WO2022163348A1

WO2022163348A1 - Onboard measurement system

Info

Publication number: WO2022163348A1
Application number: PCT/JP2022/000696
Authority: WO
Inventors: 祐生増田; 徹河原; 眞野々山; 慎二村上; 明齋藤
Original assignee: 株式会社ジェイテクト
Priority date: 2021-01-27
Filing date: 2022-01-12
Publication date: 2022-08-04
Also published as: CN116529023A; JP2022114895A; DE112022000851T5

Abstract

An onboard measurement system (H) comprises an onboard measurement device (20) and an output device (30). The output device (30) acquires measurement data measured as a result of the onboard measurement device (20) causing a measurement position on the surface of a workpiece (W) to move relative to the workpiece (W) in at least a circumferential direction, performs a plurality of analyses relating to processing quality of the workpiece (W) using any of a low-frequency component, a high-frequency component, and a low-frequency component and a high-frequency component from among frequency components of the measurement data, and outputs a plurality of analysis results.

Description

On-machine measurement system

This disclosure relates to an on-board measurement system.

Patent Document 1 describes an example of an automatic dimension measuring device. This automatic dimension measuring device includes a control unit that performs roundness analysis processing. Then, the control unit controls the grinding device to perform sizing processing of the workpiece based on the measurement data measured by the sizing device, and analyzes the roundness of the workpiece based on the measurement data of the sizing device. It is designed to

Japanese Patent Application Laid-Open No. 2006-153897

By the way, the automatic dimension measuring device described in Patent Document 1 only analyzes the roundness using the measurement data from the sizing device. When grinding a workpiece, it is desirable to be able to measure the shape of the workpiece, the condition of the ground surface, the operating condition of the grinding device, etc., and to be able to grasp the processing quality of the workpiece ground by the grinding device. For this reason, usually, a plurality of devices may be provided for measuring each of the shape of the workpiece, the state of the ground surface, the operating state of the grinding device, and the like. As a result, the entire system including the grinding device becomes complicated and expensive, and it may take time to obtain processing quality.

An object of the present disclosure is to provide an on-machine measurement system that can obtain the processing quality of grinding at low cost and in a short time in the in-process of grinding.

The on-machine measurement system includes an on-machine measurement device provided in the grinding machine for measuring the surface condition of the workpiece ground by the grinding wheel in the grinding machine and outputting measurement data representing the surface condition of the workpiece; The upper measuring device obtains measurement data by moving the measurement position on the surface of the workpiece relative to the workpiece at least in the circumferential direction, and obtains the low frequency component of the frequency components of the measurement data and A workpiece ground by a grinding machine using either a high-frequency component in a higher frequency range than the low-frequency component among the frequency components, or the low-frequency component and the high-frequency component among the frequency components of the measurement data. and an output device that performs a plurality of analyzes related to the processing quality of and outputs a plurality of analysis results.

According to the on-machine measurement system, the on-machine measurement device provided in the grinding machine measures the surface condition of the workpiece, and the output device acquires the low-frequency component, the high-frequency component, and the A number of analyzes relating to the machining quality of the workpiece can be performed using the measured data of either the low frequency component or the high frequency component. The output device can output a plurality of analysis results obtained by the analysis.

As a result, in the onboard measurement system, for example, only the low frequency component of the measurement data, only the high frequency component of the measurement data, or both the low frequency component and the high frequency component of the measurement data are used to output a plurality of analysis results. be able to. Further, in the on-board measurement system, for example, the first low frequency component and the second low frequency component of the measurement data, the first high frequency component and the second high frequency component of the measurement data, the first low frequency component of the measurement data A plurality of analysis results can be output by appropriately combining the low frequency component and the high frequency component such as the frequency component and the second high frequency component, or the second low frequency component and the first high frequency component of the measurement data. .

Therefore, according to the on-machine measurement system, it is possible to use an on-machine measurement device with a simple configuration for measuring the surface condition of the workpiece, so the configuration of the system can be simplified and the cost can be reduced. In addition, according to the on-board measurement system, by appropriately combining the low frequency component and the high frequency component of the measurement data measured by the on-board measurement device, when collecting and analyzing each measurement data from a plurality of measurement devices Compared to , the time required to obtain analysis results can be shortened.

