JP3997936B2 - Rotational accuracy measuring method and rotational accuracy measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotation accuracy measuring method and a rotation accuracy measuring device for measuring the rotation accuracy of a rotating body that rotates about an axis.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a rotational accuracy measuring device that measures rotational accuracy of a rotating body (for example, a spindle that is rotated by a motor) that is supported by a rolling bearing or a fluid bearing and rotates, time series data indicating the displacement of the rotating body is conventionally used. A large amount of displacement data was collected regardless of the rotation of the sensor, and data processing was performed on the large amount of displacement data. In this data processing, for example, fast Fourier transform (hereinafter referred to as “FFT”) is applied to displacement data (hereinafter referred to as “collected data”) obtained in a time series, whereby data indicating a frequency spectrum ( Hereinafter described as “spectral data”). Next, by removing a synchronous run-out error (RRO) from the spectrum data, an asynchronous run-out error (NRRO) corresponding to the displacement of the rotating body that is not repeated every rotation is obtained. ing.
[0003]
Patent Literature 1 discloses a ball bearing rotational accuracy inspection method and inspection apparatus that can measure the NRRO of a single ball bearing by a simple operation. Further, Patent Document 2 discloses a rotational accuracy and dynamic torque measuring device for a radial rolling bearing that allows the rotational asynchronous vibration and the dynamic torque of the radial rolling bearing to be associated with each other so as to be accurately measured. Further, Patent Document 3 discloses a rolling bearing rotational accuracy and dynamic torque measuring device that enables accurate measurement by associating the rotational asynchronous vibrations in both radial and axial directions and dynamic torque of a rolling bearing with each other. .
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-311588 [Patent Document 2]
JP 2000-155073 A [Patent Document 3]
Japanese Patent Laid-Open No. 2001-194270
[Problems to be solved by the invention]
However, in the conventional rotational accuracy measuring device, rotation unevenness of a motor or the like that rotates the rotating body has a great influence on the measurement. Further, since the collected data is time-series data collected regardless of the rotation of the rotating body, when the FFT is performed in the data processing, the collected data is smoothly set to 0 outside a predetermined interval. As shown, appropriate weighting is performed on the collected data by a window function in advance. In general, when a window function is used, the spectrum obtained by the FFT is diffused. Therefore, the use of this function also greatly affects the measurement by the conventional rotational accuracy measuring device. As described above, in the conventional measuring apparatus, since the influence of the rotation unevenness of the motor and the window function is large, it is difficult to perform high-level measurement on the rotation accuracy, that is, accurate calculation of RRO, NRRO, and roundness.
[0006]
In view of the circumstances as described above, the applicant of the present application creates block data consisting of a plurality of data blocks by dividing the time-series data into blocks divided by the rotation period of the rotating body. Based on the block data, an index indicating the rotational accuracy of the rotating body is calculated, and a rotational accuracy measuring device capable of reducing the influence of the rotation unevenness of the motor and the influence of the window function is disclosed in Japanese Patent Application Nos. 2002-018402 and 2002. Proposed in -036777.
[0007]
This rotational accuracy measuring device can correct a phase shift for each rotation due to uneven rotation of the motor, but has a problem that a phase shift within one rotation cannot be corrected.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a rotation accuracy measuring method and a rotation accuracy measuring device capable of correcting a phase shift within one rotation.
[0008]
[Means for Solving the Problems]
The rotational accuracy measuring method according to the first aspect of the present invention provides time series data consisting of sampling values of a predetermined period indicating a radial or axial displacement of a rotating body rotating about an axis for each rotation period of the rotating body. Dividing into blocks to create a plurality of data blocks, correcting the phase shift for each rotation period of the plurality of generated data blocks, and based on the plurality of data blocks corrected for the phase shift, A rotational accuracy measurement method for calculating an index indicating rotational accuracy, wherein a phase shift within a rotation period of the rotating body of the data block is detected based on a phase of a maximum point and / or a minimum point of the sampled value. Then, the detected deviation is distributed to the sampling values in a predetermined range around the maximum point and / or minimum point of the data block, and the phase deviation for each sampling value is corrected based on the allocated deviation. And features.
