MANAGEMENT SYSTEM, METHOD FOR DETECTING A SPINDLE FAULT USING A MANAGEMENT DEVICE AND NON-VOID COMPUTER-READABLE MEDIUM

Abstract

Management system (30) comprising a network, a plurality of manufacturing cells (104) connected to the network, and a management device (100) connected to the network and managing the plurality of manufacturing cells (104), wherein the manufacturing cell (104) contains: a machine tool of the same type as a machine tool in another of the manufacturing cells; as well as a control device (22) that controls the machine tool, analyzes a vibration status of a spindle positioning shaft of the machine tool and sends a result of the analysis via the network, wherein, in the case that the machine tool is in a non-processing state, the control device sends over the network, as a result of the analysis, only a frequency spectrum intensity which has at least one predetermined value from frequency spectrum intensities obtained by performing a Fourier transform of a feedback signal of a spindle-positioning axial servomotor when the spindle of the machine tool rotates at the same rotational speed as a machine tool in another of the manufacturing cells, and the management device (100) contains: a communication unit (502) that receives the result of the analysis sent by the control device (22); and a data acquisition unit (504) that compares the results of the analysis received in this way and compares the vibration status of the machine tool of each of the manufacturing cells (104), in order to detect such a spindle fault in one of the machine tools that has a frequency spectrum intensity that differs from that of another machine tool, and wherein the communication unit (502) sends an error signal over the network when the detection unit (504) detects the spindle fault.

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to a management system that detects a spindle fault in a machine tool and comprises a management device that manages a plurality of machine tools connected to a network and that detects a spindle fault in the machine tool, as well as a non-volatile, computer-readable medium. It further relates to a method for detecting a spindle fault using the management device. Related technology

[0002] Traditionally, when a spindle failure occurs in a machine tool, the machining accuracy of the workpiece is affected, and a defective part may be produced. It should be noted that "spindle failure" refers to damage, wear, or deformation of any part of the spindle, as well as entering a state where the individual parts of the spindle can no longer perform their original function. An example would be a damaged spindle bearing, etc. Damage, wear, or deformation of components belonging to (installed on) the spindle, and entering a state where these components can no longer function, can be included under the term "spindle failure."

[0003] As a method to prevent the impairment of workpiece machining accuracy, etc., caused by a spindle fault, the use of a device that detects such faults has been considered. For example, it is known that if a spindle bearing or similar component is damaged, the balls (steel balls) forming the bearing, etc., generate vibrations of a specific frequency in the axial and radial directions of the spindle. Therefore, it has been considered to install an acoustic emission sensor or an accelerometer on the spindle to create a device that detects anomalies by analyzing the outputs of these sensors.

[0004] A block diagram of the configuration for anomaly detection for a machine tool, in which sensors are installed on the spindle in this way and a device is used that analyzes the sensor output, is in Fig. 4 shown. First, as in Fig. Figure 6 shows sensors 12a and 12b installed on the spindle 10. Sensor 12a is, for example, an acoustic emission sensor, and sensor 12b can be configured as an accelerometer. The output signals of these sensors 12a and 12b are amplified by an amplifier 14 and fed to an analysis device 16. The analysis device 16 is, for example, a computer, and outputs a fault detection signal when the output signals of sensors 12a and 12b are analyzed and an anomaly is detected. A program on the computer acting as the analysis device 16 performs an analysis of the output signals of sensors 12a and 12b using a predefined algorithm to determine whether an anomaly is present.Furthermore, for example, the principle of such an analysis device 16 and a method for detecting a spindle defect using a device such as the analysis device 16 are disclosed in patent document 1 listed below.

[0005] In contrast, patent document 2, listed below, discloses a method for detecting defects in any part of a machine tool by recording load fluctuations based on the value of the electrical current of a spindle motor or the like. The main objective of the method disclosed in this document is to detect load fluctuations, in particular damage to the tool based on these fluctuations. The method described in patent document 2 records and detects load fluctuations, that is, only a measure of the load, and does not record the fluctuations of specific frequencies.