FIG. 1 is a plan view showing the configuration of the grinding device. FIG. 2 is a diagram for explaining the on-board measuring device. FIG. 3 is a flow chart showing the grinding process of the grinding device. FIG. 4 is a diagram for explaining the surface properties of the workpiece. FIG. 5 is a diagram for explaining the surface properties caused by the grindstone. FIG. 6 is a diagram for explaining the surface texture caused by the grindstone. FIG. 7 is a diagram for explaining the surface texture caused by center-to-center relative vibration. FIG. 8 is a block diagram showing the configuration of the on-board measurement system. FIG. 9 is a diagram for explaining the measurement of the first measurement data. FIG. 10 is a diagram for explaining the measurement of the second measurement data. FIG. 11 is a block diagram showing the configuration of the first data analysis processing section of the output device. FIG. 12 is a block diagram showing the configuration of the second data analysis processing section of the output device. FIG. 13 is a block diagram showing the configuration of the output processing section of the output device. FIG. 14 is a diagram for explaining an analysis result regarding the shape of the workpiece by the output processing unit. 15A and 15B are diagrams for explaining analysis results regarding the machine state by the output processing unit. FIG. FIG. 16 is a diagram for explaining an analysis result (map) regarding processing quality by the output processing unit. FIG. 17 is a diagram for explaining an analysis result (map) regarding processing quality by the output processing unit. FIG. 18 is a diagram for explaining an analysis result (map) regarding processing quality by the output processing unit. FIG. 19 is a diagram for explaining an analysis result (map) regarding processing quality by the output processing unit. FIG. 20 is a diagram for explaining an analysis result (map) regarding processing quality by the output processing unit.

The on-machine measurement system H will be described below with reference to the drawings. The on-machine measurement system H includes a grinding device 10, an on-machine measurement device 20, and an output device 30, as shown in FIG. The on-machine measurement system H of this example also includes an image output device 40 .

In the on-machine measuring system H of this embodiment, the on-machine measuring device 20 measures the surface (grinding surface) of the workpiece W during or after being ground by the grinding device 10, and the output device 30 measures the on-machine measuring device 20 Various data analysis processes are performed on the basis of the measurement data measured by , and a plurality of analysis results relating to the machining quality of the workpiece W are output. The image output device 40 of this example outputs the plurality of analysis results output from the output device 30 as images.

Here, examples of measurement data detected by the on-machine measuring device 20 include vibration acceleration and vibration displacement (amplitude) generated corresponding to the surface state (surface texture) of the workpiece W. can be done. In addition, the on-machine measuring device 20 can directly or indirectly contact the workpiece W to measure the measurement data, and can also measure the measurement data without contacting the workpiece W (non-contact). It is possible to measure In this example, the case where the on-machine measuring device 20 measures the displacement on the surface of the workpiece W and the acceleration related to the displacement will be described as an example.

(1. Configuration of Grinding Device 10)
As shown in FIGS. 1 and 2, the grinding apparatus 10 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 controller 17. A measuring device 20 is provided. 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 illustrated. 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 rotatably supported on the grinding wheel base 13 around 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 17 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, the 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 17 to rotate.

(2. Configuration of on-board measuring device 20)
The on-machine measuring device 20 of this example is formed including a so-called sizing device. As shown in FIGS. 1 and 2, the on-machine measuring device 20 includes a pair of probes 21 that are contact portions that come into contact with the surface of the workpiece W, and a pair of fingers 22 that support the probes 21 . The probe 21 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 pair of fingers 22 are provided with a probe 21 at their distal end portions, and are exchangeable by detaching their proximal end portions. The on-machine measuring device 20 is supported by an axial movement device 23 and is movable in the axial direction of the workpiece W, that is, in the Z-axis direction. Movement of the on-machine measuring device 20 in the Z-axis direction is controlled by an axial movement control section 24 . The movement in the Z-axis direction is not limited to that by the axial movement device 23, and for example, it is possible to use the shift function of the main shaft and the tailstock shaft of the grinding device 10. FIG.

The on-machine measuring device 20 measures the unevenness of the outer periphery of the workpiece W as the surface condition of the workpiece W by converting the mechanical displacement of the probe 21 into an electrical signal related to the displacement and acceleration. Here, the on-machine measuring device 20 measures the outer diameter of the workpiece W, that is, the surface condition of the workpiece W, in a frequency range of less than 60 Hz, for example. That is, the on-machine measuring device 20 can measure the low-frequency component of the frequency characteristics of the surface state of the workpiece W.

The on-board measuring device 20 also has a high-frequency component measuring device 25 attached to at least one of the pair of fingers 22 . The high-frequency component measuring device 25 of this example mainly includes an acceleration sensor added by being attached to the finger 22, and among the frequency characteristics of the surface state of the workpiece W, for example, in a frequency range of 60 Hz or more, the workpiece Measure the acceleration associated with the displacement value at the W surface state. That is, the high-frequency component measuring device 25 measures the acceleration associated with the displacement (vibration) generated in the finger 22 when the probe 21 moves relative to the workpiece W while in contact with the surface of the workpiece W. It is measured as a high frequency component which is in a higher frequency region than the low frequency component in the frequency characteristic of the surface state of W. FIG.

Here, in this example, a case where an acceleration sensor is attached (added) to the finger 22 as the high-frequency component measuring device 25 is illustrated. However, the high-frequency component measuring device 25 is not limited to adding an acceleration sensor. can be used. In this case, since the on-board measuring device 20 measures displacement instead of acceleration, processing for converting acceleration to displacement, which will be described later, is not required.