[0009]
The rotational accuracy measuring apparatus according to the second aspect of the invention acquires means for acquiring time-series data consisting of sampling values of a predetermined period indicating a radial or axial displacement of a rotating body rotating about an axis, and the means The time-series data is divided into blocks for each rotation cycle of the rotating body to create a plurality of data blocks, and the phase shift for each rotation cycle of the plurality of data blocks created by the device is corrected. A rotation accuracy measuring apparatus comprising: means; and means for calculating an index indicating the rotation accuracy of the rotating body based on a plurality of data blocks in which the deviation is corrected, wherein the rotation of the rotating body of the data block Detection means for detecting a phase shift within a period based on the phase of the maximum point and / or the minimum point of the sampled value, and a shift detected by the detection unit and the maximum point of the data block Or a distribution means for distributing the sampled values in a predetermined range around the minimum point, based on the deviation 該配 partial unit is allocated, characterized in that it comprises a means for correcting the deviation of the sampled values every phase.
[0010]
In the rotational accuracy measuring method according to the first invention and the rotational accuracy measuring device according to the second invention, the acquisition means includes time-series data comprising sampling values of a predetermined period indicating the radial or axial displacement of the rotating rotating body. The means for obtaining and creating the data divides the obtained time-series data into each rotation cycle of the rotating body and creates a plurality of data blocks. The correcting means corrects the phase shift for each rotation cycle of the created plurality of data blocks, and the calculating means calculates an index indicating the rotational accuracy of the rotating body based on the corrected data blocks. .
[0011]
The detection means detects and distributes the phase shift within the rotation period of the rotating body of the data block based on the phase of the maximum point and / or minimum point (both maximum point and / or minimum point) of the sampled value. The means distributes the detected deviation to a predetermined range of sampling values around the local maximum and / or local minimum of the data block. The correcting means corrects the phase shift for each sampling value based on the shift distributed by the distributing means.
As a result, the phase shift within one rotation can be corrected, and the phase shift within one rotation can be corrected while avoiding the portion where the sampling value fluctuates rapidly. It is possible to realize a rotational accuracy measuring method and a rotational accuracy measuring device that improve the speed.
[0012]
In the rotation accuracy measuring apparatus according to a third aspect of the invention, the distribution means should distribute the deviation detected by the detection means to the sampling values within the predetermined range based on the order of the sampling values in the data block. It is characterized by being.
[0013]
In this rotational accuracy measuring device, the distributing means distributes the deviation detected by the detecting means to the sampling values within a predetermined range based on the order of the sampled values in the data block, and therefore corrects the phase deviation within one rotation. In addition, the phase deviation within one rotation can be corrected by avoiding the portion where the sampled value fluctuates abruptly and according to the magnitude of the deviation for each sampled value. It is possible to realize a rotational accuracy measuring method and a rotational accuracy measuring device that improve the correction accuracy of the rotation.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof.
FIG. 1 is an explanatory view schematically showing a configuration of an embodiment of a rotational accuracy measuring device according to the present invention, and FIG. 2 is a plan view showing a state when the rotational accuracy measuring device measures a rotating body. It is. The rotational accuracy measuring device is a measuring device that measures the rotational accuracy of a rotating body 10 supported by a bearing and rotated by a motor (not shown) about a predetermined rotating shaft 11. Collecting time-series data consisting of a non-contact displacement sensor 20 for detecting the position and a sampled value indicating the displacement in the radial direction of the rotating body 10 based on the detection signal Sd of the displacement sensor 20, and sampling data as the time-series data And a data collection processing device 30 for processing.
