JP2022114886A - Surface property estimation system - Google Patents

Abstract

To provide a surface property estimation system which estimates surface property of a workpiece quickly and highly accurately in an inprocess of grinding work.SOLUTION: A surface property estimation system H is provided with a surface property generation device 20 and a detection device 30. The surface property generation device 20 calculates whetstone surface unevenness P and a workpiece reference radius R forming surface property due to a whetstone on the basis of first basic data D1 detected spirally and second basic data D2 detected at the same position in an axial direction. The surface property generation device 20 calculates low frequency center-to-center relative vibration waveform and high frequency center-to-center relative vibration waveform forming the surface property due to center-to-center relative vibration on the basis of the second basic data D2. The surface property generation device 20 generates the surface property of a workpiece W by adding the whetstone surface unevenness P and the workpiece reference radius R, and the low frequency center-to-center relative vibration waveform and the high frequency center-to-center relative vibration waveform.SELECTED DRAWING: Figure 8

Description

The present invention relates to a surface texture estimation system.

Grinding is performed, for example, by bringing a tool rotating at high speed into contact with a rotating workpiece. When chattering vibration occurs when rotating a tool to machine a workpiece, the precision of the machined surface may deteriorate and an excessive load may be applied to the tool. Conventionally, a technique has been used to detect the occurrence of chatter vibration during machining by checking the surface condition of the workpiece after grinding. The surface condition of the workpiece is measured by a roundness measuring instrument after finishing the grinding process. Since the grinding device and the surface condition measuring instrument are separated, even if chatter vibration is detected on the surface of the workpiece, there is a problem that there is a time lag in feeding this back to the machining conditions. .

On the other hand, as in Patent Document 1, a method of detecting the occurrence of chatter vibration in-process has also been proposed. The chatter vibration detector measures, for example, the vibration acceleration, vibration displacement, etc. of the grinding device or the workpiece, and determines that chatter vibration has occurred when vibration exceeding a predetermined threshold is detected. By generating the chatter vibration on the grinding apparatus, when the chatter vibration is detected, the machining conditions can be changed to suppress the chatter vibration.

JP-A-2000-233368

With the chattering detection method of Patent Document 1, the presence or absence of chattering can be detected. It is desirable to know the surface properties of However, it takes time to measure the surface texture of the workpiece, and it is difficult to obtain the surface texture especially in-process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface texture estimation system for estimating the surface texture of a workpiece quickly and accurately in the in-process grinding process.

The surface texture estimation system includes a detection device that outputs detection data corresponding to the surface state of a workpiece ground by a grinding wheel in a grinding machine, and a measurement position of the detection device on the surface of the workpiece at least in the circumferential direction of the workpiece. a surface texture generating device for generating the surface texture of the workpiece based on the detection data detected by the detecting device by moving relative to the workpiece, the surface texture generating device determining the measurement position on the surface of the workpiece by the workpiece. First detection data, which is detection data detected by spirally moving the workpiece in the circumferential and axial directions, and by moving the measurement position in the circumferential direction at the same position in the axial direction of the workpiece Based on the second detection data, which is the detected detection data, the surface texture due to the grinding wheel to which the surface condition on the grinding surface of the grinding wheel is transferred is calculated, and based on the second detection data, the grinding wheel and the workpiece are calculated. Calculate the surface texture caused by the relative vibration between the centers to which the vibration generated by the relative fluctuation between the centers is transferred, add the surface texture caused by the grinding wheel and the surface texture caused by the relative vibration between the centers, Generate the surface texture of an object.

According to the surface texture estimation system, in order to calculate the surface texture due to the grindstone and the surface texture due to the center-to-center relative vibration, the first detection data detected spirally and the second detection data detected at the same position in the axial direction are used. Two detection data can be used. This makes it possible to reduce the number of pieces of first detection data required to calculate the surface state of the workpiece, for example, compared to the case of using only the first detection data. It is possible to shorten the time required to generate and estimate the surface texture of . Moreover, since the surface texture of the workpiece can be generated using the first detection data and the second detection data, the surface texture of the workpiece can be generated with high accuracy even when the number of data is reduced. can be done.

It is a top view which shows the structure of a grinding apparatus. It is a figure for demonstrating a detection apparatus. It is a flowchart which shows the grinding process of a grinding apparatus. It is a figure for demonstrating the surface quality of a workpiece. It is a figure for demonstrating the surface quality by grindstone origin. It is a figure for demonstrating the surface quality by grindstone origin. FIG. 4 is a diagram for explaining surface properties caused by center-to-center relative vibration; 1 is a block diagram showing the configuration of a surface texture estimation system; FIG. It is a figure for demonstrating the detection of 1st basic data (1st detection data). It is a figure for demonstrating the detection of 2nd basic data (2nd detection data). 3 is a block diagram showing the configuration of a first data processing section of the surface texture generating device; FIG. 4 is a block diagram showing the configuration of a second data processing section of the surface texture generating device; FIG. 4 is a block diagram showing the configuration of a mapping processing unit of the surface texture generating device; FIG. It is a figure which shows the surface texture by the whetstone mapped by the mapping process part. FIG. 5 is a diagram for explaining data position correction processing by a mapping processing unit; FIG. 10 is a diagram for explaining data synthesizing processing by a mapping processing unit; It is a figure which shows the surface texture by the whetstone mapped by the mapping process part. FIG. 10 is a diagram showing a surface texture (high-frequency component) due to center-to-center relative vibration mapped by a mapping processing unit; FIG. 5 is a diagram showing surface properties (low-frequency components) due to center-to-center relative vibration mapped by a mapping processing unit; FIG. 5 is a diagram showing surface properties of a workpiece mapped by a mapping processing unit;

The surface texture estimation system H will be described below with reference to the drawings. The surface texture estimation system H includes a grinding device 10, a surface texture generation device 20, and a detection device 30, as shown in FIG. The surface texture estimation system H of this example also includes an image output device 40 . In the surface texture estimation system H of this example, the detection device 30 detects a displacement value that can be detected after or during grinding by the grinding device 10, and the surface texture generation device 20 detects the workpiece detected by the detection device 30. Using the detection data corresponding to the surface condition of W, the surface condition of the workpiece W is mapped and output. Then, the image output device 40 of this example outputs the map representing the surface texture of the workpiece W generated by the surface texture generation device 20 as an image.