(3. Grinding process of workpiece W by grinding device 10)
The grinding device 10 grinds the workpiece W through a plurality of 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 on-machine measuring system H, the on-machine measuring device 20 operates during the period from the rough grinding step St1 during grinding of the workpiece W to the spark-out step St4, or after the spark-out step St4 when grinding is completed. Preferably, the surface condition of the workpiece W is measured. Note that the on-machine measurement system H outputs a plurality of analysis results related to machining quality, which will be described later, in-process. and includes after the spark-out step St4.

(4. Outline of output device 30)
Next, an overview of the output device 30 will be described. As shown in FIG. 4, the surface texture S, which is one of the processing qualities of the workpiece W ground by the grinding device 10, is determined by various factors. That is, the surface texture S of the workpiece W includes, as indicated by the solid line and the two-dot chain line in FIG. As indicated by the dashed line, the surface texture S2 is synthesized due to the center-to-center relative vibration in which the vibration generated by the relative fluctuation between the grinding wheel 12 and the workpiece W, that is, between the centers is transferred.

Then, the surface texture S, that is, the surface texture S1 and the surface texture S2 are measured by the on-machine measuring device 20 as measurement data. Here, the measurement data measured by the on-board measuring device 20 includes the low frequency component measured by the probe 21 and the high frequency component measured by the high frequency component measuring device 25 . Therefore, it can be said that the surface texture S is determined by synthesizing the low frequency component and the high frequency component.

The surface texture S1 caused by the grindstone is the surface texture of the workpiece W in the circumferential direction and the axial direction. As shown in FIGS. A surface texture S12 with a static workpiece reference radius including components is synthesized. Here, the surface texture S11 is, for example, chatter vibration (hereinafter referred to as “chatter degree”), which is unevenness caused by the grindstone in the circumferential direction of one cross section of the workpiece W, or chatter vibration in the axial direction of the workpiece W. It reflects the machining accuracy such as the degree of variation in degree (hereinafter referred to as "scale degree").

Further, the surface texture S2 due to center-to-center relative vibration is the surface texture in the circumferential direction of one cross section of the workpiece W, and as shown in FIG. 7, low frequency components and high frequency components are synthesized. That is, the surface texture S2 is a combination of the surface texture S21, which is a high-frequency component, and the surface texture S22, which is a low-frequency component. Here, the surface texture S2 includes, for example, the shape of the workpiece W, which depends on the machining accuracy such as roundness, runout amount of the ground surface, coaxiality, vibration of the grinding device 10, and self-excited vibration during machining. , reflect machine and machining conditions such as spark-out effects.

Therefore, the output device 30 of this example extracts low frequency components and high frequency components from the measurement data measured by the on-board measurement device 20 . Then, the output device 30 performs various data analysis processes on the extracted (acquired) low-frequency component and high-frequency component, and outputs a plurality of analysis results using the various data analysis processes.

(4-1. Configuration of output device 30)
The output device 30 includes a basic data acquisition unit 31, a first data analysis processing unit 32, a second data analysis processing unit 33, and an output processing unit 34, as shown in FIG. The output device 30 has, for example, a processor and a memory storing instructions such as a program. The operations of the data analysis processing unit 33 and the output processing unit 34 may be performed.

(4-2. Basic data acquisition unit 31)
The basic data acquisition unit 31 acquires measurement data (displacement and acceleration) detected by the on-machine measuring device 20 during or after grinding. Specifically, as shown in FIG. 8, the basic data acquisition unit 31 acquires the first measurement data K1 output from the on-board measurement device 20 as the first basic data D1, and the second measurement data K2 as the first basic data D1. Obtained as two basic data D2.

Here, as shown in FIG. 9, the on-machine measuring device 20 sets measurement positions for measuring the displacement and acceleration according to the surface state of the workpiece W in the circumferential direction and the axial direction with respect to the workpiece W. The first measurement data K<b>1 in the case of relative spiral movement is detected and output to the basic data acquisition unit 31 . That is, when acquiring the first basic data D1, the probe 21 of the on-machine measuring device 20 is brought into contact with the surface of the work W while the work W is rotated, and the axial movement device 23 moves the on-machine The measuring device 20 is moved continuously in the axial direction of the workpiece W. As shown in FIG. Here, the measurement position in this example is the position where the probe 21 of the on-machine measuring device 20 contacts the surface of the workpiece W. As shown in FIG. Further, the first measurement data K1 includes the measurement data (displacement) of the low frequency component and the measurement data (acceleration) of the high frequency component measured by the high frequency component measuring device 25 .

