Vibration diagnosis assistance device, vibration diagnosis assistance method, and machine tool

Abstract

The vibration diagnosis assisting device (50) of one embodiment of the present application acquires a swing frequency characteristic of the rotating shaft when the movable mechanism (30) swings in accordance with the first swing command signal (SS1) or the second swing command signal (SS2) in a state in which the rotating shaft is rotating in accordance with the rotation command signal (RS) for each of a plurality of rotational speeds that are set in advance, and causes the acquired swing frequency characteristic to be displayed on the display device (56).

Description

TECHNICAL FIELD

[0001] The present application relates to a vibration diagnosis assisting device, a vibration diagnosis assisting method, and a machine tool. BACKGROUND

[0002] In a machine tool, in order to grasp the vibration characteristics of the machine tool, a motor mounted on the machine tool is sometimes used as an excitation source to measure the frequency characteristics. For example, in the servo control device of Japanese Patent Laid-Open No. 2016-111897, it is disclosed that the resonance frequency is detected from the frequency characteristics. The frequency characteristics include the gain of the input signal of a sine wave input to the speed control circuit for the servo motor and the output signal output from the speed control circuit when the input signal is input. SUMMARY

[0003] However, the servo control device of Japanese Patent Laid-Open No. 2016-111897 does not grasp the vibration that changes depending on the cause of the vibration. For example, in the case of the natural frequency unique to the rotating shaft or the like, the vibration changes depending on the rotational speed (rotational frequency) of the rotating shaft. Further, for example, in the case of loosening of the bolt or the like, the generation method of the vibration changes depending on the excitation condition. Further, the servo control device of Japanese Patent Laid-Open No. 2016-111897 does not have a function of grasping the origin of the vibration.

[0004] Further, in a precision machine tool that requires particularly high machining accuracy, it is important to grasp the following matters. Specifically, it is important to grasp how far the rotational speed (rotational frequency) of the rotating shaft is from the nearest resonance frequency. In other words, it is important to grasp in which band the rotational speed at which the rotating shaft rotates more stably and quietly exists. However, in the past, it was difficult for the precision machine tool to determine the above matters. Further, in the past, there was no function of identifying and indicating the "recommended machining rotational speed" or the "recommended spindle rotational speed" at which machining can be performed with high accuracy.

[0005] Therefore, a first object of the present application is to provide a vibration diagnosis assisting device, a vibration diagnosis assisting method, and a machine tool that can grasp the frequency characteristics taking into account the movement of the natural frequency, the resonance point, and the like. Further, a second object of the present application is to provide a vibration diagnosis assisting device, a vibration diagnosis assisting method, and a machine tool that facilitate ultra-precision machining. In a precision machine tool, it is extremely effective to grasp the distribution of the resonance points of the spindle for each rotational speed of the spindle. It is possible to add a function of explicitly indicating the distribution of the vibration and further indicating the "recommended machining rotational speed" or the "recommended spindle rotational speed". Thereby, it is possible to provide an assisting function that allows an operator to know the recommended rotational speed at which machining can be performed with high accuracy, and even an unskilled operator can easily know the candidate of the ideal machining rotational speed.

[0006] A first aspect of the present application is a vibration diagnosis assisting device that assists diagnosis of vibration of a rotating shaft portion of a machine tool having a numerical control device, and includes:

[0007] A movable mechanism mounted on the machine tool;

[0008] A mechanism control portion that drives the movable mechanism;

[0009] A swing command signal sending portion that sends a first swing command signal that changes in a manner in which the frequency increases over time or a second swing command signal that changes in a manner in which the frequency decreases over time to the mechanism control portion;

[0010] A rotating shaft control portion that rotates a rotating shaft mounted on the rotating shaft portion;

[0011] A rotation command signal sending portion that sends a rotation command signal to the rotating shaft control portion;

[0012] An acquisition portion that acquires a swing frequency characteristic of the rotating shaft when the movable mechanism swings in accordance with the first swing command signal or the second swing command signal in a state in which the rotating shaft is rotating in accordance with the rotation command signal for each of a plurality of rotational speeds that are set in advance; and

[0013] A display control portion that causes the swing frequency characteristic acquired by the acquisition portion to be displayed on a display device.

[0014] A second aspect of the present application is a machine tool that includes the vibration diagnosis assisting device described above, at least one of the rotating shaft portion and the main shaft portion, and at least one of the movable mechanisms.

[0015] Further, the vibration diagnosis assisting device can be installed in the numerical control device mounted on the machine tool in the form of a function, or can be constructed in a personal computer and connected to the numerical control device to send a command to the numerical control device. In addition, the rotating shaft and the movable mechanism can be each axis mounted on the machine tool and controlled by the numerical control device.

[0016] A third aspect of the present application is a vibration diagnosis assisting method that assists diagnosis of vibration of a rotating shaft portion of a machine tool, and includes:

[0017] A rotating step of rotating a rotating shaft mounted on the rotating shaft portion in accordance with a rotation command signal;

[0018] A swing step of causing a movable mechanism of the machine tool to swing in accordance with a first swing command signal that changes in a manner in which the frequency increases over time or a second swing command signal that changes in a manner in which the frequency decreases over time.

[0019] acquiring, for each of a plurality of predetermined rotational speeds, a swing frequency characteristic when the movable mechanism swings in accordance with the first swing command signal or the second swing command signal in a state in which the rotational shaft is rotating in accordance with the rotation command signal; and

[0020] displaying the swing frequency characteristic acquired in the acquiring step on a display device.

[0021] Thus, the natural vibration frequency having a property unique to the rotational shaft and the resonance point that moves depending on the property of the excitation source are taken into consideration. Therefore, a more detailed frequency characteristic of the rotational shaft portion can be exhibited. Furthermore, a detailed distribution of the natural vibration frequency can be exhibited. As a result, a rotational speed that is as far as possible from the natural vibration frequency and rotates more quietly can be easily found. Especially in the case of a main shaft as the rotational shaft, a high-precision machined surface can be easily obtained. Furthermore, the cause of abnormal vibration can be inferred using the result. Especially in a precision machine tool that requires high machining precision, higher-precision machining can be achieved, and great value can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic view showing a machine tool.

[0023] Figure 2 is a block diagram showing the configuration of a control unit.

[0024] Figure 3 is a view showing an example of a swing command signal.

[0025] Figure 4 is a view showing an example of a display of a swing frequency characteristic.

[0026] Figure 5 is a flowchart showing the flow of a vibration diagnosis assistance process.

[0027] Figure 6 is a view showing a part of a vibration diagnosis assistance device of Modification Example 1.

