JP3688145B2 - Use limit judgment device of superabrasive grinding wheel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a superabrasive grinding wheel capable of confirming a use limit due to consumption of an abrasive layer of the grindstone without stopping the rotation of the grindstone, and a use limit judging apparatus using the same.
[0002]
[Prior art]
Super abrasive grains such as CBN abrasive grains or diamond abrasive grains are several thousand times more expensive than general abrasive grains such as fused alumina abrasive grains. For this reason, when superabrasive grains are used in a grinding wheel, a superabrasive grain layer having a thickness of several mm to several tens of mm is provided on the outer peripheral surface of the core portion or the dummy layer fixed to the outer circumference thereof. Since such a superabrasive grinding wheel provides a long tool life but is expensive, it is desired to use a relatively thin abrasive layer without waste as described above. When the layer disappears, there is a possibility that the work material slides on the dummy layer below the abrasive grain layer to generate a defective product. In particular, a mechanized or labor-saving production facility may generate a large number of defective products.
[0003]
On the other hand, when the thickness of the abrasive grain layer decreases and reaches its use limit, a use limit display mark provided in advance so as to be visually identifiable in the grindstone is exposed on the grinding surface. Has been proposed. Examples thereof include superabrasive grinding wheels described in Japanese Utility Model Publication No. 52-75892 and registered utility model No. 3049921.
[0004]
[Problems to be solved by the invention]
However, the superabrasive grinding wheel with the use limit display mark exposed on the grinding surface as described above can identify the use limit display mark appearing on the outer peripheral grinding surface in a state of rotating at a relatively high speed. Because it is difficult to observe the outer peripheral grinding surface with the rotation repeatedly stopped when approaching the use limit, the rotational deceleration time, stop time, and rotation rise time of the superabrasive grinding wheel are required. Therefore, there is a disadvantage that the dressing work efficiency is reduced, or the grinding time of the work material, that is, the loss of the actual operation time occurs, and it becomes difficult to automate the grinding work. Further, for example, in an NC controller, in order to prevent processing defects, a wheel replacement time is set and inputted in advance with a grindstone diameter larger than the actual grindstone discard diameter, and the superabrasive layer remains usable. There was also a drawback that the wheel was replaced early.
[0005]
The present invention has been made against the background of the above circumstances, and its purpose is to determine whether or not the use limit indication mark appears on the outer peripheral grinding surface during rotation of the superabrasive grinding wheel. It is an object to provide a superabrasive grinding wheel and a use limit determination device thereof.
[0008]
[The first to solve the problem 1 Means]
The invention according to claim 1 The gist of the use limit determination device is a portion provided with a superabrasive layer on the outer peripheral surface and located on the inner peripheral side by a preset use limit thickness from the outer peripheral surface of the superabrasive layer and in the circumferential direction. Is formed of a material that generates an AE signal different from that of the superabrasive layer during grinding or dressing, and the superabrasive layer is formed on the outer peripheral surface when the use limit thickness disappears from the outer peripheral side. In the superabrasive grinding wheel including the exposed use limit display part, a use limit judging device for judging whether or not the use limit display part appears on the outer peripheral grinding surface in the rotation state of the superabrasive grinding wheel. And (a) an AE signal detection device for detecting an AE signal generated during grinding or dressing of the superabrasive grinding wheel, and (b) based on a change in the AE signal detected by the AE signal detection device. Said And determining use limits determining unit that limits the display unit is exposed to the outer peripheral surface of the superabrasive grinding wheel is to contain.
[0009]
[No. 1 The invention's effect】
In this way, when a use limit display unit made of a material that generates an AE signal different from that of the superabrasive layer appears locally on the outer peripheral grinding surface, the superabrasive grinding wheel is ground or dressed. Since the generated AE signal includes a signal corresponding to the sliding contact with the use limit display unit, the use limit display unit determines that the use limit display unit is superabrasive based on the change of the AE signal. It is determined that the outer peripheral surface of the grinding wheel is exposed. For this reason, since it is automatically determined whether or not the use limit display mark appears on the outer peripheral grinding surface during rotation of the super abrasive grinding wheel, the rotation of the super abrasive grinding wheel to visually recognize the outer peripheral grinding surface is determined. In the case of dressing work, the work efficiency is improved, and when the work material is ground, the loss of the work time, that is, the actual operation time is eliminated. Further, even when the superabrasive grinding wheel is mounted at a position where it cannot be visually observed, its use limit is automatically determined, so that it is easy to automate the grinding operation in a wet grinding machine, an automatic grinding machine, or the like. In addition, since the superabrasive grinding wheel can be used until the superabrasive layer hardly remains, it is not necessary to replace the usable grindstone early. Furthermore, since the use limit display part is a part located on the inner peripheral side by the preset use limit thickness from the outer peripheral surface of the superabrasive grain layer and is provided in a part in the circumferential direction, the use limit is determined. Even in such a case, since the superabrasive layer is in sliding contact with the work material, roughening of the processed surface is suitably prevented.