[0006] Patent document 3 relates to an arrangement that can detect a spindle failure in a machine tool using an existing servo control device, without the need for separate external sensors, a failure analysis device, or similar components. A servo control device for detecting a spindle failure in a machine tool comprising the spindle, a feed shaft, and a positioning servomotor installed on the feed shaft that determines the spindle's position, includes: a feedback maintenance unit that receives a feedback signal from the positioning servomotor; and an analysis / detection unit that analyzes the received feedback signal to detect a spindle failure. Patent Document 1: JP-2005-74 545 A Patent Document 2: JP S52-95 386 A Patent document 3: DE 10 2017 213 787 A1 SUMMARY OF THE INVENTION

[0007] When using the conventional technology (Patent Document 1), in which the new sensor 12 is used in this way, the new sensor 12 and the analysis device 16 must be added, thus complicating the device configuration. Furthermore, space is required to install this sensor 12 and the analysis device 16. In addition, while the method for detecting load fluctuations based on the value of the motor's electrical current (Patent Document 2) can detect load-related phenomena, it has proven difficult to detect spindle defects, such as bearing damage. Moreover, this method does not record fluctuations of a specific frequency, as it only detects load fluctuations.

[0008] It is not assumed that this conventional fault detection technology can capture faults for a large number of machine tools simultaneously. Therefore, when a large number of machine tools are present in a network (e.g., a LAN within a factory, etc.), it is necessary to provide an analysis device for each machine tool and to capture the load fluctuations in each one. Consequently, the system as a whole is often complex and extensive. The present invention was developed in response to these problems, and one of its objectives is to provide a technology that enables the efficient detection of faults in a large number of machine tools connected via a network using a simpler configuration.

[0009] The inventors of the present disclosure have developed a novel technology for detecting spindle faults in a machine tool equipped with a spindle and a feed shaft, using the feedback from a servo motor used for spindle positioning. With this novel technology, a spindle fault can be detected by analyzing the feedback from the servo motor used for positioning in the spindle direction, which is identical to the axial vibrations that occur when a spindle fault occurs. Using this novel technology, it is possible to perform fault detection for the listed variety of machine tools. That is, by comparing the analysis results from the variety of machine tools, the present invention achieves efficient spindle fault detection with a simpler configuration.The means used in the present invention are listed in detail below.

[0010] For example, a management system (e.g., the production management system 30 described below) includes a network, a plurality of manufacturing cells (e.g., the manufacturing cell 104 described below) connected to the network, and a management device (e.g., the production management device 100 described below) connected to the network and managing the plurality of manufacturing cells, wherein the manufacturing cell includes a machine tool and a control device (e.g., the control device 22 described below) that controls the machine tool, analyzes a vibration status of a spindle positioning shaft of the machine tool, and sends a result of the analysis over the network, wherein the management device includes a communication unit (e.g.,the communication unit 502 described below, which receives the result of the analysis sent by the control device, and a detection unit (e.g. the detection unit 504 described below), which compares the results of the analysis received in this way and compares the vibration status of the machine tool of each of the manufacturing cells in order to detect a spindle fault of one of the machine tools, and wherein the communication unit, when the detection unit detects the spindle fault, sends a fault signal over the network.

[0011] For example, the management device included in the management system can contain a communication unit that receives the result of the analysis sent by the control device, as well as a detection unit that compares the received result of the analysis and compares the vibration status of the machine tools of each of the manufacturing cells in order to detect a spindle fault in one of the machine tools, whereby the communication unit can send a fault signal over the network when the detection unit detects the spindle fault.

[0012] For example, in the management device, the detection unit can compare frequency spectrum intensities of the vibration status of each of the machine tools based on the results of the analysis received in this way, detect a frequency spectrum that has an intensity that deviates by at least a predetermined threshold, and periodically monitor a change in the detected intensity of the spectrum in order to detect a spindle fault of the machine tool.

[0013] For example, in the management device, the detection unit can compare the frequency spectrum intensities of the vibration status of each of the machine tools based on the results of the analysis received in this way and determine that a spindle fault has occurred on the machine tool that has a frequency spectrum intensity that deviates by at least a predetermined threshold of intensity.

[0014] For example, in the management device, the communication unit can periodically receive spectral intensity of a given frequency range in the results of the analysis via the network.

