Electric drive facility, spindle, hot rolling mill, electric drive method, and method of producing hot rolled steel sheet

Abstract

To provide an electric drive technology having a protection function which can be applied to an existing facility and is excellent in introduction cost and maintainability.SOLUTION: An electric drive facility that includes a spindle having one end connected to an electric motor side and the other end connected to a driven device side, comprises: a torque sensor mounted on a surface of a cylindrical body constituting the spindle; a torque measurement device main body for supplying electric power to the torque sensor and collecting data from the torque sensor; abnormality determination means for determining the presence or absence of abnormality on the basis of the torque value of the spindle transmitted from the torque measurement device main body; and control means for performing predetermined abnormality avoidance measures to a drive system from the electric motor to the driven device when the torque value is determined to be abnormal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for preventing damage caused by an overload on a spindle in equipment that transmits driving force from an electric motor via a spindle. [Background technology]

[0002] A conventional method for overload protection of motor-driven equipment is an anomaly detection method using the motor's current value. In this method, known values ​​for the motor's output W, reference rotation speed N, and rated current value I0 are entered into the following formula 1, and the generated torque T is calculated by applying the feedback of the actual motor current value I, which is constantly measured. Based on the calculated torque, the motor is stopped immediately if abnormal torque is generated. There is also a method of providing a part called a shear pin, which protects other driving equipment including the spindle by breaking itself due to shear force when excessive torque is applied to the fastening part between the spindle and the driving equipment. (Formula 1) T = (974 W / N) (I / I0) Where, T: torque [kgf m] (× 9.8 Nm), W: motor output [kW] N: Reference speed [rpm] (1 / min), I: Actual current value [A], I0: Rated current value of the motor [A].

[0003] In recent years, there are also cases where a safety set is introduced between the spindle and the drive equipment or the electric motor as a protective device as described in Patent Document 1. This safety set seals hydraulic pressure into one of the double cylinders, and transmits torque to the other cylinder by frictional force generated by stress caused on the inner surface by the hydraulic pressure. When excessive load occurs, the sealed hydraulic pressure is released, and the frictional force generated between the inner and outer cylinders is released, causing the inner and outer cylinders to behave like a sliding bearing. This is a device that can stop torque transmission and prevent excessive load from being transmitted to the spindle or other drive equipment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-257382 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional techniques have the following problems. That is, in torque calculation based on the motor current value, the disturbance factor of the current value used in the calculation is large, and the cause of torque fluctuation is unclear. Therefore, it is difficult to capture detailed behavior such as torque fluctuation due to electrical noise rather than physical overload, and torque fluctuation due to torsional vibration generated when the drive shaft is loaded. In addition, the inertia moment of the motor and the inertia moment of other driving equipment act on the drive of the motor. Therefore, there is a problem that the calculated value is larger than the actual torque. In addition, the motor is located at the end of the input side of the drive system, and abnormalities due to overload are often caused by a malfunction on the output end equipment side to which the torque is transmitted. For example, if there is a rotating roll at the output destination, if the rotation of the roll is restricted for some reason, the overload is transmitted from the roll to the spindle and finally to the motor. Therefore, in control based on the motor current value, the load detection is delayed, and there are cases where the allowable torque that destroys the spindle is exceeded at the time the motor detects the overload.

[0006] As a protective device, the shear pin will not break under steady-state torque, but when excessive torque occurs, it must break under a load lower than the damage load of the spindle or other drive equipment. Therefore, in addition to the fact that it is extremely difficult to set the breaking torque of the shear pin, if the shear pin breaks, there is a problem that the connection between the spindle and the electric motor or surrounding drive equipment will be severed. If the connection breaks midway through the drive system, the spindle will swing around due to inertia, which may damage surrounding equipment, and it is also very difficult to restore the shear pin.

[0007] In addition, although the technology described in Patent Document 1 can be easily incorporated into new equipment, there are many problems with its introduction into existing equipment. For example, in order to introduce new component equipment between the faces of the driving machines, it becomes necessary to change the layout of each. Therefore, there is a problem that the introduction cost, including the cost of remodeling the existing equipment, becomes a considerably high investment.

