Rolling machining system and abnormality monitor method of rolling device

Abstract

To provide a rolling machining system and an abnormality monitor method which quickly discovers the occurrence of such abnormality as abrasion of roll dies and processing failure of a work piece.SOLUTION: A rolling machining system TS includes a rolling device 10 which rolls a thread of a screw so as to put a workpiece W between roll dies 14, an AE sensor 50 which is arranged on a mounting base part 32L of the left side roll die 14L and measures acoustic emission of the roll die, a calculation part 81 which calculates an average AE energy Vaveeng corresponding to a deformation amount of a workpiece by means of the rolling device based on a measuring result of the AE sensor and an abnormality judging part 82 which detects the occurrence of abnormality based on the average AE energy Vaveeng.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a rolling system including a rolling device having a roll die, and a method for monitoring an abnormality in the rolling device. [Background technology]

[0002] Conventionally, rolling devices that press a roll die into a workpiece (workpiece) to form threads have been known. Patent Document 1 below describes a rolling device having a roll die, in which a servo motor, which is the drive source for rotating the roll die, and a torque sensor are disposed on the die rotation drive shaft to detect the rotation torque of the roll die, and a servo pump of a roll die pressing device is controlled so that this rotation torque forms an appropriate pattern. The technology described in this document is said to be able to prevent the rotation torque of the roll die from becoming abnormally high, keep the load on the roll die within an allowable range, and extend the life of the roll die.

[0003] Furthermore, in the field of cutting work, there has been known a technique for detecting deterioration of a machine tool that performs cutting work by using an AE sensor to detect acoustic emissions generated in a cutting tool during cutting work (see Patent Document 2 below). In the deterioration amount detection method described in Patent Document 2 below, an AE sensor is provided on the machine tool that performs cutting work, and the amount of deterioration of the cutting tool is calculated based on a value obtained by excluding from the measurement value (output voltage) of the AE sensor a change in the detection sensitivity of the AE sensor that corresponds to a change in the temperature of the cutting tool. This technique is said to enable accurate detection of the amount of deterioration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-82634 [Patent Document 2] Patent No. 7304956 Summary of the Invention [Problem to be solved by the invention]

[0005] In the manufacture of rolled bodies such as screws using a rolling device, the rolling device is often operated day and night. Therefore, roll dies wear out relatively quickly even under normal use. If a rolling device is operated overnight without noticing roll die wear, a large number of defective rolled bodies may be produced. Therefore, it is desirable for manufacturing workers to be able to quickly identify suspected processing defects or roll die wear. While the rolling device described in Patent Document 1 is expected to extend the life of the roll dies, it is difficult to quickly detect abnormalities such as roll die wear or processing defects. Because gears are interposed between the roll dies and the servo motor, even if the rotational torque is detected, the rotational torque does not fully reflect the processing status of the workpiece.

[0006] Furthermore, while the deterioration detection method described in Patent Document 2 can calculate tool deterioration, it is a technology that uses an AE sensor to calculate tool deterioration in the field of cutting, in which a portion of a workpiece is removed with a cutting tool. In the field of cutting, changes in the condition of the cutting tool's cutting edge appear as changes in its sharpness relative to the workpiece. This change in sharpness significantly changes the amplitude of the acoustic emissions (AE sensor output voltage) generated by the cutting tool, so cutting tool deterioration can be detected by monitoring the AE sensor output voltage. In contrast, in rolling, a die is forced into the workpiece to plastically deform it. Therefore, the amplitude of the acoustic emissions generated by the die during rolling does not clearly reflect the deterioration of the die or the processing status of the workpiece, as in the field of cutting. In other words, monitoring only the amplitude of the acoustic emissions cannot detect abnormalities such as roll die wear or poor rolling.

[0007] The present invention has been made in view of the above circumstances, and its object is to quickly discover the occurrence of abnormalities such as wear of roll dies and processing defects of workpieces. [Means for solving the problem]

[0008] One aspect of a rolling processing system devised to solve the above-mentioned problems is characterized by comprising a rolling device that rolls a thread by clamping a workpiece by changing the relative distance between a pair of rotationally driven roll dies, an AE sensor that is arranged on a holding member that holds the rotation axis of one of the pair of roll dies or on a mounting base to which the holding member is attached and measures the acoustic emission of the roll die, a calculation means that calculates a specific value corresponding to the amount of deformation of the workpiece caused by the rolling device based on the measurement results of the AE sensor, and a detection means that detects the occurrence of an abnormality based on the specific value calculated by the calculation means.

[0009] According to this rolling system, a specific value corresponding to the deformation of the workpiece due to the rolling process is calculated based on the result of measuring the acoustic emission of the roll die during rolling, and an abnormality in the process is detected based on this specific value. Therefore, an abnormality in the rolling process can be quickly discovered, and it is possible to prevent the continuous production of defective products.

[0010] In the rolling processing system of the above aspect, it is desirable to provide a post-processing measurement means for measuring the diameter of the workpiece after processing by the rolling device, and the detection means for detecting the occurrence of an abnormality based on the specific value calculated by the calculation means and the measurement result by the post-processing measurement means.

[0011] For example, if the measurement results from the post-processing measuring means do not change significantly during operation of the rolling device, i.e., the amount of workpiece processing does not change significantly, but the specific value calculated based on the measurement results from the AE sensor changes significantly, it is possible that a large amount of energy is being lost as heat without being used in the rolling process. In such cases, the roll dies may be worn. Therefore, with this rolling system, it is possible to quickly detect wear in the roll dies. It is also possible to prevent defective products from being produced due to worn roll dies.

[0012] Furthermore, in the rolling processing system of the above aspect, it is desirable to provide a pre-processing measuring means for measuring the diameter of the workpiece before processing by the rolling device, and the detection means detects the occurrence of an abnormality based on the actual processing amount calculated based on the measurement results by the pre-processing measuring means and the measurement results by the post-processing measuring means, and on the specific value calculated by the calculation means.

[0013] According to this aspect of the rolling processing system, since it is equipped with not only a post-processing measuring means but also a pre-processing measuring means, the actual processing amount can be accurately measured by comparing the dimensions of the workpiece before and after processing, which makes it possible to more accurately discover wear of the roll dies and prevent the production of defective products.

[0014] In addition, in the rolling processing system of the above aspect, it is desirable that the pair of roll dies include a movable roll die that is capable of linear movement and a fixed roll die that is not capable of linear movement, and that the AE sensor is arranged on the holding member or the mounting base portion on the fixed roll die side.

[0015] According to this embodiment of the rolling processing system, the AE sensor is arranged on the side of the fixed roll die, so that it is possible to measure the acoustic emissions generated by the rolling processing in a manner that is less affected by operations other than the rolling processing, compared to a configuration in which the AE sensor is arranged on the side of the movable roll die.

[0016] In addition, one aspect of a method for monitoring abnormalities in a rolling device that has been devised to solve the above-mentioned problems is a method for monitoring abnormalities in a rolling device that rolls threads by clamping a workpiece by changing the relative distance between a pair of rotationally driven roll dies, characterized in that a specific value corresponding to the amount of deformation of the workpiece by the rolling device is calculated based on the measurement results of an AE sensor that is arranged on a holding member that holds the rotation axis of one of the pair of roll dies or on a mounting base to which the holding member is attached and measures the acoustic emission of the roll die, and the occurrence of an abnormality is detected based on the specific value.