[0010]
[The first to solve the problem 2 Means]
Also, The invention according to claim 4 The gist of the use limit determination device is a portion provided with a superabrasive layer on the outer peripheral surface and located on the inner peripheral side by a preset use limit thickness from the outer peripheral surface of the superabrasive layer and in the circumferential direction. A part of the material is composed of a material having a hue different from that of the superabrasive layer during grinding or dressing, and the superabrasive layer is exposed to the outer peripheral surface when the use limit thickness disappears from the outer peripheral side. In a superabrasive grinding wheel including a use limit display part, a use limit determination device for determining whether or not the use limit display part has appeared on the outer peripheral grinding surface in a rotating state of the superabrasive grinding wheel, (a) a reflected light detection device for detecting reflected light from the outer peripheral surface of the superabrasive grinding wheel, and (b) the use limit display unit based on a change in reflected light detected by the reflected light detection device. Exposed on the outer peripheral surface of the superabrasive grinding wheel. And determining use limits determining means is to include.
[0011]
[No. 2 The invention's effect】
In this way, when a use limit display portion made of a material having a hue different from that of the superabrasive layer appears locally on the outer peripheral grinding surface, the reflected light from the outer peripheral surface of the superabrasive grinding wheel is reflected in the reflected light. Since the signal corresponding to the hue of the use limit display section is included, the use limit display means that the use limit display section is exposed on the outer peripheral surface of the superabrasive grinding wheel based on the change in the reflected light. Is determined. For this reason, since it is automatically determined whether or not the above-mentioned usage limit display portion appears on the outer peripheral grinding surface in the rotation state of the super abrasive grinding wheel, the rotation of the super abrasive grinding wheel is necessary to visually recognize the outer peripheral grinding surface. In the case of dressing work, the work efficiency is improved, and when the work material is ground, the loss of the work time, that is, the actual operation time is eliminated. Further, even when the superabrasive grinding wheel is mounted at a position where it cannot be visually observed, its use limit is automatically determined, so that it is easy to automate the grinding operation in a wet grinding machine, an automatic grinding machine, or the like. In addition, since the superabrasive grinding wheel can be used until the superabrasive layer hardly remains, it is not necessary to replace the usable grindstone early. Furthermore, since the use limit display part is a part located on the inner peripheral side by the preset use limit thickness from the outer peripheral surface of the superabrasive grain layer and is provided in a part in the circumferential direction, the use limit is determined. Even when the workpiece is cut, the superabrasive layer is exclusively in sliding contact with the work material, so that roughening of the ground surface is suitably prevented.
[0012]
Other aspects of the invention
Where 1 In the present invention, preferably, the use limit determining means includes an average signal level calculating means for calculating an average signal level of the AE signal detected by the AE signal detecting device, and an AE calculated by the average signal level calculating means. Average signal level determination means for determining that the average signal level of the signal is below a preset average signal level determination reference value, and the average signal level of the AE signal is preset by the average signal level determination means The use limit display unit is determined to be exposed on the outer peripheral surface of the superabrasive grinding wheel based on the determination that the average signal level is below the reference value. In this way, during rotation of the superabrasive grinding wheel, that is, during grinding, the average signal level determination means determines that the average signal level of the AE signal is below the preset average signal level determination reference value. Based on the above, it is automatically determined that the use limit display portion is exposed on the outer peripheral surface of the superabrasive grinding wheel.