In addition, as shown in FIG. 10, the on-machine measuring device 20 does not move the measuring position spirally, but allows the measuring position to be at the same position in the axial direction (the same position in the axial direction) or at a distance in the axial direction. The second measurement data K<b>2 for one round of the outer peripheral surface of the workpiece W when the workpiece W is moved to the target is detected and output to the basic data acquisition unit 31 . That is, while the workpiece W is rotated, the probe 21 of the on-machine measuring device 20 is brought into contact with the surface of the workpiece W, and the axial movement device 23 moves the on-machine measuring device 20 in the axial direction of the workpiece W. stop at the same position. Here, the second measurement data K2 includes low-frequency component measurement data (displacement) and high-frequency component measurement data (acceleration) measured by the high-frequency component measuring device 25 .

The basic data acquisition unit 31 acquires the spirally detected first measurement data K1 as the first basic data D1. Further, the basic data acquisition unit 31 acquires the second measurement 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 31 outputs the first basic data D1 and the second basic data D2 to the first data analysis processing unit 32 and the second data analysis processing unit 33, respectively.

Here, the first basic data D1 and the second basic data D2 are time-series data relating to displacement and acceleration. 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.

(4-3. First data analysis processing unit 32)
The first data analysis processing unit 32 extracts low-frequency components from the frequency characteristics of the first basic data D1 and the second basic data D2, and performs various data analysis processes described later on the extracted low-frequency components. Calculate a plurality of first analysis results. Therefore, as shown in FIG. 11, the first data analysis processing unit 32 includes a low-frequency component extraction unit 321, a spiral low-frequency waveform generation unit 322, a low-frequency center-to-center relative vibration waveform generation unit 323, and a workpiece reference radius calculation unit. A part 324 is mainly provided.

The low-frequency component extraction unit 321 performs a fast Fourier transform (hereinafter referred to as "FFT") on the first basic data D1 acquired from the basic data acquisition unit 31, and out of the frequency characteristics of the first basic data D1, A low frequency component D11 is extracted. In addition, the low-frequency component extraction unit 321 performs FFT on the second basic data D2 acquired from the basic data acquisition unit 31, and extracts the low-frequency component D21, which is the first analysis result, out of the frequency characteristics of the second basic data D2. Extract. Here, the low-frequency component extraction unit 321 extracts the low-frequency components of the first basic data D1 and the second basic data D2, which are in the frequency range of, for example, less than 60 Hz (about 15 to 50 peaks as a waveform) as the low-frequency components. Extract.

The spiral low-frequency waveform generator 322 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 321. Here, the first basic data D1 is the first measurement data K1 (displacement) spirally detected along the outer peripheral surface (surface) of the workpiece W by the on-machine measuring device 20 . As a result, the spiral low-frequency waveform generator 322 calculates the 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 as the first analysis result.

The low-frequency center-to-center relative vibration waveform generation unit 323 performs inverse FFT on the low-frequency component D21 of the second basic data D2 extracted by the low-frequency component extraction unit 321. Here, the second basic data D2 is the second measurement data K2 (displacement) detected at the same axial position of the workpiece W by the on-machine measuring device 20 . 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 323 calculates the one-section low-frequency waveform obtained by performing the inverse FFT as the low-frequency relative center-to-center vibration waveform LDV, which is the first analysis result.

The workpiece reference radius calculator 324 calculates the spiral low-frequency waveform SLW generated by the spiral low-frequency waveform generator 322 and the low-frequency relative center-to-center vibration waveform LDV generated by the low-frequency relative center-to-center vibration waveform generator 323. , 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 surface of the ground workpiece W. Specifically, the workpiece reference radius calculator 324 calculates the workpiece reference radius R as the first analysis result 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 calculator 324 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, and calculates the spiral low-frequency A workpiece reference radius R is calculated by subtracting from the waveform SLW.
R = SLW - C x LDV ... Formula 1

(4-4. Second data analysis processing unit 33)
The second data analysis processing unit 33 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 on the extracted high-frequency components to obtain a plurality of second data. Calculate the second analysis result. Therefore, as shown in FIG. 12, the second data analysis processing unit 33 includes a spiral high-frequency component extraction unit 331, a one-section high-frequency component extraction unit 332, a spiral high-frequency waveform generation unit 333, and a high-frequency center-to-center relative vibration waveform generation unit 334. , and a grindstone surface unevenness calculator 335 .

The spiral high-frequency component extraction unit 331 performs FFT on the first basic data D1 acquired from the basic data acquisition unit 31, and further converts the acceleration data into displacement data, thereby extracting the high-frequency component out of the frequency characteristics of the first basic data D1. A component is extracted as a spiral high frequency component D12. Here, the first basic data D1 is the first measurement data K1 (acceleration) spirally detected along the outer peripheral surface of the workpiece W by the on-machine measuring device 20 . In addition, the spiral high-frequency component extraction unit 331 extracts, as high-frequency components, frequency characteristics in a frequency range of, for example, 60 Hz or higher and lower than the upper limit frequency of detection by the on-board measuring device 20 (about 50 to 500 crests as a waveform) as spiral high-frequency components. Extract as D12.