[0017] According to the method for monitoring abnormalities in a rolling device of this aspect, a specific value corresponding to the deformation of the workpiece due to the rolling process is calculated based on the results of measuring the acoustic emission of the roll dies during rolling, and an abnormality in the process is detected based on this specific value. Therefore, an abnormality in the rolling process can be detected accurately and quickly. [Effects of the Invention]

[0018] The technology disclosed in this specification realizes a technology for quickly detecting the occurrence of abnormalities such as wear of roll dies and processing defects in workpieces. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a plan view schematically showing a rolling device in a rolling processing system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic front view showing a roll die and its surrounding configuration provided in the rolling device. [Figure 3] 1 is a block diagram showing an outline of a rolling system according to a first embodiment. [Figure 4] FIG. 10 is a diagram illustrating parameters that indicate the characteristics of an AE wave. [Figure 5]This is a graph showing the change in AE energy Veng over time during one processing period of the rolling device (the period during which one screw is manufactured), and also shows the results of an experiment in which the push-in amount D of the movable roll die against the workpiece (workpiece) was 2.16 mm, 1.76 mm, 1.36 mm, and no workpiece (No proc.). [Figure 6] 1 is a graph showing the change in the average value Vave eng of the AE energy Veng during one processing period (the period during which one screw is manufactured) in the production of 16,000 screws, and the change in the measured value of the outer diameter of the processed screws. [Figure 7] 7 is a graph showing the change in AE energy Veng over time during one processing period (the period for manufacturing one screw) for the production of the 4500th, 5100th, and 5700th screws in the experiment whose results are shown in FIG. [Figure 8] 4 is a flowchart schematically showing an abnormality monitoring process performed by a control unit in the rolling system according to the first embodiment. [Figure 9] 1 is a graph showing the change in AE energy Veng over time during one processing period (the period for manufacturing one screw) when rolling is performed normally and when an abnormality occurs. [Figure 10] 10 is a flowchart schematically showing an abnormality monitoring process according to the second embodiment. [Figure 11] FIG. 10 is a block diagram showing an outline of a rolling system according to a third embodiment. [Figure 12] 10 is a flowchart schematically showing an abnormality monitoring process according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1. First embodiment A rolling system TS according to a first embodiment of the present invention will be described below with reference to the drawings. First, a rolling device 10 included in the rolling system TS will be described with reference to Figs. 1 and 2. In the following description, the up-down and left-right directions of each part of the rolling device 10 will be described as being the up-down and left-right directions as seen from a person facing the rolling device 10. In addition, the front direction of each part of the rolling device 10 will be described as the direction approaching the person facing the rolling device 10 (the side on which roll dies 14L and 14R, described below, are arranged), and the rear direction of each part of the rolling device 10 will be described as the direction away from the person facing the rolling device 10 (the side on which gear boxes 17L and 17R, described below, are arranged).

[0021] Fig. 1 is a plan view showing a rolling device 10. As shown in Fig. 1, the rolling device 10 includes a left headstock 12L and a right headstock 12R, which are disposed opposite each other on the left and right sides of a fixed base (not shown). The left headstock 12L is fixed and cannot move, while the right headstock 12R is disposed so as to be movable horizontally in the left-right direction. It is sufficient that the left headstock 12L and the right headstock 12R can move forward and backward relative to each other (moving closer and further away), and both may be configured to be movable.

[0022] The left headstock 12L has a left roll die 14L rotatably disposed about a rotation axis 15L, and the right headstock 12R has a right roll die 14R rotatably disposed about a rotation axis 15R. The left roll die 14L is also referred to as a fixed roll die 14L, and the right roll die is also referred to as a movable roll die 14R. The left roll die 14L (fixed roll die 14L) and the right roll die 14R (movable roll die 14R) are sometimes referred to as roll dies 14.

[0023] The rotating shaft 15L of the left rolling die 14L is connected to the output shaft of the first servo motor 20 via a power transmission mechanism including a coupling 16L and a gearbox 17L. As a result, when the first servo motor 20 is rotated in a predetermined direction, the left rolling die 14L rotates counterclockwise as viewed from the front (see FIG. 2). The rotation speed of the left rolling die 14L is feedback-controlled by a control unit 80 (described below) that receives input from an encoder built into the first servo motor 20. Similarly, the rotating shaft 15R of the right rolling die 14R is connected to the output shaft of the second servo motor 22 via a power transmission mechanism including a coupling 16R and a gearbox 17R. As a result, when the second servo motor 22 is rotated in a predetermined direction, the right rolling die 14R rotates counterclockwise as viewed from the front (see FIG. 2). The rotation speed of the right rolling die 14R is feedback-controlled by a control unit 80 (described below) that receives input from an encoder built into the second servo motor 22.

[0024] Furthermore, bearings 24a and 24b are attached to the rotary shaft 15L of the left rolling die 14L on the front and rear sides of the left rolling die 14L. The rotary shaft 15L is rotatably supported by the left headstock 12L via the bearings 24a and 24b. As shown in FIG. 2, the front bearing 24a is fitted into a bracket (bearing block) 30L, and the base end of the bracket 30L (the left end in FIG. 2) is cantilevered onto a mounting base 32L that is provided vertically on the left headstock 12L. The bracket 30L is detachable from the left headstock 12L, and the left rolling die 14L can be replaced by removing the bracket 30L from the left headstock 12L.

[0025] Similarly, bearings 25a and 25b (see FIG. 1) are attached to the rotary shaft 15R of the right rolling die 14R on the front and rear sides of the right rolling die 14R. The rotary shaft 15R is rotatably supported by the right headstock 12R via the bearings 25a and 25b. As shown in FIG. 2, the front bearing 25a is fitted into a bracket (bearing block) 30R, and the base end (the right end in FIG. 2) of the bracket 30R is cantilevered onto a mounting base 32R installed vertically on the right headstock 12R. The bracket 30R is detachable from the right headstock 12R, and the right rolling die 14R can be replaced by removing the bracket 30R from the right headstock 12R. The brackets 30R and 30L are examples of retaining members.

[0026] As shown in FIG. 1 , the rolling device 10 includes a mounting table 34 between the left headstock 12L and the right headstock 12R, the mounting table 34 having a rest 35 on which a workpiece W (workpiece W) is placed. A ball screw 40 is attached to the right headstock 12R, and the ball screw 40 is connected to the output shaft of a third servo motor 42 via a power transmission mechanism, such as a gearbox 43 and a coupling 44. The front and rear of the right headstock 12R are fitted into two horizontal guides 46a and 46b provided along the left-right direction. The horizontal guides 46a and 46b guide the left-right movement of the right headstock 12R. When the third servo motor 42 is driven to rotate in a first direction (e.g., clockwise), the ball screw 40 rotates in the first direction (e.g., clockwise), and the right headstock 12R moves leftward along the left-right direction. This reduces the distance between the left roll die 14L and the right roll die 14R, allowing the workpiece W to be clamped and pressed between the left roll die 14L and the right roll die 14R to roll the threads, as shown in Figure 2.