[0015] For example, in the management system, the control device can perform frequency analysis on a feedback signal of a spindle positioning servomotor of the spindle positioning shaft of the machine tool in a predefined spindle state, determine a frequency spectrum intensity and send the result of the analysis including the frequency spectrum intensity.

[0016] For example, in the management device, when the detection unit detects the spindle fault, the communication unit can send a fault signal via the network to a higher-order control device and / or the manufacturing cell that contains the machine tool on which the fault was detected.

[0017] For example, in a method for detecting a spindle fault, by which a spindle fault on a machine tool is detected using the management device employed in the management system, the method includes a first communication step in which the result of the analysis sent by the control device is received, a detection step in which the result of the analysis thus received is compared, the vibration status of the machine tool in each of the manufacturing cells is compared and a spindle fault is detected in one of the machine tools, and a second communication step in which a fault signal is sent over the network when the spindle fault is detected in the detection step.

[0018] For example, in a computer program that enables a computer to function as the management device used in the management system, the program causes the computer to perform first communication processing, in which the result of the analysis sent by the control device is received; detection processing, in which the result of the analysis thus received is compared; the vibration status of the machine tool in each of the manufacturing cells is compared; and a spindle fault in one of the machine tools is detected; as well as second communication processing, in which an error signal is sent over the network if the spindle fault is detected during the detection processing.

[0019] According to the present invention, it is possible to perform fault detection on a large number of machine tools connected via a network without the need for special external sensors. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic representation of the overall structure of a production management system which includes a production management device according to the present invention; Fig. 2 is a configuration block diagram of a manufacturing cell according to the present embodiment; Fig. 3 is a configuration block diagram of a control device according to the present embodiment; Fig. 4 is a flowchart showing the functional sequences of the control device according to the present embodiment; Fig. 5 is a configuration block diagram of the production management system; and Fig. Figure 6 is a schematic representation of the setup of a conventional device for detecting a spindle fault. DETAILED DESCRIPTION OF THE INVENTION

[0020] Preferred examples of embodiments of the present invention are explained below with reference to the drawings. 1. Structure of the production management system, which includes the production management device of the present invention

[0021] Fig. Figure 1 is a schematic representation of the overall structure of a production management system 30, which includes a production management device 100 according to the present embodiment. The production management system 30 of the present embodiment is the production management system 30 of a plant, etc., in which a production management device 100, each manufacturing cell 104, and a higher-order management subsection 106 are connected via a network 102. The production management system 30 corresponds to a preferred example of a management system in the claims.

[0022] Network 102 is a communication network, such as a LAN (Local Area Network) within a factory, and can be wired or wireless. Furthermore, it can be configured as Ethernet, for example. The network also corresponds to a preferred example of a network in the claims. Manufacturing cell 104 is a manufacturing cell comprising a machine tool and a control device 22 that controls this machine tool. Although the present embodiment describes an example comprising one machine tool and one of the control devices 22, it can include a plurality of machine tools and / or a plurality of the control devices 22. Furthermore, the manufacturing cell corresponds to a preferred example of a manufacturing cell in the claims.

[0023] Fig. Figure 2 shows a configuration diagram illustrating a preferred example of manufacturing cell 104. To facilitate understanding, it shows Fig. 2. The structure of a part of the machine tool, that is, the structure around the spindle 10 as its center, as well as the control device 22, which controls the machine tool. The spindle 10 of the machine tool is supported by bearings 11 and can be rotated about its axis. Furthermore, according to the present embodiment, the machine tool includes a servo motor 20 for positioning the spindle 10 and can drive a feed shaft 21 to determine the position of the spindle 10 by causing this servo motor 20 to rotate. It should be noted that the feed spindle 21 corresponds to a preferred example of a spindle positioning shaft.

[0024] The machine tool according to the present embodiment controls, as in Fig. Figure 2 shows the servomotor 20 using this control device 22. Furthermore, a control signal output by the control device 22 is amplified by an amplifier 24 and then output to the servomotor 20. Additionally, a feedback signal is output from the servomotor 20 to the control device 22 (see Figure 2). Fig. 2).