[0013]
The first 1 In the present invention, preferably, the use limit determination means includes frequency analysis means for performing frequency analysis of the AE signal detected by the AE signal detection device, and frequency domain of the AE signal subjected to frequency analysis by the frequency analysis means. Among them, it is determined that the magnitude of the signal in the frequency region corresponding to the frequency at which the use limit display section passes through a predetermined location on the outer periphery of the superabrasive grinding wheel exceeds a preset frequency component determination reference value. Frequency domain signal determination means for performing the frequency domain signal determination means to correspond to a frequency at which the use limit display portion passes through a predetermined location on the outer periphery of the superabrasive grinding wheel in the frequency domain of the AE signal. Based on the determination that the magnitude of the signal in the frequency domain exceeds a preset frequency component determination reference value, the use limit display unit displays the superabrasive It is to determine that which is exposed to the outer peripheral surface of the grinding wheel. By doing so, during the rotation of the superabrasive grinding wheel, that is, during grinding, the frequency limit of the AE signal is set so that the use limit display portion passes through a predetermined location on the outer periphery of the superabrasive grinding wheel. The use limit display unit is exposed on the outer peripheral surface of the superabrasive grinding wheel based on the determination that the magnitude of the corresponding frequency domain signal exceeds a preset frequency component determination reference value. Is automatically determined.
[0014]
The first 1 In the invention, preferably, the use limit display part is a part of the outer peripheral surface of the general abrasive layer provided inside the superabrasive grain layer slightly protruding to the outer peripheral side. The grain layer is composed of a grindstone structure including main abrasive grains having a predetermined grain size and sub-abrasive grains having an average grain size of 1/2 to 1/3 of the main abrasive grains. In this way, even if the use limit display portion comes into contact with the work material, a defective product is not generated, and the spring back at the time of press forming the general abrasive layer can be reduced and is high in the radial direction, that is, in the thickness direction. There is an advantage that a dimensional accuracy can be obtained and, for example, a general abrasive layer having a thickness tolerance of about 0.02 mm can be obtained with respect to a conventional thickness tolerance of about 0.2 mm.
[0015]
The first 2 In the present invention, preferably, the use limit determination means is calculated by an average signal level calculation means for calculating an average signal level of a signal representing reflected light detected by the reflected light detection device, and the average signal level calculation means. Average signal level determination means for determining whether the average signal level of the signal representing the reflected light exceeds or falls below a preset average signal level determination reference value, and is reflected by the average signal level determination means Based on the determination that the average signal level of the signal representing light exceeds or falls below a preset average signal level determination reference value, the use limit display unit is exposed on the outer peripheral surface of the superabrasive grinding wheel. It is determined to have done. In this way, during rotation of the superabrasive grinding wheel, that is, during grinding, the average signal level of the signal representing the reflected light by the average signal level determination means exceeds the preset average signal level determination reference value or It is automatically determined that the use limit display unit is exposed on the outer peripheral surface of the superabrasive grinding wheel based on the determination that the value is lower.
[0016]
The first 2 In the invention, it is preferable that the use limit determination unit includes a frequency analysis unit that performs frequency analysis of a signal that represents the reflected light detected by the reflected light detection device, and a reflected light that is frequency-analyzed by the frequency analysis unit. The frequency component judgment reference value in which the magnitude of the signal in the frequency region corresponding to the frequency at which the use limit display unit passes through a predetermined location on the outer periphery of the superabrasive grinding wheel among the frequency region of the signal to be represented is set. Frequency domain signal determination means for determining that the upper limit is exceeded, and the frequency domain signal determination means allows the use limit display portion of the frequency domain of the signal representing the reflected light to be the outer circumference of the superabrasive grinding wheel. Based on the determination that the magnitude of the signal in the frequency domain corresponding to the frequency passing through the predetermined location exceeds the preset frequency component determination reference value, It is to determine the limit display unit is exposed to the outer peripheral surface of the superabrasive grinding wheel. In this way, during the rotation of the superabrasive grinding wheel, that is, during the grinding process, the use limit display portion of the frequency domain of the signal representing the reflected light is displayed on the superabrasive grinding wheel by the frequency domain signal determining means. When the use limit display unit determines that the magnitude of the signal in the frequency region corresponding to the frequency passing through a predetermined location on the outer circumference of the outer circumference exceeds a preset frequency component determination reference value, It is automatically determined that the outer peripheral surface of the grain grinding wheel is exposed.