[0008] The present invention has been made in view of the above, and aims to provide an electric drive facility and an electric drive method that can be applied to existing facilities and have a protection function with excellent introduction costs and maintainability, and also to provide a method for manufacturing hot-rolled steel sheets using the facility. [Means for solving the problem]

[0009] As a result of intensive research conducted by the inventors in order to achieve the above object, the inventors have discovered the following: That is, the inventors have discovered that it is possible to protect electric drive equipment by directly measuring actual torque and making it possible to determine overload based on the data.

[0010] The electric drive equipment of the present invention, which advantageously solves the above-mentioned problems, is an electric drive equipment having a spindle connected at one end to an electric motor side and at the other end to a driven equipment side, and is characterized in having a torque sensor installed on the surface of a cylindrical body constituting the spindle, a torque measuring device main body that supplies power to the torque sensor and collects data from the torque sensor, an abnormality determination means that determines the presence or absence of an abnormality based on the torque value of the spindle transmitted from the torque measuring device main body, and a control means that performs predetermined abnormality avoidance measures on the drive system from the electric motor to the driven equipment when the torque value is determined to be abnormal.

[0011] In addition, in the electric drive facility according to the present invention, it is a more preferable solution that the electric drive facility is a rolling facility, the driven equipment is a rolling mill, and the torque sensor is a non-contact strain gauge.

[0012] The spindle according to the present invention, which advantageously solves the above-mentioned problems, is a spindle provided in the electric drive equipment, one end of which is connected to the electric motor side and the other end of which is connected to the driven equipment side, and a torque sensor is installed on the surface of the cylindrical body. The hot rolling mill according to the present invention, which advantageously solves the above-mentioned problems, is characterized by having the above-mentioned spindle.

[0013] The electric drive method of the present invention, which advantageously solves the above-mentioned problems, is characterized in that, when transmitting the driving force of an electric motor to a driven device via a spindle, the torque of the spindle is directly measured, and when the obtained torque value exceeds a predetermined value (a torque threshold value for determining a torque abnormality), a torque abnormality is determined to have occurred, and specified abnormality avoidance measures are taken.

[0014] In the electric driving method according to the present invention, it is more preferable that the driven equipment is a rolling mill and the abnormality avoidance measure is the release of the load on the drive system from the electric motor to the driven equipment.

[0015] The method for producing a hot rolled steel sheet according to the present invention, which advantageously solves the above-mentioned problems, is characterized in that, using the above-mentioned rolling equipment, when a steel slab heated to a predetermined temperature in a heating furnace is hot rolled in a rolling mill, the torque value of the spindle is constantly monitored while rolling, and when the torque value becomes equal to or exceeds a predetermined value, it is determined that an abnormality has occurred and predetermined measures to avoid the abnormality are taken. Effect of the Invention

[0016] According to the electric drive equipment, the electric drive method, and the manufacturing method of hot-rolled steel sheet of the present invention, a torque measuring device capable of measuring actual torque is used, so that excessive equipment modification is not required, and even if the torque sensor breaks down, the torque sensor can be simply replaced, and there is no need to remove the drive system, and therefore the introduction cost and maintainability are excellent, making it industrially useful. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic conceptual diagram showing a configuration of a rolling facility as an electrically driven facility according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 4 is a flow chart showing a configuration of an abnormality avoidance measure implemented in the facility according to the embodiment. [Diagram 3] 1 is a graph showing an example of a transition between a torque value calculated from a current value of an electric motor and an actual torque value of a lead spindle connected to a rolling roll for a fifth stage rolling mill of a finishing mill. [Figure 4] 1 is a graph showing an example of changes in the torque value calculated from the current value of the electric motor and the actual torque value of the lead spindle connected to the rolling rolls for a second stage rolling mill of a finishing mill. [Diagram 5] 1 is a graph showing the distribution of actual torque and torque values ​​calculated from the current value of the electric motor for the second roll of a finishing mill. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. Note that the following embodiments are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and are not intended to limit the configuration to the following. In other words, the technical idea of ​​the present invention can be modified in various ways within the technical scope described in the claims.