[0025] The control device 22, according to the present embodiment, detects a spindle fault by analyzing the feedback signal received from the servo motor 20. With such a configuration, it is not necessary to provide special sensors or analysis devices, and it is possible to detect a spindle fault with a simpler configuration. With such a configuration, the control device 22 can analyze the feedback signal of the servo motor 20 in order to, for example, position it in the same direction as the vibrations that occur in the axial direction due to a spindle fault. The results of this analysis are then output externally via the network 102 as a vibration status signal (results of vibration analysis).These output results of the analysis can include various analysis results and can include a frequency spectrum intensity determined by means of Fourier transformation, etc. It should be noted that if the signal intensity of the vibrations in the axial direction exceeds a predetermined threshold, the control device 22 detects that a spindle fault has occurred and can output a detection signal indicating the fault.

[0026] Furthermore, information about the "spindle status," a signal indicating the start of the analysis, etc., can be supplied to the control device 22 from an external source; however, various detection operations can be performed using the same device. It should be noted that the control device 22 corresponds to a preferred example of a control device in the claims. Moreover, the servomotor 20 corresponds to a preferred example of a positioning servomotor in the claims. 2. Structure and function of control device 22.

[0027] Fig. Figure 3 shows a configuration diagram of the control device 22 of the present embodiment. The control device 22 is preferably configured, for example, as a computer, and each in Fig. The part shown is also preferably configured as the hardware (CPU, interface with each part) and programs (programs that implement each function of the control device 22) of a computer.

[0028] The control device 22 contains, as shown in Fig. 2 shown, a unit 222 for the relationship of feedback, a unit 224 for the control of the servo motor and an analysis / acquisition unit 226. 2.1 Feedback capture unit

[0029] The feedback unit 222 is an interface that receives a feedback signal supplied by the servo motor 20 and is suitable for use with a computer's I / O interface. Furthermore, if the feedback signal output by the servo motor 20 is an analog signal, the feedback unit 222 can be equipped with an A / D conversion function to convert this signal into a digital signal. The feedback unit 222 supplies a feedback signal obtained in this way to the analysis / acquisition unit 226. The reception and processing of this feedback signal corresponds to step S4-1 in [reference missing]. Fig. 4. The feedback signal output by the servomotor 20 can be at least one type representing a value of electrical current, speed, or position of the servomotor 20. These signals represent the function of the servomotor 20, and therefore it is assumed that a spindle fault can be detected more accurately by analyzing one of these signals. The feedback unit 222 feeds these signals, after the necessary conversion into digital signals, to the analysis / acquisition unit 226.

[0030] The unit 222 for the relationship of feedback is formed, as mentioned above, by hardware, such as an I / O interface and an A / D conversion device, but can be formed by programs that control this I / O interface, A / D conversion device, etc., as well as the CPU of a computer that executes these programs. 2.2 Unit for controlling the servo motor

[0031] The unit 224 for controlling the servo motor outputs control signals for the servo motor 20 (not shown) in response to commands from an external control device. The amplifier 24 in Fig. 1 amplifies the control signal to an electrical power sufficient to drive the servomotor 20 and applies the amplified control signal to the servomotor 20. This unit 224 for controlling the servomotor consists of an interface that outputs the control signal externally, a program that generates the control signal based on commands from a higher-order control device, and the CPU of a computer that executes this program. 2.3 Analysis / Data Collection Unit

[0032] The analysis / acquisition unit 226 analyzes the feedback signal related to the feedback relationship via unit 222. In the present embodiment, analysis is processing to convert the feedback signal into frequency spectrum intensity using Fourier transforms, etc. This analysis / acquisition unit 226 analyzes the feedback signal; however, in the present embodiment, an example of performing the analysis is specifically described in the case where the machine tool is in a non-machining state. Of course, the feedback signal can also be analyzed when a machining state exists. Whether a non-machining state exists or not can be determined using various external signals. Whether the machine tool is in a machining state can be determined using various methods.For example, a signal from an external control device is suitable for determining whether the machine tool is in a machining state or a non-machining state. Although the external control device is preferably a numerical control or the like, it can be various computers or terminals operated by a person. The analysis / acquisition unit 226 thus performs processing to check whether the machine tool is in a machining state or a non-machining state, and this processing corresponds to step S4-2 in . Fig. 4.

[0033] When the machine tool is in a non-machining state, the analysis / acquisition unit 226 performs a Fourier transformation on the feedback signal to convert it into frequency spectrum intensity.