[0027] Furthermore, when the third servo motor 42 is driven to rotate in a second direction (e.g., counterclockwise) opposite to the first direction, the ball screw 40 rotates in the second direction (e.g., counterclockwise), and the right headstock 12R moves to the right along the left-right direction. This increases the distance between the left roll die 14L and the right roll die 14R, allowing the machined workpiece (screw) to be removed and the next workpiece W to be set between the left roll die 14L and the right roll die 14R. The amount of depression and movement speed of the right roll die 14R driven by the third servo motor 42 are feedback-controlled by a control unit 80 (described below) that receives input from a displacement sensor such as a linear encoder and input from an encoder built into the third servo motor 42.

[0028] In this embodiment, a rolling device that uses a servo motor and a ball screw to control the amount of depression of the movable roll die 14R is used. However, a known hydraulic device (a device that includes a hydraulic cylinder, hydraulic piping, a servo pump, etc., and controls the amount of movement of the hydraulic cylinder by hydraulic control) may also be used to control the amount of depression of the roll die. Furthermore, FIG. 1 is merely a schematic diagram of the configuration of the rolling device 10, and does not accurately depict the shapes of each part of the rolling device 10, such as the left headstock 12L and the right headstock 12R, or the distance between the left roll die 14L and the workpiece W. In reality, as shown in FIG. 2, the right roll die 14R attached to the movable right headstock 12R is shaped and positioned so that the workpiece W can be clamped by moving the left roll die 14L attached to the fixed left headstock 12L closer to the right headstock 12R.

[0029] 2, an AE sensor 50 is attached to the upper surface of the mounting base 32L of the fixed left headstock 12L. More specifically, the AE sensor 50 is attached to a position on the upper surface of the mounting base 32L near the bracket 30L (a position near the bracket 30L in both the left-right direction and the front-rear direction).

[0030] The AE sensor 50 detects acoustic emissions (hereinafter also referred to simply as "AE") generated in the roll die 14 during rolling. By arranging the AE sensor 50 on the mounting base 32L on the side of the left roll die 14L (fixed roll die 14L) rather than on the mounting base 32R on the side of the right roll die 14R (movable roll die 14R) that can move linearly in the left-right direction, it is possible to detect AE with little influence from operations other than those during processing (such as rotation or movement of the roll die 14 when the workpiece W and the roll die 14 are not in contact). Furthermore, by arranging the AE sensor 50 on the mounting base 32L rather than on the bracket 30L, it is possible to replace the roll die 14 without removing the AE sensor 50.

[0031] Here, AE is a phenomenon in which, when a solid body is deformed or destroyed, the accumulated strain energy is released as high-frequency elastic waves of several tens of kilohertz to several megahertz. These elastic waves are called AE waves. The AE sensor 50 has a piezoelectric element, and converts the AE waves propagating from the roll die 14 to the mounting base portion 32L into an electrical signal by the piezoelectric effect and outputs the signal. In this embodiment, PZT (lead zirconate titanate) is used as the piezoelectric element of the AE sensor 50. The electrical signal corresponding to the AE waves detected by the AE sensor 50 is input to an AE measurement device 55 (FIG. 3), which will be described later.

[0032] Next, the configuration of the rolling system TS of this embodiment will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an outline of the rolling system TS. As shown in Fig. 3, the rolling system TS includes, in addition to the rolling device 10 and AE sensor 50 described above, an AE measurement device 55, a distance sensor 60 for measuring the thread diameter after machining (an example of a post-machining measurement means), a post-machining thread diameter measurement device 65, a control unit 80, and a display device 87.

[0033] The AE sensor 50 attached to the rolling device 10 is connected to an AE measuring device 55, which receives an electric signal (voltage signal) corresponding to the AE wave detected by the AE sensor 50. This voltage signal is called an AE signal. The AE measuring device 55 includes an amplifier, a BPF (band pass filter), etc. Note that an AE measuring device with a different internal circuit configuration may be used. The AE measuring device 55 uses the BPF to remove unnecessary frequencies (low frequency components (noise due to mechanical factors) resulting from the operation of the rolling device 10, not processing, and high frequency components (noise due to electrical factors) generated in various control circuits) from the voltage signal (AE signal) received from the AE sensor 50, and calculates multiple parameters that indicate the characteristics of the AE wave from the AE signal after noise removal, etc. The parameters that indicate the characteristics of the AE wave include the maximum amplitude V max , rise time 91, duration 93, AE energy V eng etc. are included.

[0034] 4 is a diagram for explaining parameters (AE parameters) that indicate the characteristics of the AE wave, and is a diagram that schematically shows an AE signal that has been subjected to processing such as noise removal by the AE measuring device 55. max is the maximum amplitude value in the sampling interval. The amplitude value is the voltage from the center to the displacement converted into decibels. The voltage value itself may be used as the amplitude value. The rise time 91 is the time from when the amplitude exceeds a preset threshold 92 to when the maximum amplitude V max The AE measurement device 55 allows the operator to set a threshold value 92 as desired, and the threshold value 92 is set to an appropriate value in order to remove electrical noise. The duration 93 is the time (unit: msec) from when an amplitude exceeding the threshold value 92 is observed until the amplitude exceeding the threshold value 92 is no longer observed. The AE energy V eng is the value (unit: dBs) obtained by integrating the square root of the amplitude over time over the sampling interval. In this embodiment, the AE energy V eng is calculated by the following formula:

[0035]

number

[0036] In Equation 1, "V eng (n)” is the AE energy, “f(t)” is the amplitude of the AE signal, “t” is the time when the amplitude value was acquired, “T s」 is the sampling period, and "n" is the number of samplings (a value indicating which sampling interval it is, a sampling interval number). The integral range in Equation 1, "(n-1)T s " to "nT s " represents one sampling interval (from the start time to the end time of one sampling interval). eng "(n)" is the time integral of the square root of the amplitude over one sampling interval, and is a value that represents the magnitude of the AE in that sampling interval. The length of one sampling interval (sampling period) is set appropriately within the range of approximately 1 msec to 10 msec.

[0037] As shown in FIG. 3, the AE measurement device 55 is connected to the control unit 80. The parameters calculated by the AE measurement device 55 (maximum amplitude V max , rise time 91, duration 93, AE energy V eng The rolling processing system TS of this embodiment is configured to input the AE energy V eng (n) is used to detect abnormalities in the rolling device 10. This will be described later.

[0038] Furthermore, on a screw production line including the rolling device 10, a distance sensor 60 for measuring the outer diameter of a screw machined by the rolling device 10 is arranged downstream of the rolling device 10. The outer diameter of a screw machined by the rolling device 10 (machined workpiece) is measured by the distance sensor 60 for measuring the outer diameter of the screw.