[0028] Figure 7 is a view showing an example of a second swing command signal.

[0029] Figure 8 is a view showing a part of a vibration diagnosis assistance device of Modification Example 4. DETAILED DESCRIPTION

[0030] 〔Embodiment〕

[0031] Figure 1A schematic view of a machine tool 10 is shown. The machine tool 10 performs machining of a workpiece using a tool. The machine tool 10 can be a precision machine tool having a machining accuracy of 100 μm or less. Further, the machine tool 10 can also be an ultra-precision machine tool having a machining accuracy of 10 μm or less. Furthermore, the machine tool 10 can be a lathe or a machining center. The lathe performs machining by bringing a workpiece in a rotating state into contact with a fixed tool. The machining center performs machining by bringing a tool in a rotating state into contact with a fixed workpiece. The machine tool 10 includes a machine tool main body 12 and a control unit 14.

[0032] The machine tool main body 12 is a main body that performs machining of a workpiece using a tool. The machine tool main body 12 includes a spindle portion 20 as a rotational axis portion, a movable mechanism 30, and a measurement portion 40.

[0033] The spindle portion 20 supports a spindle 22 in such a manner that the spindle 22 is movable in a prescribed direction. In the case where the machine tool 10 is a lathe, the spindle portion 20 corresponds to a spindle head. In the case where the machine tool 10 is a machining center, the spindle portion 20 corresponds to a spindle head. The spindle portion 20 includes the spindle 22, a spindle motor 24, a coupling member 26, and a fixed member 28.

[0034] The spindle motor 24 drives the spindle 22. The spindle motor 24 can be a direct drive type built-in motor. The coupling member 26 couples the spindle motor 24 and the spindle 22. The coupling member 26 can include a gear, a belt, a coupling, a joint, or the like. Furthermore, in the case where the spindle motor 24 is a built-in motor, the spindle motor 24 is directly connected to the spindle 22, and thus the coupling member 26 is not provided. That is, the spindle portion 20 can not be provided with the coupling member 26. The fixed member 28 indicates a member such as a stator of the spindle motor 24 that does not rotate in conjunction with the spindle 22. The fixed member 28 can also be a housing such as a motor housing or a spindle housing.

[0035] The movable mechanism 30 is a mechanism that performs movement in a movable axis direction of the machine tool 10. The movable mechanism 30 includes a linear axis or a rotational axis. The direction in which the movable mechanism 30 performs movement is arbitrary. The direction in which the movable mechanism 30 performs movement can be a first direction in which the spindle 22 extends. Further, the direction in which the movable mechanism 30 performs movement can be a second direction that is orthogonal to the first direction in a plane. Further, the direction in which the movable mechanism 30 performs movement can be a third direction that is orthogonal to each of the first direction and the second direction. Furthermore, the direction in which the movable mechanism 30 performs movement can be a direction other than the first direction, the second direction, and the third direction. Further, in the case of a rotational axis, the direction in which the rotational axis extends is also arbitrary. The movable mechanism 30 can function as a vibration source that vibrates the spindle portion 20. The spindle portion 20 can or can not be mounted to the movable mechanism 30. The movable mechanism 30 includes a servo motor 32, a power transmission portion 34, and a support member 36.

[0036] The servo motor 32 can be a linear motor or a rotary motor. The power transmission portion 34 transmits the driving force of the servo motor 32 to the support member 36. The power transmission portion 34 can be a ball screw or the like that converts the driving force (rotational force) of the servo motor 32 into a linear forward motion and transmits it to the support member 36. Alternatively, the power transmission portion 34 can directly transmit the driving force (thrust) of the servo motor 32 to the support member 36. Furthermore, the power transmission portion 34 can include a gear, a belt, a coupling, a joint, or the like. The support member 36 supports a movable object. In the case where the spindle portion 20 is mounted on the movable mechanism 30, the movable object is the spindle portion 20. In this case, the support member 36 supports the fixing member 28 of the spindle portion 20. On the other hand, in the case where the spindle portion 20 is not mounted on the movable mechanism 30, the movable object is another member that is different from the spindle portion 20. In this case, the support member 36 supports the other member that is different from the spindle portion 20.

[0037] The measurement portion 40 measures a physical quantity used to obtain the state of the spindle portion 20. As the physical quantity, at least one of the magnitude of sound (sound pressure or the like), the magnitude of vibration (displacement, velocity, acceleration, or the like), the angle of the spindle 22, the angular velocity, the angular acceleration, or the like is used. The physical quantity that represents the magnitude of vibration can also be the rotational direction of the spindle 22. The measurement portion 40 can be provided at any position of the machine tool main body 12. In general, it is preferable to be closer to the spindle portion 20 that is the measurement target rotary shaft (spindle 22). The reason for this is that the effect of excitation is easily transmitted and measurement can be performed more accurately. The measurement portion 40 can include a sensor mounted on the machine tool 10. In particular, a detector used for the control of each movable shaft of the machine tool 10 is preferable. A detector that is particularly selected so as to more easily measure the vibration of the target rotary shaft portion (spindle portion 20) can be included in the measurement portion 40. In the case where the drive source of each shaft is a motor, the driving current thereof can be used as the physical quantity that represents the magnitude of vibration. In particular, the current value at which the stop state is to be maintained is suitable as the physical quantity that represents the magnitude of vibration. In the present embodiment, the measurement portion 40 measures the rotational angle (position) of the servo motor 32.

[0038] The control unit 14 controls the machine tool main body 12. Figure 2A block diagram showing the configuration of the control unit 14. The control unit 14 has a vibration diagnosis assistance device 50, an input device 52, a storage device 54, and a display device 56. The vibration diagnosis assistance device 50 assists in the diagnosis of the vibration of the spindle portion 20. The vibration diagnosis assistance device 50 can be a numerical control device that controls the machine tool main body 12, or a general-purpose personal computer. In the case where the vibration diagnosis assistance device 50 is a general-purpose personal computer, the numerical control device that controls the machine tool 10 is connected to the personal computer. The input device 52 inputs information. The input device 52 can be a keyboard, a mouse, or the like, or an input key mounted on the numerical control device. The storage device 54 stores information. The storage device 54 can be a hard disk, a portable memory, or the like. The display device 56 displays information. The display device 56 can be a liquid crystal display, an organic EL display, or the like. Furthermore, the input device 52 and the display device 56 can be integrated, for example, like a teach pendant. Alternatively, the input device 52 and the display device 56 can be mounted on the numerical control device, or can be connected to the general-purpose personal computer.