[0034] The analysis / acquisition unit 226 can transmit the determined frequency spectrum intensity unchanged as the result of the analysis in the network 102; however, the data volume is often exceptionally large. Therefore, in the present embodiment, the analysis / acquisition unit 226 acquires the frequency whose frequency spectrum intensity has an amplitude (peak value) of at least one predefined threshold and transmits only the frequency at which this intensity (amplitude / peak value) is high as the result of the analysis. Since it is thus possible to transmit only the characteristic frequency, the production management device 100, which has received these signals, can efficiently determine the fault condition of the machine tool with minimal information.It should be noted that if the amplitude values ​​of at least one given threshold are plentiful, preferably only frequencies of the highest order Kt are transmitted in descending order. K is a natural number at least 1, and ideally, for example, the natural numbers between 2 and 20 are used. It should be noted that, generally speaking, the frequency spectrum with the greatest amplitude is the spindle rotation frequency; however, since this frequency is obvious, it is suitably excluded and not included in the results of the analysis. It should be noted that, although an example of capturing the magnitude of the amplitude, that is, the peak value of the spectrum, is presented here, the intensity can be determined for any given frequency range. In this case, the intensity of each corresponding frequency band can be included in the results of the analysis to be transmitted.Furthermore, the frequency spectrum intensities determined by means of Fourier transformation are appropriately excluded, since it is obvious that frequencies that are too high or too low cannot serve as the subject of analysis.

[0035] The analysis / acquisition unit 226 then transmits the analysis results thus obtained to the control device 22 via the network 102. The transmission and processing of these analysis results corresponds to step S4-4 in Fig. 4. The results of the analysis are sent to each corresponding manufacturing cell 104, collected in the production management device 100 via the network 102, and used in determining a spindle defect. It should be noted that this transmission and processing is preferably performed at fixed intervals. Various cycles can be used as this interval. The analysis / acquisition unit 226 can also be configured as programs that implement the functions described above, a CPU that executes these programs, and an interface with the network 102. These programs correspond to a preferred example of a computer program in the claims. 3. Detection of a spindle fault

[0036] In the present embodiment, the results of the analysis from the plurality of manufacturing cells 104 are transmitted via the network 102 in this manner. These analysis results are elements indicating the operating state of the machine tool contained in the manufacturing cell 104. When transmitting the operating state, that is, the feedback signal itself, its information load tends to become extremely large. Therefore, in the present embodiment, it is configured to be converted into frequency spectrum intensity, and only information of a frequency with a high intensity is transmitted. This makes it possible to reduce the information volume and quickly acquire the operating states of machine tools in the production management device 100.

[0037] In the present embodiment, it is assumed that the basic specifications of the machine tools to be managed, at least the spindle specifications, are identical. This is because fault detection is facilitated when the specifications are the same, as a fault generates a signal of a different frequency than those of the other machine tools. Furthermore, it is assumed that each spindle rotates at the same speed in the non-machining state. In the machining state, however, fault diagnosis proves difficult, as signals of different frequencies occur depending on the nature of the machining operation. Based on these assumptions, the following section describes the detection of a spindle fault on a plurality of machine tools connected via network 102. 3.1 Principles 1) Principle 1

[0038] It is known that before a spindle failure occurs, a component (its amplitude) that has a frequency spectrum within the spindle's vibration becomes more pronounced. However, different components become more pronounced depending on the machine tool. Therefore, when attempting to detect a spindle failure using such a characteristic, the frequency spectrum is preferably recorded beforehand during normal operation. Failure detection can then be performed by regularly (periodically) checking the frequency spectrum intensity of this machine tool and comparing it with the previous frequency spectrum intensity. That is, if the machine tool's frequency spectrum is recorded regularly, the spectrum recorded during machining is appropriately used. However, this principle requires recording data beforehand during normal operation, and therefore a fixed preparation period before failure detection is necessary. 2) Principle 2