[0039] As shown in Fig. 3, the after-machining thread diameter measurement distance sensor 60 is connected to an after-machining thread diameter measurement device 65, to which a voltage signal corresponding to the dimension of the thread outer diameter detected by the after-machining thread diameter measurement distance sensor 60 is input. The after-machining thread diameter measurement device 65 is configured to include an amplifier, an analog-to-digital conversion circuit (A / D converter), etc., and converts the input analog voltage value to a digital value and outputs it to a control unit 80 connected to the after-machining thread diameter measurement device 65. Note that in this embodiment, the after-machining thread diameter measurement distance sensor 60 and the after-machining thread diameter measurement device 65 are configured to output a digital value representing the difference between the outer diameter of the machined thread and a predetermined reference outer diameter to the control unit 80. The digital value output to the control unit 80 is an example of information about the outer diameter of the machined thread.

[0040] In addition, the outer diameter of the thread after machining may be measured using a measuring means other than the distance sensor 60 for measuring the thread diameter after machining and the device 65 for measuring the thread diameter after machining, such as a known laser microgauge, as long as the outer diameter of the thread can be measured.

[0041] The control unit 80 includes multiple control devices, such as a PLC (Programmable Logic Controller) and a PC (Personal Computer), which are connected to each other for communication. The control unit 80 controls the operation of the rolling apparatus 10 based on input information from the AE measurement device 55 and the after-machining thread diameter measurement device 65, and displays images showing the operating status of the rolling apparatus 10 (the status of the rolling process) on a display device 87, such as an LCD display. The PLC of the control unit 80 includes a device that controls the entire rolling apparatus 10. Note that information from the after-machining thread diameter measurement device 65 may be input to the control unit 80 via the AE measurement device 55. The PC of the control unit 80 includes a CPU, ROM, RAM, etc., and is capable of executing various programs (including the abnormality monitoring process described below) stored in the ROM. The control unit 80 executes the abnormality monitoring process described below, enabling abnormalities in the rolling apparatus 10 to be detected. Input devices, such as a keyboard and mouse (not shown), are connected to the PC, allowing an operator to input instructions.

[0042] The control unit 80 only needs to be capable of outputting the operating status (rolling processing status) of the rolling device 10 to an output device such as a display device 87 based on the measurement results of the AE sensor 50 and the measurement results of the distance sensor 60 for measuring the thread diameter after processing, and of controlling the operation of the rolling device 10, and the type and number of control devices constituting the control unit 80 can be changed as appropriate.

[0043] Here, the control unit 80 includes a calculation unit 81, an abnormality determination unit 82, an abnormality processing unit 83, and a storage unit 84. The storage unit 84 is configured with a RAM of a PC or the like, and stores various parameters (maximum amplitude V max , rise time 91, duration 93, AE energy V eng The control unit 80 stores information on the outer diameter of the thread after machining input from the thread diameter measuring device 65 after machining, and stores the results of calculations by the CPU.

[0044] The calculation unit 81 (an example of a calculation means) calculates the AE energy V stored in the storage unit 84. eng Based on this information, the AE energy V during the period of manufacturing one screw (hereinafter referred to as "one processing period" or "one processing cycle") is calculated. eng In this embodiment, the average AE energy in one processing cycle (hereinafter also simply referred to as "average AE energy") is calculated by the following formula.

[0045]

number

[0046]

number

[0047] The range of cumulative addition in Equation 2, from "(q-1)N" to "qN", represents one machining process (from the first sampling section number to the last sampling section number of one machining process).ave eng (q)" is the total AE energy V included in one processing process (one processing cycle) during that period. eng The values ​​of are cumulatively added, and the sum is used as the AE energy V included in that period. eng This is a value that represents the average AE energy in one processing cycle. One processing cycle (one processing process) generally lasts for about 1 to 10 seconds.

[0048] The average AE energy V calculated by the calculation unit 81 ave eng is stored in the storage unit 84 in association with the information on the outer diameter of the thread after machining input from the post-machining thread diameter measuring device 65 to the control unit 80 for each machining cycle.

[0049] The abnormality determination unit 82 (one example of a detection means) detects the average AE energy V calculated by the calculation unit 81. ave eng Based on this, it is determined whether or not an abnormality has occurred in the rolling process. Furthermore, when the abnormality determination unit 82 determines that an abnormality has occurred in the rolling process, the abnormality processing unit 83 displays an image on the display device 87 to notify the occurrence of the abnormality, or stops the rolling device 10. The calculation unit 81, the abnormality determination unit 82, and the abnormality processing unit 83 are composed of a CPU of a PC that executes the abnormality monitoring process (FIG. 8) described below. Note that the notification of the occurrence of an abnormality does not have to be by displaying an image on the display device 87, but may also be by lighting up a warning lamp connected to the control unit 80 or outputting a warning sound from a speaker, etc.

[0050] Here, it has not been clear in the past how the state of the rolling process is reflected in the measurement results of the acoustic emissions generated in the roll die 14 during the rolling process. The inventors of the present application have found through Experiment 1 described below that the difference in the amount of depression of the movable roll die 14R (in other words, the difference in the amount of plastic deformation of the workpiece W) affects the AE energy V during the process. eng In addition, in Experiment 2 described below, we found that the average AE energy V aveeng It was found that there is a correlation between the measured outer diameter of the machined screw and the actual value of the outer diameter of the machined screw. Below, Experiment 1 will be explained in detail with reference to Fig. 5, and Experiment 2 will be explained in detail with reference to Figs. 6 and 7.

[0051] First, Experiment 1 will be described. In Experiment 1, the rolling device 10 used was the "R17NC-II" manufactured by Tsugami Corporation. The AE sensor 50 was attached to the top surface of the bracket (bearing block) 30L, not to the top surface of the mounting base 32L on the fixed roll die 14L side shown in Figure 2. The workpiece W (unmachined workpiece for testing) was made of iron-based metal with a diameter of Φ19 mm and a length (axial length) of 55 mm. One rolling process (cycle time) was set to 4 seconds. Under these conditions, the AE energy V in one process was calculated for the cases where the push-in amount D of the movable roll die 14R was set to 1.36 mm, 1.76 mm, and 2.16 mm. eng In addition, when the rolling device 10 was operated without setting an unmachined workpiece (denoted as "No. proc"), in other words, when the push-in amount D was set to 0 mm, the AE energy V in one machining process was also observed. eng The results are shown in Figure 5.

[0052] Figure 5 shows the relationship between the elapsed time and the AE energy V eng As shown in Fig. 5, the difference in the push-in amount D has a significant effect on the AE energy V eng Specifically, the larger the indentation depth D of the roll die 14R, the greater the AE energy V eng In particular, when the push-in distance D is set to 2.16 mm, the peak value of the AE energy V eng The peak value of 7 In addition, when the push-in distance D is set to 1.76 mm, the AE energy V eng The peak value of 7 dBs but not exceeding 2.5 × 10 7In addition, when comparing the case where the push-in amount D is 2.16 mm with the case where the push-in amount D is 1.76 mm, the AE energy V eng The timing at which the value of V starts to fall from the peak value (fall timing) is slow, and the AE energy V eng The value is 2.5×10 7 This is thought to be because the larger the plunge depth D of the movable roll die 14R, the larger the amount of plastic deformation of the unprocessed workpiece, and the more AE waves were generated. Therefore, the AE energy V eng It was found that the state of the rolling process (the amount of plastic deformation of the workpiece W) can be monitored by observing the peak value and the timing of the fall in the transition.