The 1-cross-section high-frequency component extraction unit 332 performs FFT on the second basic data D2 acquired from the basic data acquisition unit 31, and further converts the acceleration data into displacement data, thereby obtaining, among the frequency characteristics of the second basic data D2, A high frequency component D22 is extracted. Further, the one-section high-frequency component extracting unit 332 extracts, from the extracted high-frequency component D22, the grinding wheel rotation frequency component fg corresponding to the number of revolutions of the grinding wheel 12 and the high-frequency component excluding its harmonics, as one-section high-frequency component D221. .

Here, the second basic data D2 is the second measurement data K2 (acceleration) detected by the on-machine measuring device 20 at the same position in the axial direction of the workpiece W. 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. In addition, the one-section high-frequency component extraction unit 332 also extracts, as high-frequency components, a frequency range of, for example, 60 Hz or higher and lower than the upper limit frequency of detection by the on-board measuring device 20 (about 50 to 500 peaks as a waveform) as high-frequency components D22. do.

The spiral high-frequency waveform generation unit 333 performs inverse FFT on the spiral high-frequency component D12 of the first basic data D1 extracted by the spiral high-frequency component extraction unit 331. As a result, the spiral high-frequency waveform generator 333 calculates a spiral high-frequency waveform SHW representing the waveform of the spiral high-frequency component D12 of the displacement fluctuation, ie, the vibration, of the workpiece W in the spiral direction as the second analysis result.

The high-frequency center-to-center relative vibration waveform generation unit 334 performs inverse FFT on the one-section high-frequency component D221 of the second basic data D2 extracted by the one-section high-frequency component extraction unit 332. As a result, when the inverse FFT is performed on the one-section high-frequency component D221 obtained by excluding the grinding wheel rotation frequency component fg and its harmonics 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, A one-section high-frequency waveform representing the one-section high-frequency component D221 of the vibration is obtained.

By the way, the one-section high-frequency component D221 does not include the grinding wheel rotation frequency component fg corresponding to the number of revolutions of the grinding wheel 12 and its harmonics. Therefore, the one-section high-frequency waveform includes the surface texture S of the workpiece W (more specifically, the surface texture S2 caused by center-to-center relative vibration) other than the grinding wheel rotation frequency component fg corresponding to the rotation speed of the grinding wheel 12 and its harmonics. represents the vibration that affects the surface texture S22) in . Here, examples of vibrations that affect the surface texture S22 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 334 calculates the one-section high-frequency waveform obtained by performing the inverse FFT as the high-frequency relative vibration waveform HDV, which is the second analysis result.

The grindstone surface unevenness calculator 335 uses the spiral high-frequency waveform SHW generated by the spiral high-frequency waveform generator 333 and the high-frequency relative center-to-center vibration waveform HDV generated by the high-frequency relative center-to-center vibration waveform generator 334, 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 335 calculates the grindstone surface unevenness P as the second analysis result 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 335 adds (copies) the high-frequency center-to-center relative vibration waveform HDV by the number that matches the number of spirals C of the spiral high-frequency waveform SHW, and subtracts it from the spiral high-frequency waveform SHW according to Equation 2 below. By doing so, the grindstone surface unevenness P is calculated.
P=SHW−C×HDV …Formula 2

(4-5. Output processing unit 34)
The output processing unit 34 outputs a plurality of analysis results using a plurality of first calculation results calculated by the first data analysis processing unit 32 and a plurality of second calculation results calculated by the second data analysis processing unit 33. It can be processed and output. A plurality of output analysis results will be described below by way of example.

A plurality of analysis results output by the output processing unit 34 are related to the processing quality of the workpiece W ground by the grinding device 10 . Examples of processing quality include the shape (processing accuracy) of the workpiece W, such as the roundness of the workpiece W, the runout amount of the ground surface, and the coaxiality of the workpiece W, which are related to the surface properties S2 described above. can be done. Also related to processing quality are the processing state of the grinding device 10 and the mechanical state of the grinding device 10 . The machining state is included in the machining accuracy, and examples include the spark-out state and the sharpness state of the grinding wheel 12 . Vibration (mechanical vibration) of the grinding device 10 can be mentioned as the mechanical state.

As for the machining quality, machining state and machine state, second measurement data K2 (second basic data D2) measured at the same position in the axial direction by the on-machine measuring device 20 during grinding of the workpiece W is an analysis result obtained using For this reason, these analysis results are output for each process in which the grinding apparatus 10 grinds the workpiece W, that is, for all workpieces W. FIG.

Also, as processing quality, the surface texture S (surface texture S1) and line roughness of the workpiece W, which are included in the processing accuracy, can be exemplified. Regarding these machining qualities (machining accuracy), the first measurement data K1 (first This is an analysis result obtained using the basic data D1) and the second measurement data K2 (second basic data D2) measured at the same position in the axial direction. Therefore, these analysis results are appropriately output after the workpiece W is ground, for example, as required.