[0039] Therefore, the explanation of the present embodiment focuses on a method in which frequency spectrum intensities are compared between all machine tools without requiring the recording of frequency spectrum intensity during normal operation. By performing a relative comparison of the spectrum between machine tools with the same specifications, it is possible to identify the machine tool exhibiting the phenomenon described above. In the present embodiment, spindle rotation is performed at the same speed using the same types of machine tools. This is carried out regularly (periodically), and the feedback signal at that time is analyzed in each control device 22. The results of the analysis are then transmitted via the network 102 to the production management device 100.Furthermore, the control device 22 appropriately extracts, for example, the highest (e.g., fifth highest) frequency of the frequency spectrum intensity as a result of the analysis and sends it as a selection result. The production management device 100 compares the transmitted results of the analysis of the respective machine tools and can thus identify a machine tool that has a frequency spectrum intensity that differs from that of the other machine tools. This means that, for example, if an anomaly occurs at the spindle of a particular machine, a very specific frequency component is detected in its frequency spectrum intensity. In this case, when an anomaly occurs, the higher-order management subsection is notified of this and / or the manufacturing cell 104 of the machine tool in which this anomaly occurred.According to the present embodiment, it is possible to perform fault diagnosis using this processing even when the manufacturing cell 104 is set up using a new machine tool whose vibration frequency spectrum is unknown when a fault occurs. 4. Configuration of the production management device and its function.

[0040] Fig.Figure 5 shows a configuration diagram of the production management system 30, centered around the configuration block diagram of the production management device 100. The production management device 100 consists of a communication unit 502, a data acquisition unit 504, a monitoring unit 506, a comparison unit 508, a database 510, and a bus 512 connecting these elements. The production management device 100 is essentially a computer, and each component consists primarily of a computer program that implements its functions and a CPU that executes this computer program. 4.1 Communication Unit

[0041] The Communication Unit 502 is an interface with the Network 102 and is configured as hardware that serves as the interface, a computer program that controls it, and a CPU that executes the computer program. 4.2 Data Acquisition Unit

[0042] The acquisition unit 504 is a section that acquires the analysis results received via the communication unit 502 and is configured as a computer program that performs its functions, as well as a CPU that executes it. When the communication unit 502 receives the analysis results, the acquisition unit of this embodiment compares them between the machine tools. That is, it compares the vibration status. Then, if the vibration status of one machine tool differs from others, this is determined to be a spindle fault. When a spindle fault is detected, the manufacturing cell 104, in which the corresponding machine tool is contained, is informed of this fact, and processing, such as interruption, is carried out.Furthermore, a report is simultaneously sent to the higher-order management section, allowing the machine tool on which the spindle fault occurred and its manufacturing cell to be reported. This comparison is specifically implemented by comparing transmitted frequencies. The frequencies are compared as described above when a number k of frequencies are transmitted in descending order of frequency spectrum intensity. If the frequencies are identical, it is determined that no fault has occurred. However, since it is assumed that they are not completely identical and include a certain degree of variation, it is useful to determine that these frequencies are identical if there is a difference on the order of a predetermined ratio of m%, where m is a predetermined real number.For example, it is also useful to choose between 0, 1 and 10. A choice between 0, 1 and 20 is also possible. The detection unit 504 corresponds to a preferred example of a detection unit in the patent claims. Monitoring unit, comparison unit and database

[0043] The monitoring unit 506 monitors the frequency spectrum intensity and records it in the database 510. The comparison unit 508 compares the transmitted frequency spectrum intensity with a previous frequency spectrum, and if a difference exceeds a predefined threshold, a spindle fault is detected. When a spindle fault occurs, the comparison unit 508 reports this to the detection unit 504, which then informs the manufacturing cell containing the machine tool where the spindle fault occurred and notifies the higher-order management subsection in a manner similar to that described above. The monitoring unit 506 and the comparison unit 508 are configured as a computer program that performs the functions listed above and a CPU that executes this computer program.Furthermore, database 510 can be configured as a predefined storage device. Modified examples

[0044] 1) Although a feedback signal is used in the embodiment described above, the feedback signal can be any signal representing the electric current, speed, or position of the servomotor 20. Furthermore, any signal can be used as the feedback signal, provided it represents the function of the servomotor 20. In addition, the "speed" can be the angular velocity or the rotational speed (rpm, etc.). Furthermore, the "position" can be the angle of rotation or the degree of rotation (angle). Furthermore, it can be just one signal representing the electric current, speed, or position, or two or more different signals can be used.