Here, the detection data detected by the detection device 30 includes, for example, displacement (amplitude) obtained by converting the acceleration of vibration generated corresponding to the surface state (surface shape) of the workpiece W, vibration can be exemplified by the displacement (amplitude) of . Further, the detection device 30 can detect the detection data by directly or indirectly contacting the workpiece W, and detects the detection data without contacting the workpiece W (non-contact). It is possible. In this example, the detection device 30 detects the displacement obtained by converting the acceleration on the surface of the workpiece W, and the surface texture generation device 20 uses the detected displacement to determine the surface texture. That is, the case of generating a map will be described.

(1. Configuration of Grinding Device 10)
As shown in FIGS. 1 and 2, the grinding apparatus 10 mainly includes a bed 11, a grinding wheel 12, a grinding wheel head 13, a headstock 14, a tailstock 15, a spindle table 16, and a sizing device 17. The workpiece W rotates while being supported by the headstock 14 and the tailstock 15 at both ends in the rotation axis direction. In addition, in this example, the case where the workpiece W is columnar or cylindrical is exemplified. The grinding device 10 forms the shape of the workpiece W by bringing the grinding wheel 12 into contact with the surface (outer peripheral surface) of the rotating workpiece W and grinding it.

The grinding wheel 12 is supported on the grinding wheel base 13 so as to be rotatable about an axis parallel to the Z-axis. A wheelhead guide portion 11a is fixed on the bed 11, and a wheelhead 13 is supported by the wheelhead guide portion 11a so as to be movable in the X-axis direction. A grinding wheel rotating motor 12a controlled by a controller 18 applies rotational driving force to the grinding wheel 12, and the grinding wheel 12 rotates around the rotation axis. As the grinding wheel 13 moves in the X-axis direction, the grinding wheel 12 approaches and grinds the workpiece W spaced apart in the X-axis direction.

On the bed 11, a spindle table guide portion 11b is fixed at a position separated from the wheelhead guide portion 11a in the X-axis direction. The spindle table guide portion 11b supports the spindle table 16 so as to be movable in the Z-axis direction. A headstock 14 and a tailstock 15 are arranged on the spindle table 16 so as to face each other. Both ends of the workpiece W are rotatably supported by the headstock 14 and the tailstock 15, and rotational driving force is applied from a spindle rotation motor 14a controlled by the controller 18 to rotate.

As shown in FIG. 2, the sizing device 17, which is an outer diameter measuring device, includes a pair of probes 17a, which are contact portions that come into contact with the surface of the workpiece W, and a pair of fingers 17b that support the probes 17a. . The probe 17a is provided so as to contact the surface of the workpiece W at two points across the rotation center O of the workpiece W. As shown in FIG. The sizing device 17 detects the outer diameter of the workpiece W by converting the mechanical displacement of the probe 17a into an electrical signal. The sizing device 17 is supported by an axial movement device 17c and is movable in the axial direction of the workpiece W, that is, in the Z-axis direction. Movement of the sizing device 17 in the Z-axis direction is controlled by an axial movement control section 17d.

The detection device 30 is attached to at least one of the pair of fingers 17b of the sizing device 17 of the grinding machine 10. As shown in FIG. The detection device 30 of this example mainly includes an acceleration sensor, and detects displacement obtained by conversion based on acceleration. That is, the detecting device 30 detects the displacement generated in the finger 17b when the stylus 17a of the sizing device 17 is in contact with the surface of the workpiece W and moves relative to the workpiece W. As shown in FIG.

The grinding device 10 grinds the workpiece W through the steps shown in FIG. The grinding process is divided according to the difference in grindstone feed rate, and is performed in the order of rough grinding process St1, fine grinding process St2, fine grinding process St3, and spark-out process St4. The grindstone feed rate in each process is as follows: coarse grinding process St1>fine grinding process St2>fine grinding process St3>spark-out process St4. In the rough grinding step St1, a rough shape of the workpiece W is formed. In the subsequent fine grinding process St2 and fine grinding process St3, the surface shape of the workpiece W is adjusted while the grindstone feed rate is decreased. In the final spark-out step St4, the surface of the workpiece W is finished, and the workpiece W is completed.

Here, in the surface texture estimation system H, it is preferable to estimate the surface texture of the workpiece W after the spark-out step St4 in which grinding is completed. The surface texture estimation system H estimates the surface texture of the workpiece W in-process. It also includes after the out process St4. After the grinding of the workpiece W is completed, the surface texture estimation system H preferably estimates the surface texture S of the workpiece W, which will be described later, in a state in which the rotation of the workpiece W during grinding is maintained.

(2. Overview of surface texture generating device 20)
Next, the configuration of the surface texture generation device 20 will be described. As shown in FIG. 4, it can be said that the surface texture S of the workpiece W ground by the grinding apparatus 10 is determined by various factors. That is, the surface texture S of the workpiece W is, as indicated by the solid line and the two-dot chain line in FIG. As indicated by the dashed line, it can be said that the surface texture S2 due to the center-to-center relative vibration transferred by the vibration generated by the relative fluctuation between the grinding wheel 12 and the workpiece W, that is, between the centers, is synthesized.

In other words, the surface texture S of the workpiece W can be separated into the surface texture S1 caused by the grindstone and the surface texture S2 caused by the center-to-center relative vibration. Therefore, the surface texture S can be finally generated by generating the surface texture S1 and the surface texture S2, and finally synthesizing (adding) the surface texture S1 and the surface texture S2.