[0039] The vibration diagnosis assistance device 50 has a processor such as a CPU, a GPU, and a storage portion. The storage portion includes a volatile memory such as a RAM and a non-volatile memory such as a ROM, a flash memory, and a hard disk. At least a part of the storage portion can be provided in the processor. The vibration diagnosis assistance device 50 of the present embodiment has a rotation command signal sending portion 72, a spindle control portion 74, a swing command signal sending portion 76, a mechanism control portion 78, an acquisition portion 80, and a display control portion 82. The rotation command signal sending portion 72, the spindle control portion 74, the swing command signal sending portion 76, the mechanism control portion 78, the acquisition portion 80, and the display control portion 82 can be realized by processing a program stored in the storage portion by the processor. Furthermore, at least one of the rotation command signal sending portion 72, the spindle control portion 74, the swing command signal sending portion 76, the mechanism control portion 78, the acquisition portion 80, and the display control portion 82 can be realized by an integrated circuit such as an ASIC or an FPGA. Furthermore, at least one of the rotation command signal sending portion 72, the spindle control portion 74, the swing command signal sending portion 76, the mechanism control portion 78, the acquisition portion 80, and the display control portion 82 can be constituted by an electronic circuit including discrete devices.

[0040] The rotation command signal sending portion 72 sends a rotation command signal RS to the spindle control portion 74. The rotation command signal RS is a signal that specifies the rotational speed (spindle rotational speed) of the spindle 22. The spindle control portion 74 controls the spindle motor 24 of the spindle portion 20 in accordance with the rotation command signal RS, thereby causing the spindle 22 to rotate. Furthermore, in the case where the rotational speed specified by the rotation command signal RS is zero, the spindle 22 is in a non-rotating state (a stationary state).

[0041] The swing command signal sending section 76 sends a swing command signal SS to the mechanism control section 78. The swing command signal SS is a signal that controls the servo motor 32. That is, the swing command signal SS is a signal for causing the servo motor 32 to repeatedly perform a swing operation. The so-called swing operation is an operation in which the motor shaft of the servo motor 32 is reversed after being rotated (displaced) in the positive direction from a reference position that is set in advance, and is reversed after being rotated (displaced) in the negative direction through the reference position. Incidentally, the so-called swing operation is an operation in which the motor shaft of the servo motor 32 alternately repeats positive rotation and negative rotation between a first rotation position and a second rotation position. Further, the first rotation position is a position in which the motor shaft of the servo motor 32 is rotated (displaced) in the positive direction from the reference position by a prescribed amount, and the second rotation position is a position in which the motor shaft of the servo motor 32 is rotated (displaced) in the negative direction from the reference position by a prescribed amount.

[0042] Figure 3 A graph showing an example of the swing command signal SS is shown in FIG. 6. The value "0" of the swing command signal SS indicates the reference position. Further, the value of the swing command signal SS having a + sign (positive sign) indicates the rotation angle (displacement amount) of the servo motor 32 that is rotated in the positive direction from the reference position. The value of the swing command signal SS having a - sign (negative sign) indicates the rotation angle (displacement amount) of the servo motor 32 that is rotated in the negative direction from the reference position. The greater the value (absolute value) of the swing command signal SS departs from the reference position "0", the greater the rotation angle (displacement amount) of the servo motor 32 from the reference position.

[0043] The swing command signal SS is changed (chirped) so as to gradually increase in frequency as time elapses. The "gradually increase in frequency" includes a case in which the frequency is continuously and smoothly increased without interruption, or a case in which the frequency is increased in stages. In addition, the swing command signal SS can be changed so as to gradually increase in frequency as time elapses within a predetermined frequency range.

[0044] The swing of the servo motor 32 (movable mechanism 30) following the swing command signal SS becomes faster as time elapses. Further, the amplitude of the swing command signal SS can be fixed without changing with time. In the case in which the amplitude is fixed without changing with time, the rotation angle (displacement amount) of the servo motor 32 that is rotated (displaced) in the positive direction from the reference position and the rotation angle (displacement amount) of the servo motor 32 that is rotated (displaced) in the negative direction from the reference position are the same rotation angle.

[0045] The mechanism control section 78 periodically swings the servo motor 32 in accordance with the swing command signal SS. The movable mechanism 30 swings in accordance with the swing of the servo motor 32, and thus the spindle portion 20 of the support member 36 that is supported to the movable mechanism 30 is swung. That is, the mechanism control section 78 controls the servo motor 32 in accordance with the swing command signal SS, and thus causes the movable mechanism 30 to swing as a vibration source for the spindle portion 20.

[0046] The acquisition section 80 acquires the wobble frequency characteristic of the movable mechanism 30 in a state where the main shaft 22 is rotating in accordance with the rotation command signal RS. The wobble frequency characteristic is a frequency characteristic when the movable mechanism 30 wobbles as an excitation source in accordance with the wobble command signal SS. The acquisition section 80 acquires the wobble frequency characteristic for each of a plurality of main shaft rotational speeds that are set in advance.

[0047] When the acquisition section 80 receives the measurement start command from the input device 52, the rotation command signal output section 72 outputs a switching signal to sequentially switch the main shaft rotational speed specified by the rotation command signal RS to a certain rotational speed among the plurality of main shaft rotational speeds that are set in advance.

[0048] Further, the acquisition section 80 acquires the wobble frequency characteristic in accordance with the wobble command signal SS and the measurement signal MS at each prescribed time interval. The measurement signal MS is a signal measured by the measurement section 40 when the movable mechanism 30 is wobbling in accordance with the wobble command signal SS. When the acquisition section 80 acquires the wobble frequency characteristic, the wobble frequency characteristic is stored to the storage device 54.

[0049] As the wobble frequency characteristic, the frequency characteristic of any one of the amplitude (displacement), the velocity, the acceleration, and the sound pressure is used. In the case of the present embodiment, the wobble frequency characteristic is set to the gain characteristic of the amplitude ratio of the wobble command signal SS and the measurement signal MS at each of a plurality of wobble frequencies. In this case, the amplitude ratio of the input signal (wobble command signal SS) input to the servo motor 32 and the measurement signal MS measured by the measurement section 40 in correspondence with the input signal is acquired for each wobble frequency. In addition, the acquisition section 80 can acquire the power spectral density in correspondence with each of a plurality of wobble frequencies as the wobble frequency characteristic. In this case, the acquisition section 80 can acquire the power spectral density from the Fourier spectrum of the waveform of the sound pressure, the vibration, the current at the time of the rest of the other shaft, or the like.