[0053] Next, Experiment 2 will be described. In Experiment 2, the AE sensor 50 was attached to the upper surface of the attachment base portion 32L on the fixed roll die 14L side, as shown in FIG. 2. The workpiece W used was made of iron-based metal with a diameter of Φ10 mm and a length (axial length) of 30 mm. One rolling process (cycle time) was set to 3 seconds. Under these conditions, threads were rolled on 16,000 workpieces W (16,000 trials), and the average AE energy V ave eng The relationship between the measured value of the outer diameter of the machined screw and the measured value of the outer diameter of the machined screw was observed. The results are shown in Figure 6.

[0054] Figure 6 shows the average AE energy V ave eng 1 is a graph showing the measured values ​​of the outer diameter of the machined thread (digital values ​​output by the post-machining thread diameter measuring device 65) in the trial order (the order in which the machining process is carried out). The measured value of the outer diameter of the machined thread (Diameter Sensor Value) is a value corresponding to the difference between the outer diameter of the machined thread and a predetermined reference outer diameter (called the outer diameter difference), and the larger the value, the larger the outer diameter of the machined thread. The value "2300" corresponds to an outer diameter difference of 0.8625 mm, and the value "2200" corresponds to an outer diameter difference of 0.825 mm. The average AE energy V aveeng In order to reduce errors due to variability between trials and make it easier to confirm trends, a moving average filter (low-pass filter using the moving average method) of 200 samples (200 trials) was applied.

[0055] As shown in Figure 6, the average AE energy V ave eng The transition trend of the thread diameter (Diameter Sensor Value) coincides with the trend of the measured value of the outer diameter of the machined screw. In other words, this experiment shows that the average AE energy V ave eng It was found that there is a correlation between the average AE energy V ave eng It was found that by looking at this, it is possible to monitor the outer diameter of the thread after machining.

[0056] Next, in the experimental results shown in Fig. 6, the data in the section from the 4500th trial to the 5700th trial (the hatched section in Fig. 6) where a particularly strong correlation is observed was used to determine the AE energy V eng We investigated whether differences in the outer diameter of the machined screws would appear in the value of . Figure 7 shows the relationship between the elapsed time and the AE energy V in one machining process for the 4500th, 5100th, and 5700th trials in Experiment 2. eng As shown in Fig. 7, the AE energy V eng Specifically, the outer diameter of the machined thread becomes smaller in the order of 4500th trial → 5100th trial → 5700th trial (see Fig. 6), but Fig. 7 shows that the AE energy V of the 4500th trial, which produced the largest outer diameter of the machined thread, was engThe value of V remained larger than the other two, and the AE energy V of the 5700th trial, which had the smallest outer diameter of the machined screw, eng The value of V remained smaller than the other two, and the AE energy V of the 5100th trial, which is the value where the outer diameter of the machined screw is between the other two, eng The value of V is roughly between the other two. Therefore, the AE energy V during the rolling period from 0.5 seconds to 1.8 seconds in one processing cycle eng Due to the difference in the value of , the average AE energy V ave eng It was found that differences were apparent.

[0057] From the above experiment 2, the average AE energy V ave eng It was found that it is possible to monitor the outer diameter of the machined thread by observing the average AE energy V ave eng Instead, it can be said that it is possible to monitor the outer diameter of the machined thread and the amount of plastic deformation of the workpiece W by looking at the average AE energy for just the rolling period in one processing cycle (the period from 0.5 seconds to 1.8 seconds in Figure 7).

[0058] The rolling system TS of the first embodiment is configured based on the results of the above-mentioned Experiments 1 and 2. In this rolling system TS, the CPU of the PC included in the control unit 80 executes the abnormality monitoring process shown in FIG. 8 to detect abnormalities. This abnormality monitoring process is a process that is executed constantly while the rolling device 10 is in operation. As shown in FIG. 8, in the abnormality monitoring process (S100), the control unit 80 receives parameters indicating the characteristics of the AE wave (maximum amplitude V max , rise time 91, duration 93, AE energy V engThe control unit 80 then acquires the machining data (e.g., data on the machining of one screw) and stores it in the storage unit 84 (S11). Next, the control unit 80 determines whether one machining cycle (machining of one screw) has ended (S12). If one machining cycle has not ended (NO in S12), the process returns to step S11. In other words, the control unit 80 repeatedly performs the process of S11 until one machining cycle has ended.

[0059] When it is determined in step S12 that one processing cycle has ended, the control unit 80 calculates the average AE energy V ave eng Next, the control unit 80 calculates the average AE energy V calculated in step S13. ave eng is within a preset normal range (S14). The normal range values ​​(upper and lower limits) are set by an operator to an optimum range based on past experience, depending on the outer diameter and dimensional tolerance of the screw to be manufactured. Before mass production of screws begins using the rolling device 10, a trial run is carried out to set the normal range, and the average AE energy V when good screws are manufactured in this trial run is calculated. ave eng The control unit 80 may be configured to automatically set the upper and lower limits of the normal range from the calculated value.

[0060] As mentioned above, the average AE energy V ave eng The value of is correlated with the outer diameter of the machined screw (the amount of plastic deformation of the workpiece W). Therefore, the average AE energy V calculated in step S13 ave eng If the value is outside the normal range, there is a high possibility that an abnormality has occurred, such as a defective screw being manufactured or the roll die 14 being worn.

[0061] Here, the AE energy V in one processing cycle when rolling is performed normally is eng The transition of AE energy V in one processing cycle when abnormal rolling is performed. engThe transition of AE energy V in one processing cycle when rolling was performed under the same conditions as in Experiment 2 will be explained based on Fig. 9. eng 1 is a graph showing the transition of the rolling speed for three cases where the rolling process was performed normally (shown as "Normal 1," "Normal 2," and "Normal 3") and one case where an abnormality occurred (shown as "Abnormal").

[0062] As shown in Fig. 9, in all three cases where rolling was performed normally (shown as "Normal 1," "Normal 2," and "Normal 3"), the AE energy V during the rolling period from 0.5 seconds to 1.8 seconds in one processing cycle was eng The value of is 5×10 7 The average AE energy V calculated in these normal cases 1 to 3 is approximately 100 dB. ave eng is a value that falls within the "normal range" seen in step S14 of FIG.

[0063] In contrast, when abnormal rolling processing is performed (the case shown as "abnormal"), as shown in Figure 9, the rolling time from 0.5 seconds to 1.8 seconds in one processing cycle (at about 1.4 seconds) is 1.2 × 10 8 The AE energy V is about 1 / 4 of a sigma, which is not measured under normal circumstances. eng Therefore, the average AE energy V calculated in the case of an abnormality ave eng becomes a value that exceeds the "normal range" seen in step S14 of Figure 8. In such a case, an abnormality has occurred, such as a defective screw that does not fall within the dimensional tolerance range being manufactured, or wear occurring in the roll die 14.