As shown in FIG. 13, the output processing unit 34 of this example includes a shape analysis output unit 341 that outputs analysis results related to machining quality, a machining state output unit 342 that outputs analysis results related to machining state, a machine state and a map generation output unit 344 for outputting analysis results related to machining quality.

Here, the shape analysis output unit 341, the machining state output unit 342, and the machine state output unit 343 are the second measurement data K2 (second The low frequency component and high frequency component of the basic data D2) are used. On the other hand, the map generation output unit 344 outputs the low frequency component and the high frequency component of the first measurement data K1 (first basic data D1) measured in the circumferential direction and the axial direction of the workpiece W by the on-machine measuring device 20, and the workpiece The low frequency component and the high frequency component of the second measurement data K2 (second basic data D2) measured at the same position in the axial direction of are used.

The shape analysis output unit 341 acquires the low-frequency relative center-to-center vibration waveform LDV, which is the first analysis result, from the first data analysis processing unit 32 (low-frequency relative center-to-center vibration waveform generation unit 323), and performs second data analysis. A high-frequency relative vibration waveform HDV, which is the second analysis result, is acquired from the processing unit 33 (high-frequency relative vibration waveform generation unit 334). Then, the shape analysis output unit 341 synthesizes (adds) the low-frequency relative center-to-center vibration waveform LDV and the high-frequency relative center-to-center vibration waveform HDV, so that, as shown in FIG. The circularity and the runout amount of the ground surface are output as the analysis result A1. For example, when a plurality of out-of-roundnesses and deflection amounts are analyzed in the axial direction of the workpiece W, the coaxiality of the workpiece W can also be output.

In order to evaluate the grinding effect of each of the grinding steps shown in FIG. output as For this reason, the machining state output unit 342 acquires the high frequency component D22 of the second basic data D2 as the second analysis result from the second data analysis processing unit 33 (one cross-section high frequency component extraction unit 332) for each grinding process. do.

For example, when evaluating the grinding effect of the spark-out process St4, the machining state output unit 342 sets the ratio ( fg2/fg1) is output as the analysis result A2. In this case, it is evaluated that the closer the output analysis result A2 (fg2/fg1) is to "0", the higher the grinding effect of the spark-out process St4, and the closer to "1", the lower the grinding effect of the spark-out process St4. can be done.

The machine state output unit 343 acquires the low frequency component D21 of the second basic data D2 as the first analysis result from the first data analysis processing unit 32 (low frequency component extraction unit 321), and the second data analysis processing unit 33 ( A high frequency component D22 of the second basic data D2 is obtained as the second analysis result from the one-section high frequency component extraction unit 332). Then, as shown in FIG. 15, the machine state output unit 343 outputs the relationship between the frequency change and the amplitude as the analysis result A3. Here, in the graph shown in FIG. 15, the amplitude indicated by a black square and the frequency corresponding to the same amplitude indicate the vibration state caused by the grindstone, and the other amplitudes and the frequencies corresponding to the same amplitude indicate the mechanical vibration. indicates

The map generation output unit 344 generates and outputs a map representing the surface texture S (surface texture S1) of the workpiece W in the circumferential and axial directions. Therefore, the map generation output unit 344 acquires the grindstone surface unevenness P, which is the second analysis result, from the second data analysis processing unit 33 (grindstone surface unevenness calculation unit 335). Then, as shown in FIG. 16, the map generation output unit 344 generates a map M1 representing the surface texture S11 due to the whetstone surface unevenness P caused by the whetstone, and outputs it as the analysis result A4.

Also, the map generation output unit 344 acquires the workpiece reference radius R, which is the first analysis result, from the first data analysis processing unit 32 (the workpiece reference radius calculation unit 324). Then, as shown in FIG. 17, the map generation output unit 344 generates a map M2 representing the surface texture S12 based on the workpiece reference radius R caused by the grindstone, and outputs it as an analysis result A4.

Furthermore, the map generation output unit 344 synthesizes (adds) the map M1 and the map M2. As a result, the map generation output unit 344 generates a map M3 representing the surface texture S1 caused by the grindstone, as shown in FIG. 18, and outputs it as the analysis result A4.

Here, in this example, a map M3 representing the surface texture S1 caused by the grindstone is generated by synthesizing the map M1 representing the surface texture S11 and the map M2 representing the surface texture S12. However, the map generation output unit 344 can also generate a map representing the surface texture S of the workpiece W by further synthesizing the surface texture S2 caused by the center-to-center relative vibration with the generated map M3.