[0050] The display control section 82 causes the wobble frequency characteristic acquired by the acquisition section 80 in accordance with each of the plurality of main shaft rotational speeds that are set in advance to be displayed on the display device 56. Thereby, the display control section 82 can cause the operator to recognize the rotation frequency that is suitable for processing. That is, the main shaft rotational speed region in which the main shaft 22 stably and quietly rotates can be selected. If processing is performed at the main shaft rotational speed in which the main shaft 22 stably and quietly rotates, the processing conditions such as the dimension, the surface roughness, or the like can be realized with high processing precision. This effect is particularly good in a super-precision machine in which the processing precision is 10 nm or less and a fine processing precision is required.

[0051] Figure 4A graph of a display example of the wobble frequency characteristic. The display control section 82 can cause the wobble frequency characteristic of each main shaft rotational speed acquired by the acquisition section 80 to be displayed on the display device 56 in the form of a characteristic graph GF. Further, the characteristic graph GF can be a graph of a three-dimensional display in which the first axis is set as the main shaft rotational speed, the second axis is set as the wobble frequency, and the third axis is set as the vibration amount Figure 4 ). The vibration amount is an amount indicating the magnitude of the vibration. The vibration amount can be the amplitude, the velocity, the acceleration, the magnitude of the sound (sound pressure), or the power spectral density calculated from the Fourier spectrum thereof. The magnitude of the vibration can be indicated in absolute values or in relative values. Further, it can be a graph of a two-dimensional display in which the first axis is set as the main shaft rotational speed and the second axis is set as the wobble frequency. In the case of the two-dimensional display, the magnitude of the vibration can be made to be understood by devising the size, the color, the shape, or the like of the graph. Figure 4 The main shaft rotational speed indicated can also be converted into the rotational frequency [Hz].

[0052] The display control section 82 can cause the transport line TL to be displayed as an auxiliary line together with the characteristic graph GF. The transport line TL is an auxiliary line connecting points at which the rotational frequency corresponding to the main shaft rotational speed and the wobble frequency are equal, and is drawn on a plane including the first axis and the second axis.

[0053] The display control section 82 can also display a line LN connecting the crests of the waveforms (three-dimensional waveforms or two-dimensional waveforms) indicating the frequency characteristics on the characteristic graph GF. The line LN is drawn by projecting the two-dimensional transport line TL onto the three-dimensional characteristic graph GF. That is, the line LN is a line intersecting the surface of the characteristic graph GF by a plane (transport plane) passing through the transport line TL and parallel to the third axis. The display control section 82 can also emphasize the line LN. For example, the display control section 82 can display the transport line TL on the characteristic graph GF, and extract the line LN from the characteristic graph GF, thereby emphasizing the line LN (see FIG. 9). Figure 4 Further, the display control section 82 can distinguish the line LN from other waveforms by color on the characteristic graph GF, thereby emphasizing the line LN.

[0054] Further, the line LN can be generated by interpolating between the crests of the waveforms (three-dimensional waveforms or two-dimensional waveforms) indicating the frequency characteristics. In the case of extracting the line LN from the characteristic graph GF, the interpolation method of the line LN on the characteristic graph GF and the line LN extracted from the characteristic graph GF can be different. The interpolation method is, for example, the Lagrange interpolation, the spline interpolation, or the like. The more the data before the interpolation, the higher the accuracy of the interpolation, so the more the data of the wobble frequency characteristic is preferable. Further, the rotational speed of the rotation shaft (main shaft 22) at the time of wobbling is preferable to be the more the number of subdivisions (the number of steps). Therefore, the following use can also be made: the data is automatically acquired at night and the data for drawing a detailed characteristic graph GF is acquired before the next morning.

[0055] The peaks on the line LN indicate certain resonance points. For example, several of the peaks appearing on the line LN are generally referred to as dangerous speeds. Dangerous speeds are resonance points that resonate with the natural vibration frequencies caused by elastic elements. The elastic elements can be included in the main shaft 22 body (the spindle itself) or the support elements (bearings, etc.) of the main shaft 22.

[0056] In the peak groups PLC1 and PLC4 of the characteristic diagram GF, the frequencies at which the peaks on the wobble frequency characteristic appear are substantially fixed regardless of the value of the rotational frequency (main shaft rotational speed). These peak groups PLC1 and PLC4 are independent of the main shaft rotational speed (rotational frequency). It is thus understood that the peak groups PLC1 and PLC4 resonate with certain natural vibration frequencies that are stationary and do not depend on the rotation of the main shaft 22. Specifically, for example, resonance occurs with the natural vibration frequencies of the structural portions of the main shaft portion 20.

[0057] Furthermore, the peak groups PLC3 and PLC6 of the characteristic diagram GF change in such a manner that the frequencies at which the peaks on the wobble frequency characteristic appear increase as the rotational frequency (main shaft rotational speed) increases. On the other hand, the peak groups PLC2 and PLC5 change in such a manner that the frequencies at which the peaks on the wobble frequency characteristic appear decrease as the rotational frequency (main shaft rotational speed) increases. It is understood that these peak groups PLC2, PLC3, PLC5, and PLC6 resonate with the natural vibration frequencies caused by certain elastic elements. Specifically, for example, resonance occurs with the natural vibration frequencies of the bending mode caused by the elasticity of the shaft.

[0058] The points P1 to P6 on the line LN at which each of the peak groups PLC1 to PLC6 intersects indicate that the main shaft rotational speed coincides with the natural vibration frequency. The natural vibration frequency at each of the points P1 to P6 is excited by the rotation of the main shaft 22, and resonance occurs. That is, it is indicated that the vibration during rotation of the main shaft 22 increases in the vicinity of these points P1 to P6. Conversely, the range WP in which the vibration state (amplitude, speed, acceleration, noise, etc.) is below a prescribed threshold in the rotational frequency region between the points P1 to P6, which are remote from each other, is a rotational speed region in which the vibration is smaller than before and after, and is a range of main shaft rotational speed that is suitable for machining.

[0059] The display control portion 82 can cause the range WP of main shaft rotational speed that is suitable for machining to be displayed, or can cause the range WP of main shaft rotational speed that is suitable for machining to be displayed in accordance with a threshold value that is set in advance.

[0060] Next, a vibration diagnosis assistance method that assists in the diagnosis of vibration will be described, and the flow of the vibration diagnosis assistance processing of the vibration diagnosis assistance device 50 will be described (refer to FIG. 6). Figure 5 ).