[0017]
The first 1 Invention and No. 2 In the invention, preferably, the superabrasive grinding wheel is provided with a position mark indicating a position on the side opposite to the position where the use limit display portion is located or the rotation center. In this way, when attaching the superabrasive grinding wheel to the rotary support shaft on which it is supported, the fitting tolerance between the superabrasive grinding wheel and the rotary support shaft is obtained by using the position mark. For example, since the use limit display portion can be fixed so as to be positioned on the outer peripheral side by 20 μm, there is an advantage that the use limit display portion is reliably exposed on the outer peripheral surface of the superabrasive grinding wheel.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a use limit determination device 10 according to an application example of the present invention will be described in detail with reference to the drawings.
[0019]
In FIG. 1, the superabrasive grinding wheel 12 is fixed to a rotation support shaft 14 so as to be driven to rotate around a horizontal axis, for example. As shown in detail in FIGS. 2 and 3, the superabrasive grinding wheel 12 includes a mounting base 16 and a disk-shaped base 18 made of, for example, steel, and an outer peripheral surface of the base 18. A general abrasive grain layer, that is, a dummy layer 20 fixed to the outer peripheral surface of the dummy layer 20 and a superabrasive grain layer 22 fixed to the outer peripheral surface of the dummy layer 20. The superabrasive layer 22 is, for example, a vitrified grindstone having a degree of concentration of about 50 and a degree of bond of about 4 to 5 mm in which CBN abrasive grains having a grain size of No. 140 to No. 170 are joined by vitrified bonds. It consists of an organization. The dummy layer 20 is derived from a material different from that of the superabrasive grain layer 22 and has a different hue, and general abrasive grains having two kinds of average grain sizes such as fused alumina, silicon carbide, and molten mullite are provided. It is composed of a vitrified grinding wheel structure having a thickness of about 4.0 mm bonded by vitrified bonds. The dummy layer 20 is composed of, for example, about 60th molten mullite (main abrasive grains), about 1/2 to 1/3 of the grain size, for example, about 180th molten mullite (sub-abrasive grains), and vitrified bond. These ratios are about 41.8% by volume, 17.9% by volume, and 19.1% by volume.
[0020]
As shown in FIG. 3, the superabrasive grinding wheel 12 is provided with a use limit display 24 that protrudes from the part of the outer peripheral surface of the dummy layer 20 to the outer peripheral side by a very small distance A of about 0.04 mm, for example. It has been. The use limit state in which the outer peripheral surface of the superabrasive grinding wheel 12, that is, the superabrasive layer 22 is consumed and reduced in thickness due to grinding or dressing of the work material, so that the superabrasive layer 22 is hardly left. Then, the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12. Further, the superabrasive grinding wheel 12 is provided with a position mark 25 indicating a position on the opposite side to the position where the use limit display portion 24 is located with respect to the rotation center.
[0021]
FIG. 1 shows a state of a dressing operation which is completed by repeating a notch of about 0.002 mm several times using, for example, a diamond dresser 26 in order to correct or sharpen the entire outer peripheral surface of the superabrasive grinding wheel 12. Has been. The diamond dresser 26 is fixed to a holder 28 that is fed in a direction parallel to the rotational axis of the superabrasive grinding wheel 12, and the tip is in contact with the outer peripheral surface of the superabrasive grinding wheel 12 and slightly cut. Thus, it can be moved across the width direction of the outer peripheral surface.
[0022]
The diamond dresser 26 detects ultrasonic waves, that is, AE (Acoustic Emission) emitted when abrasive grains exposed on the outer peripheral surface of the superabrasive grinding wheel 12 are crushed by contact with the tip of the diamond dresser 26. An AE sensor 30 for outputting an AE signal representing the ultrasonic wave is provided. The ultrasonic waves generated by the crushing of the abrasive grains exposed on the outer peripheral surface of the superabrasive grinding wheel 12 propagate to the diamond dresser 26 via the grinding liquid flowing down to the dressing point, and are continuously detected by the AE sensor 30. It has come to be.
[0023]
The AE signal detected by the AE sensor 30 passes through a filter 32 that exclusively passes the frequency component of the AE signal and amplifies the signal, and an A / D converter 34 that converts an analog signal into a digital signal, and sequentially performs an electronic operation. Continuously supplied to the controller 36. The electronic arithmetic control device 36 is a so-called microcomputer including a CPU, a ROM, a RAM, and an interface. The CPU processes an input signal according to a program stored in advance in the ROM while using a temporary storage function of the RAM. The display device 38 and the superabrasive grinding wheel 12 for rotating the superabrasive grinding wheel 12 to indicate the usage limit signal SL indicating the usage limit of the abrasive grinding wheel 12 with light, image or sound, etc. To the automatic stop device 40 for automatically stopping the motor (not shown).