[0064] Therefore, in the rolling processing system TS of this embodiment, the control unit 80 calculates the average AE energy V ave eng(an example of a "specific value") is determined to be within a normal range, and if it is determined to be not within the normal range (NO in S14), the occurrence of an abnormality is notified (S15) and the operation of the rolling device 10 is stopped (S16). To notify the abnormality (step S15), the control unit 80 displays an abnormality notification image (for example, an image including the words "abnormality occurred") in a relatively large size on the display unit of the display device 87. Meanwhile, in step S14, the average AE energy V ave eng If it is determined that the average AE energy V is within the normal range (YES in S14), the process returns to step S11. ave eng As long as the value is within the normal range, the processes shown in steps S11 to S14 are repeated.

[0065] In this embodiment, the control unit 80 is configured to execute processing upon detection of an abnormality, such as reporting the abnormality (S15) and stopping the rolling device 10 (S16), but it may also be configured so that another computer (for example, a master computer that collectively manages multiple rolling devices in a screw manufacturing factory) that receives a notification of the occurrence of an abnormality from the control unit 80 executes processing upon detection of an abnormality, such as reporting the abnormality and stopping the rolling device 10. In other words, the control unit 80 may not be configured to include the abnormality processing unit 83.

[0066] In this form, AE energy V eng to the average AE energy V ave eng Calculate the average AE energy V ave eng The structure is such that abnormalities are detected by determining whether the average AE energy V ave eng Without calculating the AE energy V eng The value of AE energy V in one processing cycle when rolling is performed normally. eng In this case, the AE energy V engis an example of a "specific value", and the AE measuring device 55 is an example of a "calculating means". eng Rather than determining whether there is an abnormality based on the value of the average AE energy V ave eng It is expected that the effect of noise will be reduced and an accurate abnormality judgment will be possible by determining whether an abnormality is present or not based on the average AE energy V ave eng Alternatively, an abnormality may be detected by calculating the average AE energy for only the rolling period in one processing cycle (the period from 0.5 seconds to 1.8 seconds in FIG. 7, in other words, the period from when the roll die 14 starts to contact the workpiece W until the roll die 14 is no longer in contact with the workpiece W), and determining whether this calculated value is within a normal range. In this case, the average AE energy for only the rolling period is an example of the "specific value."

[0067] The rolling processing system TS of the first embodiment described above in detail includes a rolling device 10 that rolls a thread by sandwiching a workpiece W between two roll dies (a left roll die 14L and a right roll die 14R) by changing the relative distance between the pair of roll dies that are driven to rotate, an AE sensor 50 that is attached to the attachment base part 32L on the side of the left roll die 14L and that measures the acoustic emissions of the roll dies 14, and an average AE energy V that corresponds to the amount of deformation of the workpiece W by the rolling device 10 based on the measurement results of the AE sensor 50. ave eng 3 and step S13 shown in FIG. 8), and the average AE energy V calculated by the calculation unit 81. ave eng and an abnormality determination unit 82 (see step S14 shown in FIGS. 3 and 8) that detects the occurrence of an abnormality based on the above.

[0068] According to the rolling processing system TS of this embodiment, based on the results of measuring the acoustic emission of the roll die 14 during rolling, the average AE energy V ave engCalculate the average AE energy V ave eng In other words, in this embodiment, the detection of a machining abnormality is based on the cumulative energy (AE energy V eng ) and then calculate this AE energy V eng Average AE energy V ave eng ) and calculate the average AE energy V ave eng Therefore, it is possible to quickly discover abnormalities in the rolling process that are difficult to detect based on changes in the amplitude of AE waves, and to prevent the continued production of defective products.

[0069] In addition, in the rolling processing system TS of this embodiment, the pair of roll dies 14L, 14R includes a movable roll die 14R that can move linearly along the left-right direction and a fixed roll die 14L that cannot move linearly, and the AE sensor 50 is arranged on the mounting base portion 32L on the fixed roll die 14L side.

[0070] Therefore, compared to a configuration in which the AE sensor 50 is disposed on the side of the movable roll die 14R, it is possible to measure the acoustic emissions generated by the rolling process in a manner that is less affected by operations other than those during the process.

[0071] The first embodiment also includes a method for monitoring an abnormality in a rolling device 10 that rolls a thread by sandwiching a workpiece W between two roll dies (a left roll die 14L and a right roll die 14R) by changing the relative distance between the pair of roll dies that are driven to rotate. The method includes a method for monitoring an abnormality in a rolling device 10 that rolls a thread by changing the relative distance between the pair of roll dies (a left roll die 14L and a right roll die 14R) that are driven to rotate, and the method includes a method for monitoring an abnormality in a rolling device 10 that rolls a thread by sandwiching a workpiece W between two roll dies (a left roll die 14L and a right roll die 14R). The method is mounted on the mounting base 32L on the left roll die 14L side and measures the acoustic emissions of the roll dies 14. The method includes a method for monitoring an abnormality in a rolling device 10 that rolls a thread by changing the relative distance between the pair of roll dies (a left roll die 14L and a right roll die 14R). ... ave eng Calculate the average AE energy V ave engAn anomaly monitoring method for detecting the occurrence of an anomaly based on the above is disclosed.

[0072] According to the abnormality monitoring method having this configuration, the average AE energy V that is correlated with the deformation amount of the workpiece W due to the rolling process is calculated based on the result of measuring the acoustic emission of the roll die 14 during rolling. ave eng Calculate the average AE energy V ave eng Therefore, it is possible to accurately and quickly detect abnormalities in the rolling process.

[0073] 2. Second embodiment Next, a rolling system according to a second embodiment will be described with reference to FIG. 10. In the description of the rolling system according to the second embodiment, the same components as those in the rolling system TS according to the first embodiment will be denoted by the same reference numerals and will not be described again. In the rolling system according to the second embodiment, the control unit 80 performs an abnormality monitoring process shown in FIG. 10. This is the difference from the first embodiment. In the abnormality monitoring process shown in FIG. 10, the average AE energy V ave eng The presence or absence of an abnormality is determined not only based on the value of , but also based on the outer diameter information of the machined thread calculated based on the measurement result of the distance sensor 60 for measuring the thread diameter after machining. As described in the explanation of the first embodiment, the control unit 80 acquires the outer diameter information of the machined thread. Note that the rolling system TS of the first embodiment does not determine the presence or absence of an abnormality based on the outer diameter information of the machined thread, and therefore may not be configured to include the distance sensor 60 for measuring the thread diameter after machining and the distance sensor 60 for measuring the thread diameter after machining and the distance sensor 60 for measuring the thread diameter after machining.

[0074] The abnormality monitoring process in the rolling system of the second embodiment (FIG. 10) differs from the abnormality monitoring process in the rolling system TS of the first embodiment (FIG. 8) mainly in the processes from step S24 onwards. The processes of steps S21 to S23 shown in FIG. 10 are the same as the processes of steps S11 to S13 shown in FIG.

[0075] As shown in FIG. 10, in the abnormality monitoring process according to the second embodiment, the control unit 80 that has performed the process of step S23 subsequently acquires information on the outer diameter of the thread after machining from the thread diameter measuring device 65 after machining, and calculates the average AE energy V ave eng The information is stored in the storage unit 84 in association with the fact that it is information on the same machining cycle as the information on the machining cycle (S24). Thereafter, the control unit 80 determines whether the outer diameter of the machined screw is within a predetermined normal range based on the information acquired in step S24 (S25). The values ​​of this normal range (upper and lower limits) are set by the operator according to the outer diameter and dimensional tolerance of the screw to be manufactured.