[0015]
The displacement sensor 20 is disposed in the vicinity of the outer peripheral surface of the rotator 10, detects the distance between the outer peripheral surface and the displacement sensor 20, and outputs the detection result as a detection signal Sd indicating the radial displacement of the rotator 10. . When detecting the axial displacement of the rotator 10 and measuring the rotational accuracy of the axial displacement, the axis of the rotator 10 is located near the upper surface of the rotator 10 as shown by the broken line in FIG. A non-contact type displacement sensor 21 for detecting the displacement in the direction is arranged, and a signal output from the displacement sensor 21, that is, a signal indicating the distance between the upper surface of the rotating body 10 and the displacement sensor 21 is used as the detection signal Sd. It ’s fine.
[0016]
The data collection processing device 30 has a configuration in which a CPU 31 as a central processing unit, an input interface unit 32, a memory 33, and a display control unit 34 are connected by a bus, and a display unit 36 is connected to the display control unit 34. Yes. The detection signal Sd from the displacement sensor 20 is input to the input interface unit 32. The input interface unit 32 has an A / D converter, and the detection signal Sd is temporarily stored in the memory 33 as digital data sampled thereby (hereinafter, this digital data is described as “original data”). ). The input interface unit 32, together with the displacement sensor 20, constitutes a means for acquiring time series data representing the displacement of the rotating body 10.
[0017]
The CPU 31 sequentially executes data processing such as DC cut processing, period division processing, phase correction, rate conversion, and FFT described later on the original data by executing a predetermined program stored in the memory 33 in advance. As a result, the data collection processing device 30 includes a DC cut unit 111 (means for acquiring time-series data), a period division unit 112 (means for creating a plurality of data blocks), and a phase correction unit 113 as shown in FIG. It operates as an apparatus including (a means for correcting a phase shift), a rate conversion unit 114 and a signal processing unit 115 (a means for calculating an index).
[0018]
The DC cut unit 111 removes a direct current component from the detection signal Sd output from the displacement sensor 20, and specifically, the detection signal Sd is performed by signal processing on original data that is digital data representing the detection signal Sd. The digital data representing the signal from which the direct current component has been removed is created as sampling data Da (this signal processing is referred to as “DC cut processing”). Although the DC cut unit 111 is realized by software, a DC component cutoff circuit is provided in the input interface unit 32, thereby removing a DC component from the detection signal Sd, and then collecting data by an A / D converter. Da may be created. In this case, the DC cut unit 111 is realized as hardware and constitutes a part of the input interface unit 32.
[0019]
The period dividing unit 112 divides the collection data Da created by the DC cut unit 111 for each rotation period of the rotating body 10 and blocks it, thereby creating block data Db composed of a plurality of data blocks (this block). Processing is called “periodic division processing”). Specifically, a zero point that is a time point corresponding to Sd = 0 is obtained from the collected data Da that is digital data representing the detection signal Sd, and the collected data Da is divided for each rotation period based on the zero point. Blocked data Db is obtained. For example, in the case where the sampling data Da corresponding to the section shown in FIG. 4 in the detection signal Sd is obtained from the DC cut unit 111, based on the zero point detected from the sampling data Da, FIG. Blocked data Db composed of four data blocks Db1, Db2, Db3, Db4 as shown is obtained.
[0020]
Each of these four data blocks Db1, Db2, Db3, Db4 is described as the number of digital signal values (sampled values indicating the displacement of the rotating body 10) (hereinafter referred to as “data number”), and the number of sampling points in one rotation cycle Are normally not equal because of the rotation irregularity of the motor. For example, as shown in FIG. 6, the number of data in the data blocks Db1, Db2, Db3, and Db4 is n1 and n2, respectively. , N3 and n4. When a signal synchronized with the rotation period (for example, a signal in which one pulse appears every rotation) is output as an index pulse Sip from a drive unit (not shown) including a motor that rotates the rotating body 10, Instead of the above-described zero point detection, the period dividing process may be performed based on the index pulse Sip.
[0021]
The phase correction unit 113 corrects a phase shift for each of the data blocks Db1, Db2, Db3, and Db4 of the blocked data Db divided and blocked by the period dividing unit 112, and each data block Db1, Db2, The phase shift in Db3 and Db4 (phase shift for each sampling point) is corrected, and the corrected blocked data Dc is output. Details of the phase shift correction for each sampling point will be described later.