[0024]
In the one-dot chain line in FIG. 1, functional blocks for explaining the main part of the control function of the electronic arithmetic control device 36 are shown. The electronic arithmetic control device 36 functions as a use limit determination means, and the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12 based on the change of the AE signal detected by the AE sensor 30. Determine what happened. The electronic arithmetic control device 36 includes an average signal level calculation means 46, an average signal level determination means 48, a frequency analysis means 50, a frequency domain signal determination means 52, and a use limit output means 54 configured by the program.
[0025]
The average signal level calculation means 46 is a moving average value within the predetermined movement section of the use limit signal SL continuously input to the electronic arithmetic control device 36, that is, the average signal level S. _AV Is calculated. This moving average calculation section is set to at least a period during which the use limit display unit 24 passes, for example, a period of one rotation period or more of the superabrasive grinding wheel 12. The average signal level determination means 48 is an average signal level S of the AE signal calculated by the average signal level calculation means 46. _AV Is the preset average signal level judgment reference value S _AV1 It is determined whether or not the value has fallen below. This average signal level judgment reference value S _AV1 Is the average signal level S when the use limit display unit 24 composed of general abrasives having a hardness lower than that of the superabrasive grains is exposed on the outer peripheral surface of the superabrasive grinding wheel 12. _AV In order to determine the decrease in the value, the value is set higher than the decrease value by a predetermined value. For example, the average signal level S when the use limit display unit 24 is not exposed. _AV Is “10” and the average signal level S when the use limit display 24 is exposed is shown. _AV Is “9.3”, it is set to a value between “10” and “9.3”.
[0026]
The frequency analysis means 50 performs frequency analysis of the continuously input AE signal using, for example, fast Fourier transform, and calculates the signal intensity for each frequency component constituting the AE signal, for example, as shown in FIG. . Of the frequency components of the AE signal frequency-analyzed by the frequency analysis unit 50, the frequency domain signal determination unit 52 uses a predetermined position where the use limit display unit 24 is fixed at the outer periphery of the superabrasive grinding wheel 12. The magnitude S of the signal in the frequency domain B corresponding to the passing frequency _FT Is a preset frequency component judgment reference value S _FT1 It is determined whether or not In the frequency component of the AE signal shown in FIG. 4, when the use limit display unit 24 is exposed on the outer periphery of the superabrasive grinding wheel 12, the frequency region B includes a frequency component corresponding to the passage period of the use limit display unit 24. Signal component becomes larger and peaks occur, so that the frequency component determination reference value S _FT1 Is experimentally set in advance to determine the presence or absence of the peak.
[0027]
The use limit output means 54 is an average signal level S of the AE signal calculated by the average signal level calculation means 46 by the average signal level determination means 48. _AV Is the preset average signal level judgment reference value S _AV1 Of the AE signal frequency-analyzed by the frequency analysis unit 50 by the frequency domain signal determination unit 52, the use limit display unit 24 has an outer periphery of the superabrasive grinding wheel 12 The magnitude S of the signal in the frequency domain B corresponding to the frequency passing through the predetermined fixed position determined in FIG. _FT Is a preset frequency component judgment reference value S _FT1 , The use limit signal SL indicating the use limit of the superabrasive grinding wheel 12 is supplied to the display device 38, and a display indicating the use limit of the superabrasive grinding wheel 12 is displayed. While executing using an image or an audio | voice etc., it supplies to the rotation stop apparatus 40 and the motor which is not shown in figure which is rotationally driving the superabrasive grinding wheel 12 is stopped automatically.