[0045] 2) In the embodiment described above, amplitude and peak value are explained as the frequency spectrum intensity. Furthermore, the intensity of the signal can, for example, be the root mean square or an average value. EXPLANATION OF REFERENCE SYMBOLS 10 spindles 11 warehouses 12, 12a, 12b Sensor 14, 24 amplifiers 16 Analysis device 20 servo motor 21 Feed shaft 22 Control device 30 Production Management System 100 Management Device 102 Network 104 manufacturing cell 106 Management Subsection of Higher Order 222 Unit on the relationship of feedback 224 Unit for controlling servo motors 226 Analysis / Data Collection Unit 502 Communication Unit 504 Recording Unit 506 Monitoring Unit 508 comparison unit 510 database 512 Bus

Claims

[1] Management system (30) comprising a network, a plurality of manufacturing cells (104) connected to the network, and a management device (100) connected to the network and managing the plurality of manufacturing cells (104), wherein the manufacturing cell (104) contains: a machine tool of the same type as a machine tool in another of the manufacturing cells; as well as a control device (22) that controls the machine tool, analyzes a vibration status of a spindle positioning shaft of the machine tool and sends a result of the analysis via the network, wherein, in the case that the machine tool is in a non-processing state, the control device sends over the network, as a result of the analysis, only a frequency spectrum intensity which has at least one predetermined value from frequency spectrum intensities obtained by performing a Fourier transform of a feedback signal of a spindle-positioning axial servomotor when the spindle of the machine tool rotates at the same rotational speed as a machine tool in another of the manufacturing cells, and the management device (100) contains: a communication unit (502) that receives the result of the analysis sent by the control device (22); and a data acquisition unit (504) that compares the results of the analysis received in this way and compares the vibration status of the machine tool of each of the manufacturing cells (104), in order to detect such a spindle fault in one of the machine tools that has a frequency spectrum intensity that differs from that of another machine tool, and wherein the communication unit (502) sends an error signal over the network when the detection unit (504) detects the spindle fault. [2] Management system (30) according to claim 1, wherein the detection unit (504) compares frequency spectrum intensities of the vibration status of each of the machine tools on the basis of the results of the analysis thus received, detects a frequency spectrum which has an intensity which deviates by at least a predetermined threshold, and periodically monitors a change in the intensity of the detected spectrum in order to detect a spindle fault of the machine tool. [3] Management system according to claim 1 or 2, wherein the detection unit (504) compares frequency spectrum intensities of the vibration status of each of the machine tools on the basis of the results of the analysis thus received and determines that a spindle fault has occurred on the machine tool which has a frequency spectrum intensity that deviates by at least a predetermined threshold of intensity. [4] Management system according to one of claims 1 to 3, wherein the communication unit (502) periodically receives spectral intensity of a predetermined frequency range in the results of the analysis via the network. [5] Management system according to any one of claims 1 to 4, wherein the communication unit (502), when the detection unit (504) detects the spindle fault, sends a fault signal via the network to a higher order control device and / or the manufacturing cell which includes the machine tool on which the fault was detected. [6] Method for detecting a spindle fault, wherein a spindle fault on a machine tool is detected using the management device (100) used in the management system (30) according to claim 1, the method comprising: a first communication step in which the result of the analysis sent by the control device (22) is received; a data acquisition step in which the result thus obtained from the analysis is compared, the vibration status of the machine tool in each of the manufacturing cells (104) is compared, and a spindle fault in one of the machine tools that has a frequency spectrum intensity that differs from that of another machine tool is detected; as well as a second communication step in which an error signal is sent over the network if the spindle error is detected in the detection step. [7] Non-volatile, computer-readable medium on which a computer program is encoded that enables a computer to operate as the management device used in the management system (30) according to claim 1, wherein the program causes the computer to execute: first communication processing in which the result of the analysis sent by the control device (22), according to which only one frequency spectrum intensity has an intensity of at least a predetermined value, is received; Acquisition processing in which the result thus received from the analysis is compared, the vibration status of the machine tool in each of the manufacturing cells (104) is compared, and a spindle fault in one of the machine tools that has a frequency spectrum intensity that differs from that of another machine tool is detected; as well as Second communication processing, in which an error signal is sent over the network if a spindle error is detected during the acquisition processing.

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