[0019] Fig. 1 is a schematic conceptual diagram showing the configuration of rolling equipment as an electrically driven facility according to one embodiment of the present invention, Fig. 2 is a flow diagram showing the configuration of an abnormality avoidance measure implemented in the facility according to the above embodiment.

[0020] The rolling equipment 100 shown in Fig. 1 rolls a material 1 by passing it through a rolling mill 2. In the rolling equipment 100, the driving force of a main machine 7, which is an electric motor, is distributed to the upper and lower parts of the pinion stand 4 via a main reduction gear 6 and a lead spindle 5. Each driving force is transmitted to the rolling mill 2 via a universal joint spindle 3.

[0021] In this embodiment, a strain gauge 8A serving as a torque sensor is provided on the surface of a cylindrical body constituting the universal joint spindle 3 or the lead spindle 5. Data is then transmitted from the strain gauge 8A to the torque measuring device main body 8 in a non-contact manner.

[0022] In this embodiment, the torque values ​​measured by the torque measuring device main body are collected by a data logger 9, which is a measuring instrument, and transmitted to an anomaly detection system .

[0023] The anomaly detection system 10 selectively evaluates the torque value anomaly from other anomalies according to the flow in Fig. 2, and is incorporated into the rolling mill rapid stop procedure. In the example in Fig. 2, the abnormal phenomenon that is the target of automatic trouble detection (S12) is judged to be one of the following eight types (S09). S01: In the strip break determination, it is determined whether or not the rolled material 1 breaks during rolling. S02: In the bite delay judgment, the presence or absence of a bite failure of the rolling material 1 into the rolling mill 2 is judged. S03: In the guide deviation judgment, an abnormality due to meandering of the rolled material 1 is judged. S04: When the main engine speed is abnormal, it is determined whether the output of the electric motor 7 is within the rated output range. In S05: roll breakage, it is determined whether or not the rolling rolls constituting the rolling mill 2 are cracked or chipped. S06: Main engine digital thyristor abnormality (main engine semiconductor element abnormality) determines whether there is an abnormality in the main engine's digital thyristor panel (electronic components around the main engine). S07: In the actual value abnormality, it is determined whether the thickness, width, shape, etc. of the rolled material 1 after rolling are within a predetermined range. S08: It is determined whether the torque values ​​of the spindles 3 and 5 are abnormal as the actual torque abnormality according to this embodiment.

[0024] If automatic trouble detection S12, the pressing (ON) of the rolling machine emergency stop button S10 or the pressing (ON) of the coiler emergency stop button S11 (S13) is detected, and the rolling material 1 is being rolled by the rolling mill 2 (S14), emergency stop processing S16 is performed.

[0025] The predetermined abnormality avoidance measures in this embodiment refer to, for example, the following processing. The emergency stop process S16 includes the following processes: Forcibly remove the rolling material 1 being rolled (S17). Stop the rolling rolls of the rolling mill 1 while controlling the deceleration (S18). Release the roll pressure of the rolling mill 1 (S19). Emergency stop the hydraulic rolling (S20). Emergency stop the cooling water for the backup rolls (S21). Emergency stop the descaling device using high-pressure water (S22).

[0026] In this embodiment, since the actual torque of the drive shaft (spindle 3, 5) constituting the drive system is measured, the behavior of the torque fluctuation can be measured with higher accuracy than the current value of the electric motor 7. In the torque calculation based on the formula 1 using the current value of the electric motor 7, the current value generated during acceleration and deceleration becomes large due to the influence of the moment of inertia of the drive system and the main machine 7 themselves. Therefore, it was necessary to set the torque setting value for abnormality detection slightly higher to avoid false detection and unnecessary stops. In this embodiment, by measuring the actual torque, it is possible to ignore the influence of the moment of inertia required for the rotation of the main machine 7 and the drive system. Therefore, it is possible to set an appropriate setting value for torque abnormality detection. In addition, it is not necessary to set the setting value for torque abnormality detection higher as in the past. Therefore, it is possible to take a larger setting range for the allowable torque. Therefore, it is possible to set an appropriate management value for driving equipment that generates a wide variety of loads.