[0061] For example, in a case where a measurement start command is received from the input device 52, the vibration diagnosis assistance process shifts to step SI. In step SI, the rotation command signal sending section 72 sends a rotation command signal RS indicating a set spindle rotational speed to the spindle control section 74. The spindle control section 74 controls the spindle motor 24 of the spindle section 20 in accordance with the rotation command signal RS, and causes the spindle 22 to rotate. When the spindle 22 rotates in accordance with the rotation command signal RS, the vibration diagnosis assistance process shifts to step S2.

[0062] In step S2, the swing command signal sending section 76 sends a swing command signal SS to the mechanism control section 78. The mechanism control section 78 controls the servo motor 32 of the movable mechanism 30 in accordance with the swing command signal SS, and causes the movable mechanism 30 to swing. When the movable mechanism 30 swings in accordance with the swing command signal SS, the vibration diagnosis assistance process shifts to step S3.

[0063] In step S3, the acquisition section 80 acquires a swing frequency characteristic when the movable mechanism 30 swings in accordance with the swing command signal SS in a state where the spindle 22 is rotating in accordance with the rotation command signal RS. When the swing frequency characteristic is acquired, the vibration diagnosis assistance process shifts to step S4.

[0064] In step S4, the acquisition section 80 determines whether or not swing frequency characteristics corresponding to a plurality of spindle rotational speeds set in advance are acquired. Here, in a case where there is a swing frequency characteristic corresponding to a spindle rotational speed that is not acquired among the swing frequency characteristics corresponding to the plurality of spindle rotational speeds set in advance, the vibration diagnosis assistance process shifts to step S5. On the other hand, in a case where there is no swing frequency characteristic corresponding to a spindle rotational speed that is not acquired, the vibration diagnosis assistance process shifts to step S6.

[0065] In step S5, the acquisition section 80 switches the currently set spindle rotational speed to a spindle rotational speed corresponding to the swing frequency characteristic that is not acquired. When the spindle rotational speed is switched, the vibration diagnosis assistance process returns to step SI.

[0066] In step S6, the display control section 82 causes the swing frequency characteristics (gain characteristics) acquired in step S4 at each of the plurality of spindle rotational speeds to be displayed on the display device 56. When the swing frequency characteristics are displayed, the vibration diagnosis assistance process ends.

[0067] Further, the order of the above-described vibration diagnosis assistance process is an example, and can be an order other than the above-described order. For example, a waveform of a swing frequency characteristic can be added to the display device 56 each time a swing frequency characteristic of one spindle rotational speed is obtained.

[0068] The above-described embodiment can be modified as follows.

[0069] (Modified Example 1)

[0070] Figure 6 1 is a diagram showing a portion of a vibration diagnosis support device 50 according to Modification 1. Configurations equivalent to those described in the above embodiment are denoted by the same reference numerals. In Modification 1, descriptions overlapping with those in the above embodiment are omitted.

[0071] In the vibration diagnosis support device 50 of the first modification, the swing command signal sending unit 76 of the above embodiment is changed to a swing command signal sending unit 76X.

[0072] The swing command signal sending unit 76X includes a first signal sending unit 76A that sends a first swing command signal SS1 and a second signal sending unit 76B that sends a second swing command signal SS2. The first swing command signal SS1 is the same as the swing command signal SS in the above embodiment.

[0073] On the other hand, the second swing command signal SS2 is different from the swing command signal SS in the above embodiment. Figure 7 : This is a diagram showing an example of the second swing command signal SS2. The value "0" of the second swing command signal SS2 indicates the reference position. In addition, the value of the second swing command signal SS2 with a + sign (positive sign) indicates the rotation angle (displacement) of the servo motor 32 when rotating in the positive direction from the reference position. The value of the second swing command signal SS2 with a - sign (negative sign) indicates the rotation angle (displacement) of the servo motor 32 when rotating in the negative direction from the reference position. The further the value (absolute value) of the second swing command signal SS2 moves away from the reference position "0", the greater the rotation angle (displacement) of the servo motor 32 from the reference position.

[0074] The second swing command signal SS2 changes so that its frequency gradually decreases over time (chirps). "Gradually decreases" includes a continuous, smooth decrease without interruption or a step-by-step decrease over time. Alternatively, the second swing command signal SS2 may change so that its frequency gradually decreases over time within a predetermined frequency range.

[0075] The oscillation frequency of the servo motor 32 (movable mechanism 30) in response to the second oscillation command signal SS2 decreases over time. Furthermore, the amplitude of the second oscillation command signal SS2 can be fixed and not change over time. When the amplitude is fixed and not change over time, the rotation angle (displacement) of the servo motor 32 when it rotates (displaces) in the forward direction from the reference position is the same as the rotation angle (displacement) of the servo motor 32 when it rotates (displaces) in the reverse direction from the reference position.

[0076] The second swing command signal SS2 (reference Figure 7 ) and the first swing command signal SS1 (referenceFigure 3 )preferably in the correspondence relation to the object and the image reflected in the plane mirror. That is, the second swing command signal SS2 has a symmetrical relation to the first swing command signal SS1. The time change (t0→t1) of the first swing command signal SS1 is reversed to obtain (t1→t0), which is the second swing command signal SS2. Further, the second swing command signal SS2 is input to the servo motor 32 in the direction of t1→t0.

[0077] The swing command signal sending section 76X sends the first swing command signal SS1 to the mechanism control section 78 and the acquisition section 80. When the sending of the first swing command signal SS1 by the swing command signal sending section 76X is completed, the second swing command signal SS2 is sent to the mechanism control section 78 and the acquisition section 80. Alternatively, the swing command signal sending section 76X can send the first swing command signal SS1 to the mechanism control section 78 and the acquisition section 80 after sending the second swing command signal SS2 to the mechanism control section 78 and the acquisition section 80. Further, the swing command signal sending section 76 of the above-described embodiment can send the swing command signal SS and the second swing command signal SS2 to the mechanism control section 78 and the acquisition section 80.

[0078] The acquisition section 80 acquires, for each of the plurality of spindle rotational speeds set in advance, a swing frequency characteristic (first swing frequency characteristic) when the movable mechanism 30 is swung as an excitation source in accordance with the first swing command signal SS1 in a state where the spindle 22 is rotating in accordance with the rotational command signal RS. Further, the acquisition section 80 acquires, for each of the plurality of spindle rotational speeds set in advance, a swing frequency characteristic (second swing frequency characteristic) when the movable mechanism 30 is swung as an excitation source in accordance with the second swing command signal SS2 in a state where the spindle 22 is rotating in accordance with the rotational command signal RS. The display control section 82 causes the first swing frequency characteristic and the second swing frequency characteristic acquired by the acquisition section 80 to be displayed on the display device 56 (see FIG. 1) (refer to FIG. 6). Figure 2

[0079] Here, for example, when there is an abnormality such as looseness of a bolt of the servo motor 32 or the power transmission section 34, there is a tendency that the first swing frequency characteristic and the second swing frequency characteristic differ. The "abnormality" in this case becomes apparent in a case where the abnormality is of a "not sensitive region element" in control theory.