Here, as shown in FIGS. 5 and 6, the surface texture S1 caused by the grindstone is further divided into the surface texture S11 to which the grindstone surface unevenness is transferred and the surface texture S12 of the static workpiece reference radius. be able to. As shown in FIG. 7, the surface texture S2 due to center-to-center relative vibration includes low-frequency components and high-frequency components. It can be separated into a surface texture S21 due to a certain high-frequency relative vibration waveform and a surface texture S22 due to a low-frequency relative vibration waveform, which is a low-frequency component.

Therefore, the surface texture S1 is generated by synthesizing (adding) the surface textures S11 and S12, the surface texture S2 is generated by synthesizing (adding) the surface textures S21 and S22, and further, the surface textures S1, By synthesizing (adding) S2, the surface texture S can be finally generated. Further, by appropriately selecting the surface textures S1, S11, S12, S2, S21, and S22 to be synthesized, it is possible to arbitrarily generate the required surface texture S as required.

Therefore, the surface texture generation device 20 of this example acquires the displacement detected by the detection device 30 as detection data, and extracts low frequency components and high frequency components from the frequency characteristics of the acquired detection data. Then, the surface texture generating device 20 performs various data processing on the extracted low frequency component and high frequency component, and based on the results of the various data processing, surface textures S11 and S12 (that is, surface texture S1) and surface textures S21 and S22 are generated. (ie surface texture S2). Then, the surface texture generating device 20 synthesizes (adds) the maps representing the surface texture S1 and the surface texture S2 to obtain the surface texture S of the workpiece W, more specifically, the map representing the surface texture S. finally generate

(2-1. Configuration of Surface Texture Generating Device 20)
As shown in FIG. 8, the surface texture generation device 20 includes a basic data acquisition unit 21, a first data processing unit 22, a second data processing unit 23, a mapping processing unit 24 as a surface texture generation unit, Prepare.

(2-2. Basic data acquisition unit 21)
The basic data acquisition unit 21 acquires detection data (displacement) detected by the detection device 30 after or during grinding. Specifically, as shown in FIG. 8, the basic data acquisition unit 21 acquires the first detection data K1 output from the detection device 30 as the first basic data D1, and the second detection data K2 as the second basic data D1. Acquired as data D2.

Here, as shown in FIG. 9, the detection device 30 first sets the measurement position for measuring the displacement of the vibration on the surface of the workpiece W relative to the workpiece W in the circumferential and axial directions in a helical shape. is detected and output to the basic data acquisition unit 21 . That is, when acquiring the first basic data D1, the probe 17a of the sizing device 17 is brought into contact with the surface of the work W while the work W is being rotated, and the sizing device is moved by the axial movement device 17c. 17 is moved continuously in the axial direction of the workpiece W. Here, the measurement position in this example is the position where the probe 17a of the sizing device 17 contacts the surface of the workpiece W. As shown in FIG. The moving speed of the sizing device 17 in the axial direction of the workpiece W is preferably about 1 mm per one rotation of the workpiece W. It can be controlled by the section 17d.

In addition, as shown in FIG. 10, the detection device 30 moves the measurement position to the same position in the axial direction (the same position in the axial direction) on the outer peripheral surface 1 of the workpiece W without moving the measurement position spirally. The second detection data K<b>2 for the circumference is detected and output to the basic data acquisition unit 21 . That is, while the workpiece W is being rotated, the probe 17a of the sizing device 17 is brought into contact with the surface of the workpiece W, and the sizing device 17 is moved to the same position in the axial direction of the workpiece W by the axial movement device 17c. Stop at position.

The basic data acquisition unit 21 acquires the spirally detected first detection data K1 as the first basic data D1. Further, the basic data acquisition unit 21 acquires the second detection data K2 for one round acquired at the same position in the axial direction as the second basic data D2. Then, the basic data acquisition unit 21 outputs the first basic data D1 and the second basic data D2 to the first data processing unit 22 and the second data processing unit 23, respectively.

Here, the first basic data D1 and the second basic data D2 are time-series data on displacement. The first basic data D1 and the second basic data D2 are generally acquired as data with the time axis as a reference. It may be converted into reference data.

(2-3. First data processing unit 22)
The first data processing unit 22 extracts low-frequency components from the frequency characteristics of the first basic data D1 and the second basic data D2, and performs various data processing described later on the extracted low-frequency components. Therefore, as shown in FIG. 11, the first data processing unit 22 includes a low-frequency component extraction unit 221, a spiral low-frequency waveform generation unit 222, a low-frequency center-to-center relative vibration waveform generation unit 223, and a workpiece reference radius calculation unit. 224 is mainly provided.

The low-frequency component extraction unit 221 performs a fast Fourier transform (hereinafter referred to as "FFT") on the first basic data D1 acquired from the basic data acquisition unit 21, and out of the frequency characteristics of the first basic data D1, A low-frequency component D11, which is the first low-frequency component and excludes one peak/peripheral component, is extracted. The 1 peak/circumference component is a component corresponding to the rotation frequency of the workpiece W. As shown in FIG. In addition, the low-frequency component extraction unit 221 performs FTT on the second basic data D2 acquired from the basic data acquisition unit 21, and out of the frequency characteristics of the second basic data D2, the second low-frequency component and 1 peak/ A low frequency component D21 excluding the frequency component is extracted. The reason why one peak/peripheral component is excluded here is that the one peak/peripheral component may be strongly detected when, for example, the rotation axis of the workpiece W is deviated. In addition, the low-frequency component extraction unit 221 extracts the low-frequency components of the first basic data D1 and the second basic data D2 that are in the frequency range of, for example, less than 50 Hz (about 15 to 50 peaks as a waveform) as low-frequency components. do.

The spiral low-frequency waveform generator 222 performs an inverse fast Fourier transform (hereinafter referred to as “inverse FFT”) on the low-frequency component D11 of the first basic data D1 extracted by the low-frequency component extractor 221. Here, the first basic data D1 is the first detection data K1 (displacement) spirally detected along the outer peripheral surface (surface) of the workpiece W by the detection device 30 . As a result, the spiral low-frequency waveform generator 222 generates a spiral low-frequency waveform SLW representing the waveform of the low-frequency component D11 of the displacement fluctuation, ie, the vibration, of the workpiece W in the spiral direction.