[0027] Furthermore, in this embodiment, an excessive load is detected at an earlier stage than the abnormality detection by the current value measurement, and a command to perform abnormality avoidance processing can be issued early. Therefore, it is possible to release the load before the allowable torque of the drive equipment is exceeded. Usually, the trouble of an excessive load that can occur in the drive system is often caused by foreign matter getting caught in the drive roll 2, not on the main machine 7 side, in the rolling equipment 100. In other words, since the excessive load often occurs at the end of the output of the drive system, if the main current of the electric motor 7 is measured, it will be at the farthest position from the equipment where the excessive load occurred. Therefore, when the excessive load reaches the main machine, the component equipment such as the drive shaft will have already been overloaded. On the other hand, measuring the actual torque in the middle of the drive system as in this embodiment makes it possible to detect the occurrence of an abnormality in torque near the source of the excessive load. Therefore, it is possible to issue an abnormality processing command such as an emergency stop to the electric drive equipment earlier than it is detected by the current of the electric motor 7.

[0028] In addition, this embodiment is excellent in that existing equipment is hardly modified and the maintainability of the drive equipment is not deteriorated. Safety devices such as the device described in Patent Document 1 require modification of the layout and dimensions of the existing drive system, so the introduction cost is very high. As for the shear pin, although the introduction cost is lower than the above-mentioned safety device, it has the following problems. Setting the release torque is extremely difficult, which requires design consideration costs. There is a high risk of false release during operation. Even if it operates normally and shears well, the unlucky spindle may fall and damage the surrounding area. Extraction of the shear pin and restoration work are extremely difficult. Therefore, the shear pin has very poor maintainability. In comparison with them, the actual torque monitoring technology according to this embodiment does not require any modification of existing equipment by introducing a torque measuring device. If the strain gauge, which is a torque sensor, is damaged, it is sufficient to simply replace the strain gauge on the cylindrical surface of the spindles 3 and 5. Therefore, there is no need to modify or change other devices in the drive system, and it has a very excellent effect in terms of introduction cost and maintainability.

[0029] Although the present embodiment has been described above with respect to the rolling equipment, the present embodiment is not limited thereto. The present embodiment can be applied to an electric drive equipment having a spindle connected at one end to the electric motor side and at the other end to the driven equipment side. In the present embodiment, a torque sensor 8A is provided on the surface of a cylinder constituting a drive shaft (spindle) that transmits the input torque of an electric motor located at an intermediate position of a drive system that is composed of a driven equipment that is a power transmission destination and an electric motor 7 that is a drive source. A torque measuring device main body 8 that supplies power to the torque sensor 8A and collects data from the torque sensor 8A is provided at a position that does not hinder the operation of the spindle. The torque measuring device main body 8 is incorporated into the abnormality detection system of the equipment as an abnormality determination means that determines the presence or absence of an abnormality based on the torque value of the spindle transmitted from the torque measuring device main body 8, and is constantly monitored. The present embodiment has a control means that performs a predetermined abnormality avoidance measure on the drive system from the electric motor 7 to the driven equipment when the torque value is determined to be abnormal. This control means is introduced as an excessive torque determination in the items for initiating the automatic protection function of the drive system by the abnormality detection system of the equipment, and is configured so that the drive equipment protection function can be activated by an appropriate system when the torque value deviates from a predetermined management value.

[0030] When the measured actual torque data is introduced into an operation anomaly detection system for constant monitoring, it is preferable to set the torque management value for judging an abnormality (torque threshold for judging a torque abnormality) in a range equal to or higher than the regular torque and equal to or lower than the allowable torque of the weakest part of the object to be protected, for example, the breaking stress. More preferably, it is set to 180% or less of the maximum regular torque. There is no particular lower limit for the maximum regular torque, but it should be set within a range in which normal torque is not erroneously recognized as an abnormality, for example, 50% or more of the maximum regular torque. However, this does not apply when 180% of the regular torque exceeds the breaking stress of the weakest part of the drive system.