In this case, the map generation output unit 344 acquires the high-frequency relative center-to-center vibration waveform HDV from the second data analysis processing unit 33 (high-frequency relative center-to-center vibration waveform generation unit 334), and as shown in FIG. A map M4 representing the surface texture S21 based on the high-frequency center-to-center relative vibration waveform HDV caused by vibration is generated. Further, the map generation output unit 344 acquires the low frequency center-to-center relative vibration waveform LDV from the first data analysis processing unit 32 (low-frequency center-to-center relative vibration waveform generation unit 323), and as shown in FIG. A map M5 representing the surface texture S22 based on the low-frequency center-to-center relative vibration waveform LDV caused by the relative vibration is generated. Then, the map generation output unit 344 synthesizes (adds) the map M4 and the map M5 representing the surface texture S2 caused by the center-to-center relative vibration to the map M3 representing the surface texture S1 caused by the grindstone, thereby obtaining the final A map representing the surface texture S of the workpiece W can be generated.

Note that the map generation output unit 344 is not limited to outputting the generated maps M1-M3 (further, the generated maps M4 and M5) as the analysis result A4, and other analysis based on the generated maps M1-M5. It is also possible to output result A4. For example, the map generation/output unit 344 can output the machining accuracy represented by the degree of chatter, the degree of scale, etc. as the analysis result A4 based on the map M1 representing the surface texture S11.

Then, the output processing unit 34 outputs a plurality of analysis results to the image output device 40. Thereby, the image output device 40 displays each of the acquired analysis results on, for example, a display.

As can be understood from the above description, according to the on-machine measurement system H, the sizing device provided in the grinding apparatus 10 and the high-frequency component measuring device 25 attached to the sizing device are used to form The on-machine measuring device 20 measures the surface condition of the workpiece W, and the output device 30 acquires the first measurement data K1 (first basic data D1) from the on-machine measuring device 20. A plurality of analyzes relating to the machining quality of the workpiece W can be performed using the low frequency component and the high frequency component of the two measurement data K2 (second basic data D2).

Then, the output device 30 can output a plurality of analysis results A1-A4 obtained by the analysis. As a result, according to the on-machine measurement system H, the on-machine measurement device 20 having a simple configuration for measuring the surface state of the workpiece W can be used, so that the configuration of the system can be simplified and the cost can be reduced. . Further, according to the on-board measurement system H, by using the first measurement data K1 (first basic data D1) and the second measurement data K2 (second basic data D2) measured by the on-board measurement device 20, For example, the time required to obtain the analysis results A1-A4 can be shortened compared to collecting and analyzing measurement data from a plurality of measurement devices.

More specifically, the output device 30 detects the spiral high frequency component D12, which is the low frequency component D11 and the high frequency component of the frequency components of the spirally detected first basic data D1 (first measurement data K1), in the same axial direction. A plurality of analyzes can be performed using the low frequency component D21 and the high frequency component D22 of the frequency components of the second basic data D2 (second measurement data K2) detected at the position. Then, the output device 30 outputs an analysis result A1 related to the shape of the workpiece W, an analysis result A2 related to the machining state, and an analysis result A3 related to the machine state as a plurality of analysis results related to the machining quality. It can be output when the object W is ground. Further, after grinding, the output device 30 can map the surface texture of the workpiece W related to the machining quality and output it as an analysis result A4, if necessary.

As a result, by utilizing the analysis results A1-A4, for example, by monitoring the analysis results A1-A3, it is possible to prevent the outflow of defective workpieces W that are suddenly generated due to the inclusion of dust in the grinding device 10. can be prevented. Further, by utilizing the analysis results A1-A4, it is possible to detect an abnormality occurring in the grinding apparatus 10 at an early stage, analyze the cause of the abnormality, and take measures against the abnormality at an early stage. Furthermore, by utilizing the analysis results A1-A4, it becomes possible to optimize the maintenance of the grinding apparatus 10, for example, the truing interval, and thus the manufacturing cost of the workpiece W can be reduced.

(5. Other examples)
In the present example described above, the on-machine measuring device 20 uses the sizing device provided in the grinding device 10 . Alternatively, the on-board measuring device 20 can use a linear gauge. Also in this case, the same effects as in the present example described above can be obtained.

In the above-described example, the high-frequency component measuring device 25 of the on-board measuring device 20 mainly includes an acceleration sensor to detect acceleration as the first and second measurement data. The high-frequency component measuring device 25 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 high-frequency component measuring device 25 include a contact sizing device and linear gauge, or a non-contact laser sensor, optical sensor, eddy current sensor, and the like. A contact-type sizing device or linear gauge has a contact member such as a probe 21 that contacts the surface of the workpiece W, and detects the vibrational displacement of the contact member that occurs as the workpiece W rotates. 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 sensor and the displacement detected by the non-contact sensor are measured data (time-series data) indicating the displacement of the irregularities on the surface of the workpiece. be. Therefore, even in this case, the measurement data (displacement) output from the on-board measuring device 20 is time-series data, and the basic data acquisition unit 31 obtains the first measurement data K1 and Second measurement data 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 in the same manner as the sizing device, 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 321 of the first data analysis processing unit 32 performs FFT, and the spiral low-frequency waveform generation unit 322 and the low-frequency relative vibration waveform generation unit 323 perform inverse FFT. I tried to do it. Further, the spiral high-frequency component extraction unit 331 and the one-section high-frequency component extraction unit 332 of the second data analysis processing unit 33 perform FFT, and the spiral high-frequency waveform generation unit 333 and the high-frequency center-to-center relative vibration waveform generation unit 334 perform inverse FFT. I made it

In this way, in order to omit performing FFT or inverse FFT, 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.