The low-frequency center-to-center relative vibration waveform generator 223 performs inverse FFT on the low-frequency component D21 of the second basic data D2 extracted by the low-frequency component extractor 221 . Here, the second basic data D2 is the second detection data K2 (displacement) detected at the same axial position of the workpiece W by the detection device 30 . As a result, when the inverse FFT is performed on the low-frequency component D21 of the second basic data D2, a one-section low-frequency waveform representing the low-frequency component D21 of the displacement fluctuation, ie, the vibration, in the circumferential direction (one turn) of the workpiece W can be obtained. .

By the way, the one-section low-frequency waveform, for example, the relative position of the grinding wheel 12 and the workpiece W, which does not change greatly during grinding of one workpiece W, such as pump pulsation in the grinding device 10 and the setting accuracy of the workpiece W. It represents the relative vibration (low-frequency relative vibration between centers) generated due to the change in the center-to-center distance, and can be regarded as the same along the axial direction of the workpiece W for one workpiece W. Therefore, the low-frequency relative center-to-center vibration waveform generator 223 generates a one-section low-frequency waveform obtained by performing the inverse FFT as a low-frequency relative center-to-center vibration waveform LDV.

The workpiece reference radius calculator 224 calculates the spiral low-frequency waveform SLW generated by the spiral low-frequency waveform generator 222 and the low-frequency relative center-to-center vibration waveform LDV generated by the low-frequency relative center-to-center vibration waveform generator 223. , is used to calculate the workpiece reference radius R resulting from the transfer of the surface state of the grinding surface of the grinding wheel 12 to the outer peripheral surface of the ground workpiece W. Specifically, the workpiece reference radius calculator 224 calculates the workpiece reference radius R by subtracting the low-frequency center-to-center relative vibration waveform LDV from the spiral low-frequency waveform SLW.

Here, the low-frequency center-to-center relative vibration waveform LDV is a single-section low-frequency waveform that is assumed to be the same in the axial direction of the workpiece W, as described above. For this reason, the workpiece reference radius calculation unit 224 adds (copies) the low-frequency center-to-center relative vibration waveform LDV by the number that matches the spiral number C of the spiral low-frequency waveform SLW according to the following equation 1, A workpiece reference radius R is calculated by subtracting from the waveform SLW.
R = SLW - C x LDV ... Formula 1

(2-4. Second data processing unit 23)
The second data processing unit 23 extracts high frequency components from the frequency characteristics of the first basic data D1 and the second basic data D2, and performs various data processing described later on the extracted high frequency components. Therefore, as shown in FIG. 12, the second data processing unit 23 includes a spiral high-frequency component extraction unit 231, a one-section high-frequency component extraction unit 232, a spiral high-frequency waveform generation unit 233, a high-frequency center-to-center relative vibration waveform generation unit 234, A grindstone surface unevenness calculator 235 is mainly provided.

The spiral high-frequency component extraction unit 231 performs FFT on the first basic data D1 acquired from the basic data acquisition unit 21, and extracts the first high-frequency component from the frequency characteristics of the first basic data D1 as the spiral high-frequency component D12. Here, the first basic data D1 is the first detection data K1 (displacement) spirally detected along the outer peripheral surface of the workpiece W by the detection device 30 . In addition, the spiral high-frequency component extraction unit 231 extracts, as a high-frequency component, a frequency characteristic in a frequency range of, for example, 50 Hz or more and a frequency lower than the upper limit of detection by the detection device 30 (about 50 to 500 peaks as a waveform) as a spiral high-frequency component D12. Extract.

The one-section high-frequency component extraction unit 232 performs FFT on the second basic data D2 acquired from the basic data acquisition unit 21, and extracts high-frequency components from the frequency characteristics of the second basic data D2. Further, the 1-section high-frequency component extracting unit 232 extracts a high-frequency component obtained by excluding the grinding wheel rotation frequency component corresponding to the number of revolutions of the grinding wheel 12 from the extracted high-frequency components, i.e., the second high-frequency component, as a 1-section high-frequency component D22. The grindstone rotation frequency component described above is a frequency component composed of the grindstone rotation frequency and its harmonics.

Here, the second basic data D2 is the second detection data K2 (displacement) detected at the same axial position of the workpiece W by the detection device 30 . Accordingly, the high-frequency component extracted from the second basic data D2 corresponds to one round of the workpiece W in the circumferential direction, that is, one section of the workpiece W. As shown in FIG. The one-section high-frequency component extraction unit 232 also extracts, as high-frequency components, a frequency range of, for example, 50 Hz or more and below the upper limit frequency of detection by the detection device 30 (about 50 to 500 peaks as a waveform) as one-section high frequency components D22. do.

The spiral high-frequency waveform generating section 233 performs inverse FFT on the spiral high-frequency component D12 of the first basic data D1 extracted by the spiral high-frequency component extracting section 231 . As a result, the spiral high-frequency waveform generator 233 generates a spiral high-frequency waveform SHW representing the waveform of the spiral high-frequency component D12 of the displacement variation, ie, vibration, of the workpiece W in the spiral direction.

The high-frequency center-to-center relative vibration waveform generation unit 234 performs inverse FFT on the one-section high-frequency component D22 of the second basic data D2 extracted by the one-section high-frequency component extraction unit 232 . As a result, when the inverse FFT is performed on the one-section high-frequency component D22 obtained by excluding the grindstone rotation frequency component from the high-frequency component of the second basic data D2, the displacement fluctuation in the circumferential direction (one round) of the workpiece W, that is, the one-section high frequency of vibration A single cross section high frequency waveform representing the component D22 is obtained.