[0080] The reason for this is that the vibration generated in a case where the machine tool main body 12 is swung in a manner that the swing frequency increases with the passage of time is likely to be different from the vibration generated in a case where the machine tool main body 12 is swung in a manner that the swing frequency decreases with the passage of time.

[0081] ​Thus, compared to the case of the above embodiment in which only the swing frequency characteristic that swings in a manner in which the swing frequency increases as time passes is displayed, a more detailed vibration factor can be presented to the operator.

[0082] (Modified Example 2)

[0083] In the above embodiment, the display control section 82 causes the characteristic diagram GF to be displayed on the display device 56. The display control section 82 can also cause the spindle speed recommended at the time of processing to be displayed in addition to this display. Thereby, the rotation frequency that is quieter and stably rotated, and that is as far as possible from the resonance frequency, can be presented to the operator in a manner that is visually or intuitively easy to understand.

[0084] (Modified Example 3)

[0085] The machine tool main body 12 of the above embodiment is equipped with the movable mechanism 30 for moving one axis. However, the machine tool main body 12 can also be equipped with a plurality of movable mechanisms 30 for moving a plurality of axes. In this case, the movable mechanism 30 for moving the X-axis, the movable mechanism 30 for moving the Y-axis, and the movable mechanism 30 for moving the Z-axis can be included.

[0086] In the case where a plurality of movable mechanisms 30 are equipped on the machine tool main body 12, the vibration diagnosis assistance device 50 can be provided to the plurality of movable mechanisms 30 in a shared manner, or one vibration diagnosis assistance device 50 can be provided to each of the plurality of movable mechanisms 30.

[0087] In addition, in the case where a plurality of movable mechanisms 30 are equipped on the machine tool main body 12, the swing frequency characteristic (gain characteristic) is acquired with respect to the servo motor 32 possessed by each of the plurality of movable mechanisms 30. In this case, the vibration characteristic of the machine tool main body 12 can be captured in more detail, so the movable mechanism 30 that is closest to the abnormality site can be made to stand out clearly.

[0088] (Modified Example 4)

[0089] Figure 8 A diagram that represents a part of the vibration diagnosis assistance device 50 of Modified Example 4. In addition, the same symbol is affixed to the same constituent as that explained in the above embodiment. The explanation that is repeated in the above embodiment is omitted in Modified Example 4.

[0090] The vibration diagnosis assistance device 50 of Modified Example 4 is newly provided with an inference section 84 in addition to the above embodiment.

[0091] The inference section 84 is inputted an abnormal vibration frequency from the input device 52 according to the operation of the operator. The abnormal vibration frequency is a vibration frequency that is measured to be larger than a prescribed threshold value using a known measurement method.

[0092] The inference unit 84 infers the origin (main cause) of the abnormal vibration frequency from the wobble frequency characteristic acquired by the acquisition unit 80. The inference unit 84 infers whether the abnormal vibration frequency is derived from the stationary system in the spindle unit 20 or from the rotating system, from the wobble frequency characteristic acquired by the acquisition unit 80, in a case where the abnormal vibration frequency is input from the input device 52.

[0093] As described above, the frequency of the wave peak group PLC1, PLC4 in which the frequency at which the wave peak of the wobble frequency characteristic appears is substantially fixed regardless of the spindle rotational speed resonates with certain natural vibration frequencies that are stationary. Therefore, if the difference between the frequency indicating the wave peak and the abnormal vibration frequency is within the allowable range regardless of the spindle rotational speed, it is highly likely that the abnormal vibration frequency is derived from the stationary system.

[0094] On the other hand, as described above, the frequency of the wave peak group PLC2, PLC3, PLC5, PLC6 in which the frequency at which the wave peak of the wobble frequency characteristic appears changes with the change in the spindle rotational speed resonates with certain natural vibration frequencies caused by elastic elements that are linked to rotation. Therefore, if the difference between the frequency indicating the wave peak and the abnormal vibration frequency changes according to the spindle rotational speed, it is highly likely that the abnormal vibration frequency is derived from the rotating system.

[0095] That is, in a case where the abnormal vibration frequency is input within the first range, the inference unit 84 infers that the abnormal vibration frequency is derived from the stationary system. The first range is a range of ± centered on the frequency at which the frequency of the wave peak of the wobble frequency characteristic is fixed regardless of the spindle rotational speed. On the other hand, in a case where the abnormal vibration frequency is input within the second range, the inference unit 84 infers that the abnormal vibration frequency is derived from the rotating system. The second range is the range of the increase / decrease amplitude at which the frequency of the wave peak of the wobble frequency characteristic changes according to the increase in the spindle rotational speed.

[0096] In a case where the inference of the origin of the abnormal vibration frequency has ended, the inference unit 84 sends the inference result to the display control unit 82. In this case, the display control unit 82 causes the inference result of the inference unit 84 to be displayed on the display device 56. Thereby, it is possible to present the inference result of the cause of the abnormal vibration.

[0097] (Variation 5)

[0098] In the above-described embodiment, the spindle control unit 74 rotates the spindle 22 by means of electricity, but the spindle 22 can be rotated by means of fluid. Further, the fluid is, for example, compressed air or the like.

[0099] (Variation 6)

[0100] It is also possible to only depict the lines LN of the characteristic diagram GF. As a method for simply depicting only the lines LN, it is possible to depict the lines LN with a minimum number of components and in a short time by depicting the vibration data obtained when the movable mechanism 30 is oscillated while the spindle 22 mounted on the spindle unit 20 is rotating. In this case, the excitation source is assumed by the spindle 22 itself. In the case of only depicting the lines LN, it is possible to use the sound pressure, the vibration, the current waveform at the time of the stationary state of the other shaft, or the like, to calculate the power spectral density from the Fourier spectrum of these waveforms, and to display the power spectral density corresponding to the rotational frequency as the frequency characteristic.