[0031] Pulse-like noise may be mixed in when measuring torque. On the other hand, a pulse-like load due to an instantaneous impact, for example, an impact when the rolling material 1 is bitten in the rolling mill 2, may be 1.5 times or more of the normal torque, depending on the equipment structure and operating conditions. In order not to judge these torque values ​​as abnormal, it is preferable to judge an abnormality when a high torque value continues for a predetermined period. For example, it is preferable to judge an abnormal torque value when it continues for 0.05 s or more, which is the period of the torsional vibration torque. If the duration for judging an abnormality is set too long, excessive torque will occur for a long time, and there is a risk that the activation of the protective action will be delayed and the equipment will be damaged. Therefore, it is preferable to determine an appropriate value according to the operating conditions and the tolerance of the equipment. It is more preferable to calculate the torque rise rate in a certain period and set a management value for the rise rate to judge an abnormality. EXAMPLES

[0032] Using the hot rolling equipment of the equipment configuration shown in FIG. 1, a torque sensor 8A was installed on the lead spindle 5 to measure the actual torque. In the hot rolling equipment, a steel slab heated to a predetermined temperature in a heating furnace is hot rolled in a roughing mill and a finishing mill in that order to produce a hot rolled steel sheet. FIG. 3 is a graph showing an example of the transition between the torque value calculated from the electric motor current value and the actual torque value of the lead spindle connected to the rolling roll for the fifth stage rolling mill of the finishing mill. FIG. 4 is a graph showing an example of the transition between the torque value calculated from the electric motor current value and the actual torque value of the lead spindle connected to the rolling roll for the second stage rolling mill of the finishing mill. FIG. 3(a) and FIG. 4(a) show the transition of the rolling speed (strip speed). FIG. 3(b) and FIG. 4(b) show the transition of the torque value calculated from the electric motor current value by Equation 1. FIG. 3(c) and FIG. 4(c) show the actual torque value measured by a torque measuring device installed on the lead spindle.

[0033] As shown in Fig. 3(b) and Fig. 4(b), the torque T calculated from the current value of the motor increases with the acceleration a of the rolling speed (strip speed) due to the moment of inertia of the drive system. However, as shown in Fig. 3(c) and Fig. 4(c), the actual torque T is constant regardless of the acceleration or deceleration of the rolling speed. Therefore, except for the obvious peak noise Np in Fig. 4(c), it can be said that the application of this embodiment allows correct torque measurement in the steady state. The duration of the peak noise Np was 0.01 s or less.

[0034] FIG. 5 shows the distribution of maximum torque measured by repeating the same measurement as in FIG. 4 about 1500 times for the second stage rolling mill of the finishing mill. FIG. 5(a1) shows the distribution of maximum torque measured at the actual torque according to this embodiment when the rolled material is bitten. FIG. 5(a2) shows the distribution of maximum normal torque excluding when the rolled material is bitten at the actual torque according to this embodiment. FIG. 5(b1) shows the distribution of maximum torque calculated from the current value of the motor when the rolled material is bitten. FIG. 5(b2) shows the distribution of maximum normal torque excluding when the rolled material is bitten, calculated from the current value of the motor. FIG. 5 also shows the breaking stress of the lead spindle 5 as the allowable torque.

[0035] Comparing the torque at the time of biting in Figures 5(a1) and (b1), the maximum torque calculated from the motor current value is calculated to be low at about 70% of the actual torque. Therefore, it is clear that allowing the torque at the time of biting to approach the destructive torque of the lead spindle 5 using the torque calculated using the motor current value is dangerous because the actual torque will exceed the destructive torque. The reason for this is believed to be as follows. The impact generated in the rolling mill 2 is accurately measured by the actual torque measured by the lead spindle 5. However, since the electric motor 7 is installed at the most downstream of the drive system where this impact is transmitted, the impact is mitigated.