By the way, the one-section high-frequency component D22 does not include the grinding wheel rotation frequency component corresponding to the number of revolutions of the grinding wheel 12 . Therefore, the one-section high-frequency waveform affects the surface texture S of the workpiece W (more specifically, the surface texture S2 due to center-to-center relative vibration) in addition to the grinding wheel rotation frequency component corresponding to the rotation speed of the grinding wheel 12. represents vibration. Here, examples of vibrations that affect the surface texture S of the workpiece W include rotation of a servomotor that controls the movement of the wheelhead 13 and the spindle table 16, externally applied vibrations, and self-excited chatter. can be done.

Therefore, the one-section high-frequency waveform represents the relative vibration (high-frequency center-to-center relative vibration) generated due to the change in the high-frequency region of the relative position between the grinding wheel 12 and the workpiece W, that is, the center-to-center distance. Similar to the frequency waveform, it can be considered identical along the axial direction of the workpiece W for one workpiece W. Therefore, the high-frequency relative vibration waveform generator 234 generates a one-section high-frequency waveform obtained by performing the inverse FFT as a high-frequency relative vibration waveform HDV.

The grindstone surface unevenness calculator 235 uses the spiral high-frequency waveform SHW generated by the spiral high-frequency waveform generator 233 and the high-frequency relative center-to-center vibration waveform HDV generated by the high-frequency relative center-to-center vibration waveform generator 234, A grindstone surface unevenness P caused by the transfer of the surface state of the grinding surface of the grinding wheel 12 to the outer peripheral surface of the ground workpiece W is calculated. Specifically, the grindstone surface unevenness calculator 235 calculates the grindstone surface unevenness P by subtracting the high-frequency center-to-center relative vibration waveform HDV from the spiral high-frequency waveform SHW.

Here, the high-frequency center-to-center relative vibration waveform HDV is a single-section high-frequency waveform that is assumed to be the same in the axial direction of the workpiece W, as described above. For this reason, the grindstone surface unevenness calculator 235 adds (copies) the high-frequency center-to-center relative vibration waveform HDV by the number that matches the spiral number C of the spiral high-frequency waveform SHW, and subtracts it from the spiral high-frequency waveform SHW according to the following equation 2. By doing so, the grindstone surface unevenness P is calculated.
P=SHW−C×HDV …Formula 2

(2-5. Mapping processing unit 24)
The mapping processing unit 24 determines the surface textures S11, S12, S21, and S22 (see FIG. 4-7) based on the various data processing results described above by the first data processing unit 22 and the second data processing unit 23. maps M1, M2, M3, and M4 corresponding to each of . Then, the mapping processing unit 24 generates a surface texture map M representing the surface texture S of the workpiece W by synthesizing (adding) the generated maps M1, M2, M3, and M4.

As shown in FIG. 13, the mapping processing unit 24 includes a grindstone surface unevenness map generation unit 241, a workpiece reference radius map generation unit 242, a high frequency center-to-center relative vibration map generation unit 243, and a low frequency center-to-center relative vibration map generation unit. 244 and a surface texture map generator 245 are mainly provided.

The grindstone surface unevenness map generation unit 241 acquires the grindstone surface unevenness P from the second data processing unit 23 (grindstone surface unevenness calculation unit 235). Then, as shown in FIG. 14, the grindstone surface unevenness map generation unit 241 generates a map M1 representing the surface texture S11 due to the grindstone surface unevenness P caused by the grindstone.

The grindstone surface unevenness P output from the grindstone surface unevenness calculator 235 is calculated using the spiral high-frequency waveform SHW generated by the spiral high-frequency waveform generator 233, as described above. The spiral high-frequency waveform SHW is based on the spirally detected first basic data D1. For this reason, since the waveform representing the grindstone surface unevenness P continues spirally along the outer peripheral surface of the workpiece W, when generating the map M1, the waveform representing the grindstone surface unevenness P can be arbitrarily set, for example, (specifically, a multiple of the rotation period of the grindstone), and arranged in the axial direction of the workpiece W for each divided section.

In this way, when the grindstone surface unevenness P is divided into arbitrary divided sections, the grindstone surface unevenness P1 of each divided section (hereinafter referred to as "divided grindstone surface unevenness P1") is The angles are different from each other. That is, as shown in FIG. 15, the split grindstone surface irregularities P1 at adjacent axial positions correspond to positions shifted in the circumferential direction of the workpiece W from each other. Here, since the grinding wheel surface unevenness P of the workpiece W is caused by the surface condition of the grinding surface of the grinding wheel 12 , it is repeatedly seen on the surface of the workpiece W every grinding wheel rotation cycle of the grinding wheel 12 .

Therefore, the grindstone surface unevenness map generator 241 of this example regards the grindstone surface unevenness on the same circumference of the workpiece W as being periodically repeated. That is, the grindstone surface unevenness map generation unit 241 of this example produces the split grindstone surface unevenness P1 at the same angle of the workpiece W when the split grindstone surface unevenness P1 for different divided sections, that is, for different angles is arranged in the axial direction. Consider. For this reason, the grindstone surface unevenness map generation unit 241 moves each of the divided grindstone surface unevennesses P1 in the circumferential direction (the direction of the arrow in FIG. 15) and aligns them as shown in FIG. As a result, the grindstone surface unevenness map generator 241 generates a map M1 shown in FIG.

When generating the map M1 by generating the divided grindstone surface unevenness P1 by dividing the continuous grindstone surface unevenness P into divided sections, the division may be performed at a position that deviates from the period of the grindstone surface unevenness P. That is, in this case, there is a fraction in the split grindstone surface unevenness P1, and when the split grindstone surface unevenness P1 including the fraction is arranged in the axial direction of the workpiece W, the split grindstone surface unevenness P1 may not be connected well. occur.