This application is based on a Japanese patent application (Japanese Patent Application No. 2021-011364) filed on January 27, 2021, the contents of which are incorporated herein by reference.

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 Controller 20 On-machine measuring device 21 Probe 22 Finger 23 Axial movement device 24 Axial movement control unit 25 High frequency Component measuring device 30 Output device 31 Basic data acquisition unit 32 First data analysis processing unit 321 Low frequency component extraction unit 322 Spiral low frequency waveform generation unit 323 Low frequency center-to-center relative vibration Waveform generation unit 324 Workpiece reference radius calculation unit 33 Second data analysis processing unit 331 Spiral high-frequency component extraction unit 332 1-section high-frequency component extraction unit 333 Spiral high-frequency waveform generation unit 334 High frequency Center-to-center relative vibration waveform generation unit 335 Grindstone surface unevenness calculation unit 34 Output processing unit 341 Shape analysis output unit 342 Machining state output unit 343 Machine state output unit 344 Map generation output unit 40... Image output device, A1, A2, A3, A4... Analysis result, C... Number of spirals, K1... First measurement data, K2... Second measurement data, D1... First basic data, D11... Low frequency component, D12 ... Spiral high frequency component, D2... Second basic data, D21... Low frequency component (first analysis result), D22... High frequency component (second analysis result), D221... 1 section high frequency component, LDV... Low frequency center-to-center relative vibration Waveform (first analysis result), HDV... High frequency center-to-center relative vibration waveform (second analysis result), SLW... Spiral low frequency waveform (first analysis result), SHW... Spiral high frequency waveform (second analysis result), M1, M2, M3, M4, M5... Map, O... Center of rotation, R... Work reference radius (first analysis result), P... Grindstone surface unevenness (second analysis result), S... Surface texture, S1... (due to grindstone ) surface texture, S2... surface texture (due to center-to-center relative vibration), S11, S12, S21, S22... surface texture, H... on-machine measurement system, W... workpiece

Claims

an on-machine measuring device provided in a grinding apparatus having a grinding wheel for measuring a surface condition of a workpiece ground by the grinding wheel and outputting measurement data representing the surface condition of the workpiece;
The on-machine measuring device acquires the measurement data measured by moving the measurement position on the surface of the workpiece relative to the workpiece in at least the circumferential direction, a high frequency component in a higher frequency range than the low frequency component among the frequency components of the measurement data; and the low frequency component and the high frequency component among the frequency components of the measurement data. an output device that performs a plurality of analyzes related to the processing quality of the workpiece ground by the grinding device and outputs a plurality of analysis results;
on-machine measurement system.
The output device is
a first data analysis processing unit that calculates a plurality of first analysis results by analysis processing using the low frequency component of the measurement data;
a second data analysis processing unit that calculates a plurality of second analysis results by analysis processing using the high frequency component of the measurement data;
2. The on-board measurement system according to claim 1, further comprising an output processing unit that outputs a plurality of said analysis results using at least one of said first analysis result and said second analysis result.
The plurality of analysis results are
3. The on-machine measurement system according to claim 1, further comprising a machining accuracy relating to grinding of said workpiece by said grinding device and a machine condition relating to grinding of said grinding device.
The on-board measuring device is
The surface condition of the workpiece is measured by moving the measurement position on the surface of the workpiece in the circumferential direction at the same position in the axial direction of the workpiece, and the measurement data is output. 4. The on-board measurement system according to any one of 3.
The on-machine measurement system according to claim 4, wherein the on-machine measurement device outputs the measurement data each time the workpiece is ground by the grinding device.
The on-board measuring device further
5. The on-machine measurement system according to claim 4, wherein the surface condition of the workpiece is measured by spirally moving the measurement position in the circumferential and axial directions of the workpiece, and the measurement data is output. .
The on-board measuring device is
The on-board measurement system according to any one of claims 1 to 6, wherein the measurement data is output as time-series data.
The on-board measuring device is
The on-machine measuring system according to any one of claims 1 to 7, comprising a sizing device for measuring the outer diameter of the workpiece in the grinding device.
The on-board measuring device is
a sizing device, and a high-frequency component measuring device mounted on the sizing device for measuring the high-frequency component out of the frequency components of the surface state of the workpiece,
measuring the low frequency component out of the frequency components of the surface state of the workpiece using the sizing device;
9. The on-machine measurement system according to claim 8, wherein the high frequency component of the frequency components of the surface condition of the workpiece is measured using the high frequency component measuring device.