[0076] If it is determined in step S25 that the outer diameter of the machined screw is not within the normal range (NO in S25), a machining defect has occurred, so the control unit 80 notifies the occurrence of the machining defect (S26) and stops the operation of the rolling device 10 (S27). To notify the occurrence of the machining defect (step S26), the control unit 80 displays a machining defect notification image (for example, an image including the words "machining defect occurred") in a relatively large size on the display unit of the display device 87.

[0077] On the other hand, if it is determined in step S25 that the outer diameter of the thread after machining is within the normal range (YES in S25), the control unit 80 then ave eng In step S28, it is determined whether the average AE energy V ave eng is within the normal range (YES in S28), the process returns to step S21. In other words, the control unit 80 determines whether the outer diameter of the thread after machining is within the normal range and the average AE energy V ave eng As long as the value is within the normal range, the processes shown in steps S21 to S25 and S28 are repeated.

[0078] In contrast, in step S28, the average AE energy V ave engis not within the normal range (NO in S28), the roll die 14 may be worn, so the control unit 80 issues a warning that the roll die 14 may be worn (S29) and stops the operation of the rolling device 10 (S27). To report that the roll die 14 may be worn (step S29), the control unit 80 displays a wear warning image (for example, an image including the words "Die wear has occurred") in a relatively large size on the display unit of the display device 87.

[0079] In step S28, the average AE energy V ave eng The reason why it is considered that the roll die 14 may be worn when it is determined that is not within the normal range is as follows: as determined in step S25, even though the outer diameter of the thread after machining is within the normal range and has not changed significantly, the average AE energy V ave eng The fact that the value of the rolling die 14 has changed significantly beyond the normal range is thought to indicate that a large amount of energy is being lost as heat without being used in the rolling process, and this generation of heat is thought to be due to the use of worn roll dies 14.

[0080] The thread rolling system of the second embodiment described above includes a distance sensor 60 (an example of a post-processing measuring means) for measuring the outer diameter of the thread (the diameter of the workpiece after processing) processed by the thread rolling device 10, and the abnormality determination unit 82 of the control unit 80 determines the average AE energy V calculated by the calculation unit 81. ave eng Based on the measurement results (information on the outer diameter of the machined screw) of the post-machining thread diameter measurement distance sensor 60, the occurrence of an abnormality is detected (see steps S25 and S28 shown in FIGS. 3 and 10).

[0081] For example, during the operation of the rolling device 10, even if the measurement result by the distance sensor 60 for measuring the thread diameter after processing does not change significantly, that is, even if the processing amount of the workpiece W does not change significantly, the average AE energy V calculated based on the measurement result of the AE sensor 50 aveeng If there is a large change in the rolling speed, it is considered that a large amount of energy is being lost as heat without being used in the rolling process. In such a case, the roll die 14 may be worn. Therefore, the rolling system of this embodiment makes it possible to quickly detect wear of the roll die 14. It also makes it possible to prevent defective products from being produced by worn roll dies 14.

[0082] Furthermore, while continuing production with a worn roll die 14 may result in defective products, the rolling system of the second embodiment can quickly detect wear on the roll die 14, making it possible to continue using the roll die 14 until an abnormality occurs. This makes it possible to extend the useful life of the roll die 14 rather than replacing the roll die 14 periodically with a margin of error, thereby reducing the operating costs (screw manufacturing costs) of the rolling device 10. In other words, the rolling system of this embodiment makes it possible to determine the optimal replacement timing for the replacement span (useful life) of the roll die 14.

[0083] 3. Third embodiment Next, a rolling system TS3 of a third embodiment will be described with reference to Figures 11 and 12. In the description of the rolling system TS3 of the third embodiment, the same components as those of the rolling system TS of the first embodiment and the rolling system of the second embodiment will be denoted by the same reference numerals and will not be described again. As shown in Figure 11, the rolling system TS3 of the third embodiment is equipped with a distance sensor 70 for measuring the diameter of an unmachined workpiece (an example of a pre-machining measuring means) and an unmachined workpiece diameter measuring device 75, and the control unit 80 performs an abnormality monitoring process shown in Figure 12. This is the difference from the first and second embodiments.

[0084] In the thread rolling system TS3 of the third embodiment, a distance sensor 70 for measuring the diameter of an unmachined workpiece (workpiece W) before it is machined by the rolling device 10 is arranged upstream of the rolling device 10 on a screw production line including the rolling device 10. The diameter of the workpiece W (unmachined workpiece) before it is machined by the rolling device 10 is measured by the distance sensor 70 for measuring the diameter of the unmachined workpiece. The distance sensor 70 for measuring the diameter of an unmachined workpiece can suitably be the same as the distance sensor 60 for measuring the thread diameter after machining.

[0085] As shown in Figure 11, the unmachined work diameter measuring distance sensor 70 is connected to an unmachined work diameter measuring device 75, and a voltage signal corresponding to the diameter of the unmachined work detected by the unmachined work diameter measuring distance sensor 70 is input to the unmachined work diameter measuring device 75. The unmachined work diameter measuring device 75 is configured to include an amplifier, an analog-to-digital conversion circuit (A / D converter), etc., and converts the input analog voltage value into a digital value and outputs it to a control unit 80 connected to the unmachined work diameter measuring device 75. The unmachined work diameter measuring device 75 can suitably be the same as the post-machining thread diameter measuring device 65.

[0086] In the abnormality monitoring process (FIG. 12) in the rolling processing system TS3 of the third embodiment, the average AE energy V ave eng The presence or absence of an abnormality is determined not only based on the value of (a) but also based on the actual machining amount of the workpiece W calculated based on the measurement results of the distance sensor 60 for measuring the thread diameter after machining and the measurement results of the distance sensor 70 for measuring the diameter of the unmachined workpiece.

[0087] The abnormality monitoring process in the rolling system TS3 of the third embodiment (FIG. 12) differs from the abnormality monitoring process in the rolling system of the second embodiment (FIG. 10) mainly in the processes from step S35 onwards. The processes of steps S31 to S34 shown in FIG. 12 are the same as the processes of steps S21 to S24 shown in FIG.

[0088] 12, in the abnormality monitoring process according to the third embodiment, the control unit 80 that has performed the process of step S34 subsequently acquires diameter information of the unmachined workpiece from the unmachined workpiece diameter measuring device 75 (S35). Then, based on the diameter information of the unmachined workpiece acquired in step S35 and the outer diameter information of the machined thread acquired in step S34, it calculates the actual machining amount (difference in outer diameter) of the unmachined workpiece (workpiece W) and the average AE energy V calculated in step S33. ave eng The information is stored in the storage unit 84 in association with the information on the same machining cycle (S36).

[0089] Thereafter, the control unit 80 determines whether the actual machining amount is within a predetermined normal range based on the information on the actual machining amount calculated in step S36 (S37). The values ​​of this normal range (upper and lower limits) are set by the operator according to the outer diameter and dimensional tolerances of the screw to be manufactured and the diameter and dimensional tolerances of the unmachined workpiece.