For example, taking the unbalanced state of the grinding wheel 12 related to the grinding wheel surface unevenness P, in the axial direction of the workpiece W, in the region corresponding to the width of the grinding wheel 12, the waveform phase of the split grinding wheel surface unevenness P1 is match. That is, the corrugations of the split grindstone surface unevenness P1 at adjacent axial positions have continuity, with crests and troughs adjacent to each other in the axial direction. In reproducing such continuity when generating the map M1, the grindstone surface unevenness map generation unit 241, in order to match the waveform phases at the end points of the plurality of divided grindstone surface unevennesses P1, The relative positions in the circumferential direction are corrected, that is, the fractions are processed. The grindstone surface unevenness map generation unit 241 performs fraction processing, so that the split grindstone surface unevenness P1 at each axial position can be smoothly connected to the axial direction of the workpiece W, and the accuracy of the generated map M1 can be improved. can be improved.

The workpiece reference radius map generator 242 acquires the workpiece reference radius R from the first data processing section 22 (the workpiece reference radius calculator 224). Then, as shown in FIG. 17, the workpiece reference radius map generator 242 generates a map M2 representing the surface texture S12 based on the workpiece reference radius R caused by the grindstone.

Here, the workpiece reference radius R output from the workpiece reference radius calculator 224 is calculated using the spiral low frequency waveform SLW as described above. The spiral low-frequency waveform SLW is based on the spirally detected first basic data D1. In addition, since the waveform representing the workpiece reference radius R is a change in the workpiece radius that is continuous in the axial direction of the workpiece W, when generating the map M2, the circumferential direction of the map M1 of the grindstone surface unevenness P is It is necessary to place them in the same number as the number of placements.

For this reason, the workpiece reference radius map generator 242 copies the axially continuous workpiece reference radii R by the number arranged in the circumferential direction when the grindstone surface unevenness P is divided and rounded. Then, the workpiece reference radius map generator 242 generates a map M2 by arranging the copied workpiece reference radius R. FIG.

The high-frequency relative vibration map generator 243 acquires the high-frequency relative vibration waveform HDV from the second data processor 23 (high-frequency relative vibration waveform generator 234). Then, as shown in FIG. 18, the high-frequency relative vibration map generator 243 generates a map M3 representing the surface texture S21 by the high-frequency relative vibration waveform HDV caused by the relative center-to-center vibration. When generating the map M3, the high-frequency center-to-center relative vibration map generator 243 selects (extracts) an arbitrary divided section from a plurality of divided sections into which the grindstone surface unevenness P is divided. Then, the high-frequency center-to-center relative vibration waveform generator 234 arranges the high-frequency center-to-center relative vibration waveforms HDV corresponding to the selected (extracted) divided sections in the axial direction of the workpiece W in the same number as the maps M2. By doing so, a map M3 is generated.

The low-frequency relative center-to-center vibration map generator 244 acquires the low-frequency relative center-to-center vibration waveform LDV from the first data processor 22 (low-frequency relative center-to-center vibration waveform generator 223). Then, as shown in FIG. 19, the low-frequency relative center-to-center vibration map generator 244 generates a map M4 representing the surface texture S22 by the low-frequency relative center-to-center vibration waveform LDV caused by the center-to-center relative vibration. When generating the map M4, the low-frequency relative vibration map generation unit 244 selects the map M3 generated by the high-frequency relative vibration map generation unit 243 among a plurality of divided sections into which the grindstone surface unevenness P is divided. Select (extract) the same divided section as the divided section. Then, the low-frequency relative center-to-center vibration map generation unit 244 generates the low-frequency relative center-to-center vibration waveforms LDV corresponding to the selected (extracted) divided sections in the axial direction of the workpiece W, as many as the maps M2. A map M4 is generated by arranging only

The surface texture map generator 245 generates a surface texture map M representing the surface texture S of the workpiece W, as shown in FIG. That is, the surface texture map generation unit 245 includes the map M1 generated by the grindstone surface unevenness map generation unit 241, the map M2 generated by the workpiece reference radius map generation unit 242, and the high-frequency center-to-center relative vibration map generation unit 243. A surface texture map M representing the surface texture S of the workpiece W is generated by synthesizing (adding) the map M3 generated by the low-frequency center-to-center relative vibration map generation unit 244 and the map M4 generated by the low-frequency center-to-center relative vibration map generation unit 244 .

Here, both the map M1 generated by the grindstone surface unevenness map generator 241 and the map M2 generated by the workpiece reference radius map generator 242 are due to the grindstone. Therefore, the surface texture map generating unit 245 synthesizes (adds) only the map M1 and the map M2 as necessary to obtain a surface texture map M representing the surface texture S of the workpiece W, which is caused by the grindstone. A map (not shown) representing the surface texture S1 can be generated.

The map M3 generated by the high-frequency relative center-to-center vibration map generation unit 243 and the map M4 generated by the low-frequency relative center-to-center vibration map generation unit 244 are both caused by the center-to-center relative vibration. Therefore, the surface texture map generating unit 245 synthesizes (adds) only the map M3 and the map M4 as necessary to generate a surface texture map M representing the surface texture S of the workpiece W. A map (not shown) representing the vibration-induced surface texture S2 can be generated.

Then, the surface texture map generator 245 outputs the generated surface texture map M to the image output device 40 . Thereby, the image output device 40 displays the acquired surface texture map M as an image on a display, for example.

As can be understood from the above description, according to the surface texture estimation system H, the surface texture generation device 20 generates the spirally detected first detection data K1, that is, the first basic data D1 and at the same position in the axial direction. Based on the detected second detection data K2, that is, the second basic data D2, it is possible to calculate the grindstone surface unevenness P and the workpiece reference radius R that form the surface texture S1 caused by the grindstone. Further, the surface texture generating device 20 generates a low-frequency center-to-center center-to-center vibration-induced surface texture S2 based on the second detection data K2 detected at the same position in the axial direction, that is, the second basic data D2. A vibration waveform LDV and a high-frequency center-to-center relative vibration waveform HDV can be calculated. Then, the surface texture S of the workpiece W can be generated by adding the surface texture S1 caused by the grindstone and the surface texture S2 caused by the center-to-center relative vibration.