[0101] (Modified example 7)

[0102] In the above embodiment, the carrying line TL is a first-order mode (rotational frequency of the spindle = oscillation frequency). Actual resonance occurs also at a frequency that is n times (n is a natural number) the rotational frequency. Thus, it is desirable to also depict the carrying line TL of the slope with respect to the rotational frequency that is n times (n is a natural number) in the characteristic diagram GF. In the case where these carrying lines TL (carrying surfaces) intersect the lines LN depicted when the peak groups PLC1 to PLC6 are acquired, the lines LN are likely to be n-order resonance points. For example, in the case where the machine tool 10 is a machining center and the tool mounted on the spindle 22 is a double-end vertical milling cutter, the spindle 22 is excited at a frequency that is twice the spindle speed. In this case, the lines LN depicted in the case where the second-order carrying line TL (carrying surface) intersects the peak groups PLC1 to PLC6 are resonance points, so it is necessary to select the spindle speed in such a manner as to avoid this. In this way, not only the first-order carrying line TL, but also the lines LN depicted in the case where the high-order carrying line TL (carrying surface) intersects are effectively utilized, so all of the peak groups PLC1 to PLC6 depicted in the characteristic diagram GF are used as useful sources of information.

[0103] (Modified example 8)

[0104] In the above embodiment, the acquisition unit 80 acquires the oscillation frequency characteristic when the movable mechanism 30 is oscillated at each of a plurality of rotational speeds that are set in advance, in a state where the spindle 22 mounted on the spindle unit 20 is rotating. The spindle 22 is only an example, and a rotational shaft other than the spindle 22 can also be used. For example, in the case where the machine tool 10 has a rotatable table, it is also possible to use a rotational shaft mounted on the table. That is, as long as it is a rotational shaft on the machine tool 10, it can be any rotational shaft. The reason for this is that, by the acquisition unit 80 acquiring the oscillation frequency characteristic when the movable mechanism 30 is oscillated at each of a plurality of rotational speeds that are set in advance, in a state where the rotational shaft mounted on the rotational shaft unit is rotating, the same effects as in the above embodiment can be obtained.

[0105] Hereinafter, the invention that can be grasped according to the above embodiment and the modified examples will be described.

[0106] (First invention)

[0107] The first invention is a vibration diagnosis assisting device (50) that assists in diagnosis of vibration of a rotating shaft portion (for example, a spindle portion (20)) of a machine tool (10) having a numerical control device. The vibration diagnosis assisting device includes: a movable mechanism (30) mounted on the machine tool; a mechanism control portion (78) that drives the movable mechanism; a swing command signal sending portion (76, 76X) that sends a first swing command signal (SS1) or a second swing command signal (SS2) to the mechanism control portion, the first swing command signal (SS1) being varied in such a manner that the frequency increases with the passage of time, and the second swing command signal (SS2) being varied in such a manner that the frequency decreases with the passage of time; a rotating shaft control portion (for example, a spindle control portion (74)) that rotates a rotating shaft (for example, a spindle (22)) mounted on the rotating shaft portion; a rotation command signal sending portion (72) that sends a rotation command signal (RS) to the rotating shaft control portion; an acquisition portion (80) that acquires a swing frequency characteristic of the rotating shaft when the movable mechanism is swung by the first swing command signal or the second swing command signal in a state in which the rotating shaft is rotating in accordance with the rotation command signal, for each of a plurality of rotational speeds that are set in advance; and a display control portion (82) that causes the swing frequency characteristic acquired by the acquisition portion to be displayed on a display device (56).

[0108] Thus, the rotational speed (rotation frequency) at which resonance is likely to occur when the movable mechanism is swung can be exhibited, and as a result, the detailed frequency characteristic of the rotating shaft portion that takes into account the natural vibration frequency unique to the rotating shaft can be captured.

[0109] The acquisition portion can acquire a first swing frequency characteristic when the movable mechanism is swung by the first swing command signal in a state in which the rotating shaft is rotating in accordance with the rotation command signal, and a second swing frequency characteristic when the movable mechanism is swung by the second swing command signal in a state in which the rotating shaft is rotating in accordance with the rotation command signal, the first swing command signal being a signal that is varied in such a manner that the frequency gradually increases with the passage of time within a predetermined frequency range, and the second swing command signal being a signal that is varied in such a manner that the frequency gradually decreases with the passage of time within the predetermined frequency range. Thus, the rotational speed (rotation frequency) at which resonance is likely to occur when the movable mechanism is swung can be exhibited more accurately and in more detail.

[0110] The amplitudes of the first swing command signal and the second swing command signal can be fixed. Thus, the swing frequency characteristic in the case where the movable mechanism is swung in a manner in which the amplitude is fixed can be acquired.

[0111] The rotating shaft portion can be mounted on the movable mechanism. Thus, compared to the case where the rotating shaft portion is not mounted on the movable mechanism, the rotational speed (rotation frequency) at which resonance is likely to occur when the movable mechanism is swung can be acquired in more detail.

[0112] Also, the rotation axis control section can rotate the rotation axis by electricity or fluid. Thus, the rotation axis can be easily rotated smoothly.

[0113] Also, the swing frequency characteristic can be a frequency characteristic of any one of an amplitude, a speed, an acceleration, and a noise sound pressure when the movable mechanism swings. Thus, a rotation speed (a rotation frequency) at which resonance is likely to occur when the movable mechanism swings can be exhibited in detail.

[0114] Also, the display control section can display the swing frequency characteristic of each rotation speed of the rotation axis on a characteristic graph (GF) in which the first axis is set as a rotation speed of the rotation axis, the second axis is set as a swing frequency, and the third axis is set as a quantity indicating a magnitude of vibration. Thus, the swing frequency characteristic can be exhibited in an easily understandable manner compared with a case in which the first axis is set as a rotation speed of the rotation axis and the second axis is set as a swing frequency on the characteristic graph. In addition, the measurement data is preferably displayed by smoothly interpolating between the measurement data. Interpolation methods include, for example, Lagrange interpolation or spline interpolation. The more data of the swing frequency characteristic that is used as a basis, the higher the accuracy, so according to the present mode, it is preferable to acquire the swing frequency characteristic at more rotation speeds. For example, a program that automatically executes the content of the operation can be used to automatically acquire data for drawing a detailed characteristic graph in an unmanned manner. In particular, this operation can be performed using time during which the machine tool is not operated, such as at night or on holidays, so that a more detailed and accurate characteristic graph is acquired. Figure 5

[0115] Also, the display control section can display a range (WP) of rotation speeds of the rotation axis that is suitable for machining according to a threshold value that is set in advance. Thus, for inexperienced and unskilled operators, it is also possible to easily select a rotation speed region of the rotation axis that is suitable for machining.

[0116] Also, the display control section can display a range of rotation speeds of the rotation axis that is suitable for machining. Thus, it is possible to easily select a rotation speed of the rotation axis that is suitable for machining.