[0022]
The rate conversion unit 114 performs the same interpolation process (resampling and resampling) on the blocked data Dc including a plurality of data blocks whose number of data varies as described above, so that the number of data in each data block is the same. To. That is, the sampling points of each data block are made the same by rate conversion.
At this time, considering the FFT (Fast Fourier Transform) executed by the signal processing unit 115, the number of data of each data block is set to a power of two. For example, by performing rate conversion on the blocked data Db (Dc) as shown in FIG. 6, the blocked data Dd composed of data blocks whose number of data is all 2 ^m is obtained.
[0023]
The signal processing unit 115 is a means for calculating an index indicating the rotation accuracy, and calculates spectrum data by performing FFT on the blocked data Dd after rate conversion without using a window function. And based on the calculated spectrum data, RRO, NRRO, roundness, etc. are calculated | required by the method similar to the past. Indices indicating the rotational accuracy of the rotating body 10 such as RRO, NRRO, and roundness obtained in this manner are stored in the memory 33 as measurement results, and are displayed on the display control unit 34 based on other predetermined programs. The image is sent and displayed on the display unit 36 by the display control unit 34.
[0024]
The operation for correcting the phase shift (phase shift for each sampling point) in the data block (within the rotation period of the rotating body 10) in the phase correction unit 113 of such a rotation accuracy measuring apparatus will be described below. This will be described with reference to the flowchart of FIG.
First, the phase correction unit 113 detects the maximum point and the minimum point of the sampled value in each data block, and the number of sampling points E1, E2 from the head to the minimum point in each data block as illustrated in FIG. , E3, E4 and the sampling points F1, F2, F3, F4 to the maximum point (S2), and the average value is calculated, thereby calculating the average phase of each maximum point and each minimum point. (S4).
[0025]
Next, the phase correcting unit 113 calculates a phase shift between the maximum point in the data block of interest and its average phase (S4), and a phase shift between the minimum point and its average phase (S4) (S6). Then, the phase shift is distributed to each sampled value (phase) (S8).
When the phase correction unit 113 allocates the phase shift to each sampling value (S8), as shown in FIG. 9, the phase shift of the minimum point is Sp / 4 before and after the minimum point (Sp is one data). The sampling points in the block (number of sampling values) are allocated to each sampling value, and the phase shift of the maximum point is allocated to each sampling value in the range Sp / 4 before and after the maximum point. In the distribution, the sampling values are weighted according to the order N (1, 2,... Sp) from the head of the data block.
[0026]
For example, in the case where the phase shift Zs of the minimum point in the data block of interest is allocated, the shift ZN allocated to the sampling points N (= Sp / 8 to 3Sp / 8) is
It is assumed that ZN = 4N × Zs / Sp.
Similarly, when the phase shift Zd of the maximum point in the data block of interest is allocated, the shift ZN allocated to the sampling points N (= 5Sp / 8 to 7Sp / 8) is
It is assumed that ZN = 4N × Zd / Sp.
[0027]
Next, the phase correction unit 113 corrects the phase of each sampling point by subtracting the phase shift (S8) allocated to each sampling point from the phase of each sampling point (S10).
Next, if there is a data block for which the phase of each sampling point is to be corrected next (S12), the phase correcting unit 113 shifts the phase between the maximum point in the data block and its average phase (S4), and A phase shift between the minimum point and the average phase (S4) is calculated (S6), and then the phase shift is distributed to each sampled value (phase) (S8). If there is no data block whose phase should be corrected (S12), the process returns.
In the above-described embodiment, the correction is performed based on the phase shift between the local maximum point and the local minimum point. However, the correction may be performed based on the phase shift between the local maximum point and the local minimum point.