More specifically, the surface texture generating device 20 converts the surface texture S1 caused by the grindstone into a low-frequency component as a first low-frequency component among the frequency components of the spirally detected first basic data D1 (first detection data K1). A frequency component D11, a spiral high frequency component D12 that is the first high frequency component, and a second low frequency component of the frequency components of the second basic data D2 (second detection data K2) detected at the same position in the axial direction. It can be calculated based on the low frequency component D21 and the one-section high frequency component D22, which is the second high frequency component. Further, the surface texture generating device 20 calculates the surface texture S2 caused by the center-to-center relative vibration based on the low frequency component D21 and the one-section high frequency component D22 of the second basic data D2 (second detection data K2). can be done.

As a result, the number of data (the number of peaks in the waveform) required for calculation can be reduced in the surface texture S1 due to the grindstone calculated using the first basic data D1 and the second basic data D2. As a result, the time required to estimate the surface texture S of the workpiece W, specifically, the time required to detect (collect) the first basic data D1 (first detection data K1) can be shortened. can.

Further, when calculating the surface texture S1 due to the grindstone, the first basic data D1 (first detection data K1) detected spirally and the second basic data corresponding to the same position in the axial direction, that is, one rotation of the workpiece W Data D2 (second detection data K2) can be used. This makes it possible to improve the calculation accuracy of the surface texture S1 due to the grindstone, and as a result, it is possible to improve the estimation accuracy of the surface texture S of the workpiece W finally obtained.

Further, when the surface texture S1 due to the grindstone is calculated after machining the workpiece W, for example, the surface texture S1 can be calculated with high accuracy in a short time. Therefore, the surface texture S1 can be used for maintenance of the grinding apparatus 10, for example, determination of truing intervals and the like.

Furthermore, the surface texture S2 caused by center-to-center relative vibration can be calculated using the second basic data D2 (second detection data K2) detected at the same position in the axial direction. This makes it possible to reduce the number of data required to calculate the surface texture S2 due to center-to-center relative vibration. As a result, even while the workpiece W is being ground, it is possible to calculate the surface texture S2 due to center-to-center relative vibration. As a result, the calculated surface texture S2 due to center-to-center relative vibration can be used to monitor the grinding accuracy, the operating state of the grinding apparatus 10, and the like. , anomaly detection, etc.

(3. Other exceptions)
In the above-described example, the detection device 30 mainly includes an acceleration sensor, and detects the displacement obtained by converting the acceleration as the first detection data and the second detection data. The detection device 30 is not limited to mainly including an acceleration sensor, and may mainly include a displacement sensor for detecting displacement caused by unevenness of the surface of the workpiece W.

Examples of the displacement sensor included in the detection device 30 include the contact-type sizing device 17 and linear gauge, or non-contact-type laser sensors, optical sensors, eddy current sensors, and the like. The contact-type sizing device 17 or linear gauge has a contact member such as a probe 17a that contacts the surface of the workpiece W, and detects vibrational displacement of the contact member that occurs as the workpiece W rotates. For example, an analog output amplifier without a low-pass filter provided in the sizing device 17 or a high frequency digital output amplifier may be used so that the sizing device 17 can detect high frequency components. The non-contact laser sensor, optical sensor, and eddy current sensor are arranged so as to be non-contact with the surface of the workpiece W. Detect displacement up to the surface.

Both the vibration displacement of the contact member detected by the contact-type sensor and the displacement detected by the non-contact-type sensor are detection data (time-series data) indicating the displacement of irregularities on the surface of the workpiece. be. Therefore, even in this case, the detection data (displacement) output from the detection device 30 is time-series data, and the basic data acquisition unit 21 obtains the first detection data K1 and the second detection data output from the detection device 30. K2 are obtained as first basic data D1 and second basic data D2, respectively.

The linear gauge is equipped with a probe that contacts the workpiece W and an arm that supports the probe, and detects the displacement of the surface of the workpiece W while the probe is in contact with the rotating workpiece W. It is. In addition, the linear gauge is supported by an axial movement device similarly to the sizing device 17 and is movable in the axial direction of the workpiece W, that is, in the Z direction.

Furthermore, in this example described above, the low-frequency component extraction unit 221 of the first data processing unit 22 performs FFT, and the spiral low-frequency waveform generation unit 222 and the low-frequency relative vibration waveform generation unit 223 perform inverse FFT. I made it In addition, the spiral high-frequency component extraction unit 231 and the one-section high-frequency component extraction unit 232 of the second data processing unit 23 perform FFT, and the spiral high-frequency waveform generation unit 233 and the high-frequency relative vibration waveform generation unit 234 perform inverse FFT. made it

In order to omit performing FFT or inverse FFT in this way, it is also possible to provide a filter capable of extracting a desired frequency component in each of the above sections. Examples of filters include low-pass filters, high-pass filters, band-pass filters, Gaussian filters, and the like.

DESCRIPTION OF SYMBOLS 10... Grinding apparatus, 11... Bed, 11a... Wheel head guide part, 11b... Spindle table guide part, 12... Grinding wheel, 12a... Grinding wheel rotary motor, 13... Wheel head, 14... Headstock, 14a... Spindle rotary motor, 15 Tailstock 16 Spindle table 17 Sizing device 17a Probe 17b Finger 17c Axial movement device 17d Axial movement controller 18 Controller 20 Surface texture Generation device 21 Basic data acquisition unit 22 First data processing unit 221 Low frequency component extraction unit 222 Spiral low frequency waveform generation unit 223 Low frequency center-to-center relative vibration waveform generation unit 224 Tool Object reference radius calculation unit 23 Second data processing unit 231 Spiral high-frequency component extraction unit 232 1-section high-frequency component extraction unit 233 Spiral high-frequency waveform generation unit 234 High-frequency center-to-center relative vibration waveform generation unit 235... Grinding wheel surface unevenness calculating unit 24... Mapping processing unit 241... Grinding wheel surface unevenness map generating unit 242... Workpiece reference radius map generating unit 243... High frequency center-to-center relative vibration map generating unit 244... Low frequency center Inter-relative vibration map generator 245 Surface texture map generator 30 Detector 40 Image output device C Number of spirals K1 First detection data K2 Second detection data D1 First base Data, D11... Low frequency component, D12... Spiral high frequency component, D2... Second basic data, D21... Low frequency component, D22... 1 cross-sectional high frequency component, HDV... High frequency center-to-center relative vibration waveform, LDV... Low frequency center-to-center relative Vibration waveform, SHW... Spiral high frequency waveform, SLW... Spiral low frequency waveform, M... Surface texture map, M1, M2, M3, M4... Map, O... Rotation center, P... Grinding wheel surface unevenness, P1... Split grinding wheel surface unevenness, R: Workpiece reference radius, S: Surface texture, S1: Surface texture (due to grindstone), S2: Surface texture (due to center-to-center relative vibration), S11, S12, S21, S22: Surface texture, H: Surface texture Estimation system, W... work piece