[0028]
As described above, according to the present embodiment, the use limit display unit 24 composed of abrasive grains different in hardness from the superabrasive layer 22 appears locally on the outer peripheral grinding surface of the superabrasive grinding wheel 12. Since the AE signal generated during dressing of the superabrasive grinding wheel 12 includes a signal corresponding to the sliding contact with the use limit display unit 24, the use limit determining means (electronic calculation control device 36). ), It is determined that the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12 based on the change in the AE signal. For this reason, since it is automatically determined whether or not the use limit display unit 24 appears on the outer peripheral grinding surface while the super abrasive grinding wheel 12 is rotating, the super abrasive grinding wheel is used to visually recognize the outer peripheral grinding surface. There is no need to stop the rotation of 12, the dressing work efficiency is improved, and the loss of actual operation time is eliminated when the work material is ground. Further, even if the superabrasive grinding wheel 12 is mounted at a position where it cannot be seen, its use limit is automatically determined, so that it is easy to automate the grinding work in wet grinding, an automatic grinding machine or the like. Moreover, since the superabrasive grinding wheel can be used until the superabrasive grain layer 22 hardly remains, it is not necessary to replace the usable grindstone early.
[0029]
In addition, according to the present embodiment, the electronic arithmetic control device 36 functioning as a use limit determination unit is configured to use the average signal level S of the AE signal detected by the AE sensor 30. _AV The average signal level calculating means 46 for calculating the average signal level S of the AE signal calculated by the average signal level calculating means 46 _AV Is the preset average signal level judgment reference value S _AV1 Average signal level determination means 48 for determining that the average signal level of the AE signal is reduced by the average signal level determination means 48. _AV Is the preset average signal level judgment reference value S _AV1 It is determined that the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12 based on the determination that the value is lower than. Thereby, during rotation of the superabrasive grinding wheel, for example, during dressing or grinding, it is automatically determined that the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12.
[0030]
In addition, according to the present embodiment, the electronic arithmetic control device 36 functioning as a use limit determination unit includes a frequency analysis unit 50 that performs frequency analysis of the AE signal detected by the AE sensor 30, and a frequency analysis unit 50 that performs frequency analysis. Of the analyzed frequency domain of the AE signal, the signal size S in the frequency domain B corresponding to the frequency at which the use limit display unit 24 passes through a predetermined location on the outer periphery of the superabrasive grinding wheel 12. _FT Is a preset frequency component judgment reference value S _FT1 Frequency domain signal determination means 52 for determining that the frequency range signal exceeds the frequency range B of the frequency domain B of the AE signal. _FT Is a preset frequency component judgment reference value S _FT1 Since the use limit display unit 24 is determined to be exposed on the outer peripheral surface of the superabrasive grinding wheel 12 based on the determination that the superabrasive grinding wheel is rotating. During or during grinding, it is automatically determined that the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12.
[0031]
Further, in the electronic arithmetic control device 36 of this embodiment, the average signal level S of the AE signal is received by the average signal level determination means 48. _AV Is the preset average signal level judgment reference value S _AV1 Or the magnitude S of the signal in the frequency domain B is determined by the frequency domain signal determination means 52. _FT Is a preset frequency component judgment reference value S _FT1 If it is determined that the use limit signal SL exceeds the use limit output means 54 for supplying the use limit signal SL indicating the use limit of the superabrasive grinding wheel 12 to the display device 38 and the rotation stop device 40. There is an advantage that the reliability of determination of the use limit of the superabrasive grinding wheel 12 can be further improved.
[0032]
Further, according to the present embodiment, the use limit display unit 24 is a part of the outer peripheral surface of the dummy layer 20 provided inside the superabrasive grain layer 22 slightly protruding to the outer peripheral side. The dummy layer 20 is composed of a grindstone structure including main abrasive grains having a predetermined particle diameter and sub-abrasive grains having an average particle diameter of 1/2 to 1/3 of the main abrasive grains. Even if the use limit display unit 24 comes into contact with the work material, a defective product is not generated, and the spring back at the time of press forming the dummy layer 20 can be reduced, and high dimensional accuracy in the radial direction, that is, the thickness direction can be obtained. For example, there is an advantage that a dummy layer 20 having a thickness tolerance of about 0.02 mm can be obtained with respect to a conventional thickness tolerance of about 0.2 mm.
[0033]
Further, the superabrasive grinding wheel 12 of the above-described embodiment is provided with a position mark 25 indicating a position on the opposite side to the position where the use limit display section 24 is located with respect to the rotation center. For this reason, when the superabrasive grinding wheel 12 is attached to the rotation support shaft 14 on which the superabrasive grinding wheel 12 is supported, the superabrasive grinding wheel 12 is rotated with the position mark 25 positioned upward using the position mark 25. Since the fitting limit between the superabrasive grinding wheel 12 and the rotating support shaft 14 is fixed to the outer peripheral side by fastening to the support shaft 14, for example, 20 μm, There exists an advantage by which the use limit display part 24 is reliably exposed to the outer peripheral surface of the superabrasive grinding wheel 12.