[0028]
【The invention's effect】
According to the rotational accuracy measuring method according to the first invention and the rotational accuracy measuring device according to the second invention, it is possible to correct the phase shift within one rotation and to sample the correction of the phase shift within one rotation. A rotation accuracy measurement method and a rotation accuracy measurement device that can be performed while avoiding a portion where the value fluctuates rapidly and improve the phase shift correction accuracy can be realized. In addition, the variation in the displacement of the portion where the sampling value changes rapidly is reduced.
[0029]
According to the rotation accuracy measuring apparatus according to the third aspect of the invention, the phase shift within one rotation can be corrected, and the phase shift within one rotation can be corrected while avoiding the portion where the sampling value fluctuates rapidly. In addition, it is possible to implement a rotation accuracy measuring method and a rotation accuracy measuring device that can be performed according to the amount of deviation for each sampling value, and the phase deviation correction accuracy is improved. In addition, the variation in the displacement of the portion where the sampling value changes rapidly is reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing a configuration of an embodiment of a rotational accuracy measuring apparatus according to the present invention.
FIG. 2 is a plan view showing a state when the rotational accuracy measuring apparatus according to the present invention measures a rotating body.
FIG. 3 is a block diagram showing a configuration example of a data collection processing device of the rotational accuracy measuring device according to the present invention.
FIG. 4 is an explanatory diagram showing an example of collected data of the rotational accuracy measuring device according to the present invention.
FIG. 5 is an explanatory view showing the operation of the rotation accuracy measuring apparatus according to the present invention.
FIG. 6 is an explanatory view showing the operation of the rotation accuracy measuring apparatus according to the present invention.
FIG. 7 is a flowchart showing the operation of the rotation accuracy measuring apparatus according to the present invention.
FIG. 8 is an explanatory diagram showing the operation of the rotational accuracy measuring device according to the present invention.
FIG. 9 is an explanatory view showing the operation of the rotation accuracy measuring apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Rotating body 11 Rotating shaft 20, 21 Displacement sensor 30 Data collection processing device 31 CPU
32 Input interface unit 33 Memory 36 Display unit 111 DC cut unit (means for acquiring time-series data)
112 period dividing unit 113 phase correcting unit (means for correcting phase shift)
114 Rate converter 115 Signal processor (means for calculating an index)

Claims (3)

A plurality of data blocks are created by dividing the time-series data consisting of sampling values of a predetermined period indicating the radial direction or axial direction displacement of the rotating body rotating about the axis into blocks by dividing each rotating body rotation period. Rotational accuracy measurement for correcting a phase shift for each rotation period of the plurality of created data blocks and calculating an index indicating the rotation accuracy of the rotating body based on the plurality of data blocks corrected for the phase shift A method,
A phase shift of the data block within the rotation period of the rotating body is detected based on the phase of the maximum point and / or minimum point of the sampled value, and the detected shift is detected as the maximum point of the data block and / or A method for measuring rotational accuracy, comprising: distributing to a predetermined range of sampled values before and after a minimum point, and correcting a phase shift for each sampled value based on the allocated shift. Means for acquiring time-series data comprising sampling values of a predetermined period indicating a radial direction or axial displacement of a rotating body rotating about an axis, and the time-series data acquired by the means for rotating the rotating body Means for dividing each period into blocks and creating a plurality of data blocks; means for correcting a phase shift for each rotation period of a plurality of data blocks created by the means; and a plurality of means for correcting the shift by the means A rotation accuracy measuring device comprising: means for calculating an index indicating the rotation accuracy of the rotating body based on the data block of
Detection means for detecting a phase shift within the rotation period of the rotating body of the data block based on a phase of a maximum point and / or a minimum point of the sampling value, and a shift detected by the detection means in the data block Distribution means for allocating to a predetermined range of sampled values before and after the local maximum point and / or minimum point, and means for correcting a phase shift for each sampled value based on the shift distributed by the distribution means. Rotational accuracy measuring device characterized by that. 3. The rotation accuracy measuring apparatus according to claim 2, wherein the distribution unit is configured to distribute the deviation detected by the detection unit to the sampled values in the predetermined range based on the order of the sampled values in the data block. .

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