Claims (9)

a detection device that outputs detection data according to the surface state of the workpiece ground by the grinding wheel in the grinding device;
The surface texture of the workpiece is generated based on the detection data detected by the detection device by relatively moving the measurement position of the detection device on the surface of the workpiece in at least the circumferential direction with respect to the workpiece. and a surface texture generator,
The surface texture generation device includes:
first detection data, which is the detection data detected by spirally moving the measurement position on the surface of the workpiece in the circumferential direction and the axial direction of the workpiece; Based on the second detection data, which is the detection data detected by moving in the circumferential direction at the same position in the axial direction of the grinding wheel, the surface condition due to the grinding wheel to which the surface condition on the grinding surface of the grinding wheel is transferred calculating, based on the second detection data, calculating the surface texture caused by the center-to-center relative vibration transcribed by the vibration generated by the relative center-to-center change between the grinding wheel and the workpiece;
A surface texture estimation system for generating the surface texture of the workpiece by adding the surface texture caused by the grindstone and the surface texture caused by the center-to-center relative vibration. The surface texture caused by the grindstone is
A low frequency component based on a first low frequency component that is a low frequency component of the frequency components of the first detection data, and a second low frequency component that is a low frequency component of the frequency components of the second detection data The surface texture due to the grindstone of
A first high-frequency component, which is a high-frequency component in a higher frequency region than the first low-frequency component of the frequency components of the first detection data, and the second low-frequency component of the frequency components of the second detection data. 2. The surface texture estimation system according to claim 1, further comprising a surface texture attributed to the grinding wheel of a high frequency component based on a second high frequency component obtained by excluding a grinding wheel rotation frequency component of the grinding wheel from high frequency components in a higher frequency region than the high frequency component. The surface texture caused by the center-to-center relative vibration is
a surface texture caused by the center-to-center relative vibration based on a second low-frequency component, which is a low-frequency component among the frequency components of the second detection data;
3. The surface texture caused by the center-to-center relative vibration based on a second high frequency component in a higher frequency region than the second low frequency component among the frequency components of the second detection data. Surface texture estimation system. The surface texture generation device includes:
A basic data acquisition unit that acquires the first detection data as first basic data and acquires the second detection data as second basic data;
extracting a first low-frequency component that is a low-frequency component of the frequency characteristics of the first basic data and a second low-frequency component that is a low-frequency component of the frequency characteristics of the second basic data; A reference radius of the workpiece is calculated by subtracting the second low-frequency component from one low-frequency component, and the second low-frequency component is used to determine the center-to-center relative vibration between the grinding wheel and the workpiece. a first data processing unit that calculates a certain low-frequency center-to-center relative vibration;
a first high frequency component in a higher frequency region than the first low frequency component in the frequency characteristics of the first basic data and a second in a high frequency region than the second low frequency component in the frequency characteristics of the second basic data A high-frequency component is extracted, and using the extracted second high-frequency component, a high-frequency relative vibration between the centers of the grinding wheel and the workpiece is calculated, and from the extracted first high-frequency component, a second data processing unit for calculating the grinding wheel surface unevenness obtained by transferring the surface state of the grinding surface of the grinding wheel to the surface of the workpiece by subtracting the high-frequency relative vibration between centers;
Using the reference radius of the workpiece calculated by the first data processing unit and the grindstone surface unevenness calculated by the second data processing unit, the surface texture caused by the grindstone is generated, Using the low-frequency relative center-to-center vibration calculated by one data processing unit and the high-frequency relative center-to-center vibration calculated by the second data processing unit, generating a surface texture caused by the center-to-center relative vibration,
a surface texture generation unit for generating the surface texture of the workpiece by adding the generated surface texture due to the grindstone and the generated surface texture due to the center-to-center relative vibration;
The surface texture estimation system according to any one of claims 1 to 3, comprising: The surface texture generation unit is
Each of the reference radius, the grinding wheel surface unevenness, the low-frequency relative center-to-center vibration, and the high-frequency relative center-to-center vibration of the workpiece is mapped, and the respective maps are added to determine the surface properties of the workpiece. 5. The surface texture estimation system of claim 4, which generates a map representing . The detection device is
6. The surface texture estimation system according to claim 1, wherein time-series data relating to acceleration or displacement is output as said detection data. The detection device is
The surface texture estimation system according to any one of claims 1 to 6, provided in an outer diameter measuring device for measuring the outer diameter of said workpiece in said grinding device. The first processing unit is
The first low-frequency component is extracted by excluding one peak/circumference component from the low-frequency components of the frequency characteristics of the first basic data, and the second low-frequency component is extracted from the frequency characteristics of the second basic data. 8. The surface texture estimation system according to any one of claims 1 to 7, wherein one peak/circumference component is excluded from the low frequency components of the surface texture estimation system. The surface texture estimation system according to any one of claims 1 to 8, further comprising an image output device that outputs the surface texture of the workpiece generated by the surface texture generation device as an image.

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