[0036] Comparing the maximum values ​​of normal torque excluding when the material is engaged, as is clear from Fig. 5(a2) and Fig. 5(b2), the maximum value of torque calculated using the current value of the motor (Fig. 5(b2)) is 1.8 times the maximum value of actual torque (Fig. 5(a2)). Despite the same rolling conditions, the difference between the maximum value of torque calculated using the current value of the motor and the allowable torque is smaller than that of the actual torque, and the setting range of the threshold value is narrower. It can be seen that with the method of this embodiment using the actual torque, the setting range of the control value is very wide, making it possible to set the control value in accordance with the operating conditions and equipment characteristics.

[0037] The spindle provided in the electric drive equipment specified in the present invention allows the electric motor to be stopped quickly when abnormal torque occurs. This makes it possible to prevent breakage due to shear force when excessive torque acts on the fastening part between the spindle and the drive equipment, and is economically effective in terms of equipment maintenance. Furthermore, the hot rolling mill having the spindle allows the electric motor to be stopped quickly when abnormal torque occurs. This makes it possible to prevent breakage due to shear force when excessive torque acts on the fastening part between the spindle and the drive equipment, and is economically effective in terms of equipment maintenance of the hot rolling mill. [Industrial Applicability]

[0038] The technology according to the present invention does not require excessive equipment modification, and when the torque sensor breaks down, it is only necessary to replace the torque sensor. There is no need to remove the drive system, and the technology is therefore industrially useful in terms of introduction cost and maintainability. In addition, the control value can be set in a very wide range, making it possible to set the control value in accordance with the operating conditions and equipment characteristics. [Explanation of symbols]

[0039] 100 Rolling equipment (electrically driven equipment) 1. Rolled material 2. Rolling mill (rolling rolls, driving rolls) 3 (Universal joint) spindle 4 Pinion Stand 5 (Lead) Spindle 6 Main reducer 7 Main engine (electric motor) 8 Torque measuring device body 8A strain gauge (torque sensor) 9. Measuring equipment (data logger) 10 Anomaly Detection System a acceleration xa Large fluctuation Tp Peak torque Np Peak noise t1 (rolled material) bite time t2 Acceleration start time t3 (Rolled material) strip removal time

Claims

1. An electric drive equipment having a spindle connected to an electric motor side and a driven device side, A torque sensor installed on a surface of a cylindrical body constituting the spindle; a torque measuring device main body that supplies power to the torque sensor and collects data from the torque sensor; an abnormality determination means for determining the presence or absence of an abnormality based on the torque value of the spindle transmitted from the torque measuring device body; and a control means for, when the torque value is determined to be abnormal, taking a predetermined abnormality avoidance measure for a drive system from the electric motor to the driven device.

2. The electrically driven equipment is a rolling equipment, the driven equipment is a rolling mill, The torque sensor is a non-contact strain gauge.

2. An electric drive installation according to claim 1.

3. A spindle provided in an electric drive installation according to claim 1 or 2, One end is connected to the motor side, and the other end is connected to the driven device side. A spindle with a torque sensor installed on the surface of the cylinder.

4. A hot rolling mill having a spindle according to claim 3.

5. When transmitting the driving force of the electric motor to the driven equipment via the spindle, Directly measuring the torque of the spindle; When the obtained torque value is equal to or greater than a predetermined value, it is determined that a torque abnormality has occurred. An electric drive method that takes predetermined abnormality avoidance measures.

6. The driven equipment is a rolling mill, 6. The electric drive method according to claim 5, wherein the abnormality avoidance measure is the release of a load on a drive system from the electric motor to a driven device.

7. Using the rolling equipment according to claim 2, When a steel slab is heated to a specified temperature in a heating furnace and then hot-rolled in a rolling mill, The rolling is performed while constantly monitoring the torque value of the spindle. When the torque value exceeds a predetermined value, it is determined that an abnormality has occurred. A manufacturing method of hot-rolled steel sheet, in which predetermined measures to avoid abnormalities are taken.

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