[0117] Also, the rotation axis section can be a spindle section mounted on a machine tool, the rotation axis can be a spindle mounted on the machine tool and controlled by a numerical control device, and the movable mechanism can be a mechanism mounted on the machine tool and controlled by the numerical control device to act along a movable axis. Thus, a machined surface with high accuracy can be obtained.

[0118] (2nd Invention)

[0119] The 2nd invention is a machine tool that includes the above-described vibration diagnosis assistance device, at least one of a rotation axis section and a spindle section, and at least one movable mechanism.

[0120] ​With the above-described vibration diagnosis assistance device, a rotational speed (rotational frequency) at which resonance is likely to occur when the movable mechanism is swung can be exhibited, and as a result, the frequency characteristics of the rotational shaft portion considering the natural vibration frequency unique to the rotational shaft can be captured.

[0121] (3rd Invention)

[0122] The 3rd invention is a vibration diagnosis assistance method that assists in the diagnosis of vibration of a rotational shaft portion (for example, a spindle portion) of a machine tool. The vibration diagnosis assistance method includes: a rotation step (S1) of rotating a rotational shaft (for example, a spindle) mounted on the rotational shaft portion in accordance with a rotation command signal; a swing step (S2) of swinging a movable mechanism of the machine tool in accordance with a first swing command signal or a second swing command signal, the first swing command signal being varied so as to increase in frequency over time, and the second swing command signal being varied so as to decrease in frequency over time; an acquisition step (S3) of acquiring, for each of a plurality of rotational speeds predetermined in advance, a swing frequency characteristic when the movable mechanism is swung in accordance with the first swing command signal or the second swing command signal in a state in which the rotational shaft is rotating in accordance with the rotation command signal; and a display control step (S6) of causing the swing frequency characteristic acquired in the acquisition step to be displayed on a display device.

[0123] With this, a rotational speed (rotational frequency) at which resonance is likely to occur when the movable mechanism is swung can be exhibited, and as a result, the frequency characteristics of the rotational shaft portion considering the resonance frequency unique to the rotational shaft can be captured.

[0124] Also, the rotational shaft portion can be a spindle portion mounted on the machine tool, the rotational shaft can be a spindle mounted on the machine tool and controlled by a numerical control device, and the movable mechanism can be a mechanism that moves along a movable shaft and is mounted on the machine tool and controlled by the numerical control device. With this, a high-precision machined surface can be obtained.

Claims

1. A vibration diagnosis assisting device for assisting in diagnosing vibration of a rotating shaft portion of a machine tool having a numerical control device, characterized in that: have: a movable mechanism, which is mounted on the machine tool; a mechanism control unit that drives the movable mechanism; a swing command signal sending unit that sends a first swing command signal or a second swing command signal to the mechanism control unit, wherein the first swing command signal changes in a manner that increases in frequency over time, and the second swing command signal changes in a manner that decreases in frequency over time; a rotating shaft control unit that rotates a rotating shaft mounted on the rotating shaft unit; a rotation instruction signal sending unit, which sends a rotation instruction signal to the shaft control unit; an acquisition unit that acquires, for each of a plurality of predetermined rotational speeds, an oscillation frequency characteristic of the rotating shaft when the movable mechanism oscillates in accordance with the first oscillation instruction signal or the second oscillation instruction signal while the rotating shaft is rotating in accordance with the rotation instruction signal; and A display control unit displays the oscillation frequency characteristic acquired by the acquisition unit on a display device.

2. The vibration diagnosis assisting device according to claim 1, wherein: The acquisition unit acquires a first oscillation frequency characteristic when the movable mechanism oscillates according to the first oscillation command signal while the rotating shaft is rotating according to the rotation command signal, and a second oscillation frequency characteristic when the movable mechanism oscillates according to the second oscillation command signal while the rotating shaft is rotating according to the rotation command signal. The first swing command signal is a signal that changes in frequency gradually increasing over time within a predetermined frequency range, and the second swing command signal is a signal that changes in frequency gradually decreasing over time within a predetermined frequency range.

3. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The amplitudes of the first swing command signal and the second swing command signal are fixed.

4. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The rotating shaft portion is mounted on the movable mechanism.

5. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The rotating shaft control unit rotates the rotating shaft by means of electricity or fluid.

6. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The oscillation frequency characteristic is a frequency characteristic of any one of amplitude, velocity, acceleration, and sound pressure of noise when the movable mechanism oscillates.

7. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The display control unit displays the swing frequency characteristic for each rotation speed of the rotating shaft on a characteristic graph in which a first axis represents the rotation speed of the rotating shaft, a second axis represents the swing frequency, and a third axis represents the amount indicating the magnitude of vibration.

8. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The display control unit displays a range of the rotation speed of the rotating shaft suitable for machining based on a preset threshold value.

9. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The display control unit displays a range of the rotation speed of the rotating shaft suitable for machining.

10. The vibration diagnosis assisting device according to claim 1 or 2, wherein: The rotating shaft portion is a main shaft portion mounted on the machine tool, the rotating shaft is a main shaft mounted on the machine tool and controlled by the numerical control device, and the movable mechanism is a mechanism mounted on the machine tool and controlled by the numerical control device to move along a movable axis.

11. A machine tool, characterized in that: The vibration diagnosis supporting device according to claim 1 or 2 is provided; at least one of the rotation shaft portion and the main shaft portion; and at least one of the movable mechanisms.

12. A vibration diagnosis assisting method for assisting in the diagnosis of vibration of a rotating shaft of a machine tool, characterized in that: Include: a rotating step of rotating the rotating shaft mounted on the rotating shaft portion according to a rotation instruction signal; a swinging step of swinging the movable mechanism of the machine tool in accordance with a first swing command signal or a second swing command signal, wherein the first swing command signal changes in a manner that the frequency increases with the passage of time, and the second swing command signal changes in a manner that the frequency decreases with the passage of time; an acquisition step of acquiring, at each of a plurality of predetermined rotational speeds, a swing frequency characteristic when the movable mechanism swings in accordance with the first swing command signal or the second swing command signal while the rotating shaft is rotating in accordance with the rotation command signal; and A display control step causes the swing frequency characteristic acquired in the acquisition step to be displayed on a display device.

13. The vibration diagnosis assisting method according to claim 12, wherein: The rotating shaft portion is a main shaft portion mounted on the machine tool, the rotating shaft is a main shaft mounted on the machine tool and controlled by a numerical control device, and the movable mechanism is a mechanism mounted on the machine tool and controlled by the numerical control device to move along a movable axis.

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