[0090] If it is determined in step S37 that the actual processing amount is not within the normal range (NO in S37), a processing defect has occurred, and the control unit 80, as in the second embodiment, notifies the occurrence of a processing defect (S38) and stops the operation of the rolling device 10 (S39).

[0091] On the other hand, if it is determined in step S37 that the actual machining amount is within the normal range (YES in S37), the control unit 80 then ave eng In step S40, it is determined whether the average AE energy V ave eng is within the normal range (YES in S40), the process returns to step S31. In other words, the control unit 80 determines that the actual machining amount is within the normal range and the average AE energy V ave eng As long as is within the normal range, the processes shown in steps S31 to S37 and S40 are repeated.

[0092] On the other hand, in step S40, the average AE energy V ave eng If it is determined that the rolling die 14 is not within the normal range (NO in S40), as in the second embodiment, the roll die 14 may be worn, so the control unit 80 issues a warning that the roll die 14 may be worn (S41) and stops the operation of the rolling device 10 (S39).

[0093] In the above configuration, if an abnormality is detected in the abnormality monitoring process, a notification to that effect is issued and the rolling device 10 is stopped, but it is also possible to configure the device to only issue a notification or to only stop the rolling device 10. Furthermore, in the above configuration, if an abnormality is detected even once, the rolling device 10 is stopped, but it is also possible to configure the device to stop the rolling device 10 when an abnormality is detected a predetermined number of times (for example, five times). These modifications may be made in the first embodiment or the second embodiment described above.

[0094] As described above, the rolling processing system TS3 of the third embodiment is provided with the unmachined work diameter measurement distance sensor 70 that measures the diameter of the unmachined work before being machined by the rolling device 10 (the diameter of the workpiece before machining), and the abnormality determination unit 82 of the control unit 80 determines the actual machining amount calculated based on the measurement result of the unmachined work diameter measurement distance sensor 70 (information on the diameter of the unmachined work) and the measurement result of the post-machining thread diameter measurement distance sensor 60 (information on the outer diameter of the machined thread), and the average AE energy V calculated by the calculation unit 81. ave eng Based on this, occurrence of an abnormality is detected (see steps S34 to S37 and S40 shown in FIGS. 11 and 12).

[0095] According to the rolling processing system TS3 of this embodiment, since it is equipped with not only the distance sensor for measuring the thread diameter after processing 60 but also the distance sensor for measuring the diameter of the unprocessed workpiece 70, the actual processing amount can be correctly measured by comparing the diameter of the unprocessed workpiece with the outer diameter of the processed thread. Therefore, it becomes possible to discover wear of the roll die 14 and prevent the production of defective products more accurately than a configuration in which the processing amount of the workpiece W is determined only from the outer diameter of the processed thread.

[0096] The above describes the rolling processing systems of the first, second, and third embodiments, but the present invention is not limited to the above-mentioned embodiments and can be modified as appropriate within the scope of the gist of the present invention.

[0097] In the above-described embodiments, the AE sensor 50 is attached to the upper surface of the mounting base 32L on the side of the left rolling die 14L (fixed rolling die 14L), but it may also be attached to the upper surface of the mounting base 32R on the side of the right rolling die 14R (movable rolling die 14R). Also, the AE sensor 50 may be attached to the upper surface of the bracket 30L on the side of the left rolling die 14L (fixed rolling die 14L) or to the upper surface of the bracket 30R on the side of the right rolling die 14R (movable rolling die 14R).

[0098] In each of the above-described embodiments, the distance sensor 60 for measuring the thread diameter after machining is configured to measure the outer diameter of the machined thread, but the distance sensor 60 may be configured to measure a diameter other than the outer diameter, such as the radius, root diameter, or pitch diameter, as long as the value changes depending on the amount of plastic deformation of the workpiece W due to the rolling process. In this case, the measurement target of the distance sensor 70 for measuring the diameter of the unmachined workpiece may also be changed to the radius or the like in accordance with the measurement target of the distance sensor 60 for measuring the thread diameter after machining.

[0099] In each of the above-described embodiments, the calculation unit 81 (see FIG. 3) and the abnormality determination unit 82 are configured to be performed by a PC included in the control unit 80, but the control device that performs the calculation unit 81 and the control device that performs the abnormality determination unit 82 may be separate. Also, the control unit 80 may be configured to perform the functions of the AE measurement device 55 and the post-machining thread diameter measurement device 65. Also, the control unit 80 may be configured to perform the functions of the unmachined workpiece diameter measurement device 75 (see FIG. 11). [Explanation of symbols]

[0100] TS...Rolling processing system 10...Rolling device 14...Roll Dice 14L...Left side roll die (fixed roll die) 14R...Right side roll die (movable roll die) 15L...Rotating shaft 15R...Rotation axis 30L...Bracket (holding member) 30R...Bracket (retaining member) 32L...Mounting base 32R...Mounting base 50...AE sensor 60... Distance sensor for measuring thread diameter after machining (measurement means after machining) 70...Distance sensor for measuring the diameter of unmachined workpiece (pre-machining measurement means) 80...Control unit 81...Arithmetic section 82...Abnormality determination section W…Workpiece

Claims

1. a rolling device that rolls threads by sandwiching a workpiece between a pair of rotationally driven roll dies and changing the relative distance between the workpiece and the roll dies; an AE sensor that is disposed on a holding member that holds one of the rotation shafts of the pair of roll dies or on an attachment base portion to which the holding member is attached, and that measures acoustic emissions from the roll die; a calculation means for calculating a specific value corresponding to the deformation amount of the workpiece caused by the rolling device based on the measurement result of the AE sensor; a detection means for detecting the occurrence of an abnormality based on the specific value calculated by the calculation means.

2. The rolling processing system according to claim 1, a post-processing measuring means for measuring the diameter of the workpiece after processing by the rolling device; The rolling processing system is characterized in that the detection means detects the occurrence of an abnormality based on the specific value calculated by the calculation means and the measurement result by the post-processing measurement means.

3. The rolling processing system according to claim 2, a pre-processing measuring means for measuring the diameter of the workpiece before processing by the rolling device; A rolling processing system characterized in that the detection means detects the occurrence of an abnormality based on the actual processing amount calculated based on the measurement results by the pre-processing measuring means and the measurement results by the post-processing measuring means, and the specific value calculated by the calculation means.

4. The rolling processing system according to any one of claims 1 to 3, The pair of roll dies includes a movable roll die that is capable of linear movement and a fixed roll die that is not capable of linear movement, The rolling processing system is characterized in that the AE sensor is disposed on the holding member or the mounting base portion on the fixed roll die side.

5. 1. A method for monitoring an abnormality in a rolling device that rolls threads by sandwiching a workpiece between a pair of rotationally driven roll dies, the method comprising: A method for monitoring abnormalities in a rolling device, characterized in that a specific value corresponding to the amount of deformation of the workpiece caused by the rolling device is calculated based on the measurement results of an AE sensor that is arranged on a holding member that holds one of the rotation axes of the pair of roll dies or on a mounting base portion to which the holding member is attached and that measures the acoustic emissions of the roll die, and the occurrence of an abnormality is detected based on the specific value.

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