefore, even if all the roller guides 14 are stopped, it is possible to reliably determine the rotation failure. Therefore,
By combining this with the determination of, the rotation failure can be determined more reliably.

FIG. 11 shows a case where the upper roller guide 14a rotates normally and the lower roller guide 14b stops. In FIG. 10, the frequency components obtained by the FFT transform are arranged in order from the highest frequency level to the lowest frequency level. That is, the component with the highest level located on the left side in FIG. 11 is the principal component frequency,
They are arranged so that the level becomes smaller as going to the right. As shown in FIG. 11A, since the upper roller guide 14a rotates normally, the main component is large and the difference from the Nth (14th in the figure) component is sufficiently large. The level ratio of the Nth frequency component to the main component is 6%. If the ratio is small, it is determined that the rotation is normal.

On the other hand, as shown in FIG. 11B, since the lower roller guide 14b is stopped or stopped, the level of the main component decreases, and conversely, the low-level component increases due to noise. The difference is smaller. Here, the level ratio of the Nth frequency component to the main component is 25%. Since this level ratio is high, it is determined that the rotation of the main component is poor due to a decrease in the level of the main component. In addition, a ratio (predetermined ratio) that is a reference of whether the rotation ratio is good or bad
Is set in advance in the rotation failure determination unit 45, but it is preferable that the setting can be manually changed to change the accuracy. It is preferable that the setting can be changed for each roller guide or each stand. It is also preferable that the value of N can be manually changed.

The result of the rotation failure determination described above is always
It is displayed on the monitor display screen 50 of the display device 40a.
The screen 50 includes a monitoring stand status display section 51 for displaying a stand to be monitored (used stand), and a current monitoring state display section for displaying the current monitoring function in a standby state or a monitoring state. 52, a monitor setting item display unit 53 for displaying the value of a setting item for monitoring, a stand status display unit 54 for displaying a graph of the status of each stand being monitored, a latest abnormality for displaying the latest abnormality information when an abnormality occurs. An information display unit 55 is included.

The stand 14 currently used is displayed on the monitoring stand status display section 51 based on the used stand information. In FIG. 12, all the stands “22, 24, 26, 28, 30” are displayed,
This indicates that all stands are being used and are being monitored. Also, for example, if the used stand is “22s
If it is changed to “t, 24st, 30st”, “22, 24, 30” is displayed on the stand state display section 51. The current monitoring state display section 52 displays the result of the metal-in determination. If monitoring is unnecessary and there is no material to be rolled, "waiting" is displayed as shown in FIG. For example, "monitoring" is displayed.

The stand status display section 54 graphically displays the status of each stand currently used based on the used stand information. In FIG. 12, since all the stands are used, the states of all the stands are displayed. The contents of the displayed graph are the main components of each of the upper roller guide 14a and the lower roller guide 14b. When it is determined by the rotation failure determination unit 45 that the rotation is defective, an abnormality process is performed. The abnormal process includes an abnormal alarm process and an abnormal data storage process. In the abnormality alarm processing, the stand 14 in which the abnormality has occurred is highlighted on the screen 50 and a buzzer sounds to warn the user. The operation of the rotation failure determination process is continued even after the occurrence of the abnormality.

In the abnormal data saving process, data such as the data after the FFT conversion, the date and time of occurrence of the abnormality, and the stand number of the occurrence of the abnormality are stored in a storage unit such as a hard disk of the computer. FIG. 13 shows the case where the upper and lower roller guides 14a and 14b rotate normally, and FIG. 14 shows the lower roller guide 14b.
7 specifically shows the state of the data after the FFT conversion in the case where is stopped. In the case of FIG. 13, the upper roller 14a
Is 180 Hz, and the main component frequency of the lower roller 14b is 183 Hz. Since the difference between the two frequencies is small, it is determined to be normal.

On the other hand, in the case of FIG.
The main component frequency of a is 180 Hz, and the main component frequency of the lower roller 14b is 361 Hz. Since the difference between the two frequencies is large, it is determined that the rotation is defective or stopped. Also, it can be seen that the level of the main component frequency has decreased and the level of the opposite noise has increased. Note that the present invention is not limited to the above embodiment.

[0037]

According to the present invention, it is possible to judge a rotation failure of a rotating body without using a reference rotation speed that changes depending on the speed of a workpiece.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a rolling facility to which the present invention is applied.

FIG. 2 is a schematic view of an apparatus when the present invention is applied to a finishing block mill and a sizing mill.

FIG. 3 is an explanatory sectional view of a roller guide.

FIG. 4 is a configuration diagram of a finishing block mill.

FIG. 5 is a sectional view taken along line XX of FIG. 4;

FIG. 6 is an explanatory diagram showing a relationship between a rotation state of a guide roller and a pressure fluctuation signal.

FIG. 7 is a device schematic diagram including a detailed configuration of a control device.

FIG. 8 is a flowchart showing a flow of processing of the monitoring device.

FIG. 9 is an explanatory diagram illustrating that a frequency of a pressure change is obtained by FFT analysis from a signal detected by the pressure detection device.

FIG. 10 is an explanatory diagram of a rotation failure determination method based on a rotation difference.

FIG. 11 is an explanatory diagram of a rotation failure determination method based on a frequency distribution.

FIG. 12 is an explanatory diagram of a monitoring status display screen.

FIG. 13 shows data after FFT conversion in a normal state.

FIG. 14 shows data after FFT conversion when the lower roller stops.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling equipment 7 Finishing block mill 13 Housing 14 Roller guide 20, 21 Roll roll 123 Pressure detector

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukihiro Kanda 2 Nadahama-Higashi-cho, Nada-ku, Kobe City, Hyogo Prefecture Inside Kobe Steel, Ltd. Kobe Steel, Ltd. Kobe Works F-term (reference) 4E002 AC12 AC14 BB06 BC08 CA19 CB03 CB09

Claims (4)

[Claims] 1. A rolling roll having a caliber is provided in a housing, and a guide roller for guiding a material to be rolled to the caliber is rotatably provided in the housing via a bearing.
A supply path for supplying oil air for lubricating the bearing from the outside of the housing to an internal bearing; and a pressure detection device for detecting a rotation failure of the guide roller based on a change in the pressure of the oil air. In a rolling mill, the pressure detecting device is arranged outside the housing and in a supply path near the housing. 2. The rolling mill according to claim 1, wherein a plurality of rolling rolls are provided in the housing in a flow direction of the material to be rolled. 3. The guide rollers are arranged in pairs so as to face each other with the material to be rolled therebetween, supply paths for supplying oil air to bearings of the respective guide rollers are provided, and the pressure detection devices are respectively provided. 3. The method according to claim 1, wherein the supply path is provided in a supply path.
The rolling mill as described. 4. The rolling mill according to claim 1, wherein the material to be rolled is a strip steel, and the rolling roll is a finishing block mill or a sizing mill subsequent thereto.