[0034]
Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.
[0035]
The electronic calculation control device 36 functioning as a use limit determining means in the use limit determining device 60 of FIG. 5 is such that the superabrasive grinding wheel 12 is grinding the work material 62 and the outer peripheral surface of the superabrasive grinding wheel 12. And a reflected light detecting device 66 for continuously receiving reflected light from a portion irradiated by the light source 64 in the outer peripheral surface of the superabrasive grinding wheel 12, and the reflected light detecting device. A filter 68 for removing noise from the light reception signal output from 66 is provided. The electronic arithmetic control unit 36 includes an average signal level calculation means 70, an average signal level determination means 72, a frequency analysis means 74, a frequency domain signal determination means 76, and a use limit output means 78 having the same control functions as those of the above-described embodiments. It has.
[0036]
In the average signal level calculation means 70 in the use limit determination device 60, an average signal level H which is a moving average value of the received light signal continuously input. _AV Is calculated. In the average signal level determination means 72, the average signal level H _AV Is a preset average signal level judgment reference value H _AV1 It is determined whether or not the value has fallen below. This average signal level judgment reference value H _AV1 Is the average signal level H when the use limit display unit 24 having a hue different from that of the superabrasive layer 22 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12. _AV It is a value set to determine the change of. When the shade indicating the hue of the use limit display unit 24 is lighter than the superabrasive layer 22, the average signal level H when the use limit display unit 24 is not exposed. _AV When the shade indicating the hue of the use limit display unit 24 is darker than the superabrasive grain layer 22, the average signal level H when the use limit display unit 24 is not exposed is set. _AV Is set to a higher value.
[0037]
The frequency analysis means 74 performs frequency analysis of the received light signal that is continuously input using, for example, fast Fourier transform, and calculates the signal intensity for each frequency component that constitutes the received light signal, for example, as shown in FIG. . Of the frequency components of the light reception signal frequency-analyzed by the frequency analysis unit 74, the frequency domain signal determination unit 76 uses a predetermined position where the use limit display unit 24 is fixed on the outer periphery of the superabrasive grinding wheel 12. The magnitude (signal intensity) H of the signal in the frequency domain B corresponding to the passing frequency _FT Is a preset frequency component judgment reference value H _FT1 It is determined whether or not In the frequency component of the received light signal shown in FIG. 4, when the use limit display unit 24 is exposed on the outer periphery of the superabrasive grinding wheel 12, the frequency region B includes a frequency component corresponding to the passage period of the use limit display unit 24. Signal component becomes larger and peaks occur, so that the frequency component determination reference value H _FT1 Is experimentally set in advance to determine the presence or absence of the peak.
[0038]
The use limit output means 78 receives the average signal level H of the received light signal by the average signal level determination means 72. _AV Is a preset average signal level judgment reference value H _AV1 It is determined whether or not the frequency limit signal is determined by the frequency domain signal determination means 76, and the use limit display unit 24 is fixed to a position determined on the outer periphery of the superabrasive grinding wheel 12 by the frequency domain signal determination means 76. The magnitude H of the signal in the frequency domain B corresponding to the frequency passing through the predetermined location _FT Is a preset frequency component judgment reference value H _FT1 , The use limit signal SL indicating the use limit of the superabrasive grinding wheel 12 is supplied to the display device 38, and a display indicating the use limit of the superabrasive grinding wheel 12 is displayed. While executing using an image or an audio | voice etc., it supplies to the rotation stop apparatus 40 and the motor which is not shown in figure which is rotationally driving the superabrasive grinding wheel 12 is stopped automatically.
[0039]
According to the present embodiment, when the use limit display unit 24 made of a material having a hue different from that of the superabrasive grain layer 22 appears locally on the outer peripheral grinding surface of the superabrasive grinding stone 12, the outer limit surface Since the reflected light includes a signal corresponding to the hue of the use limit display unit 24, the use limit display unit based on the change in the reflected light by the use limit determining means (electronic calculation control device 36). It is determined that 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12. For this reason, since it is automatically determined whether or not the use limit display unit 24 appears on the outer peripheral grinding surface while the super abrasive grinding wheel 12 is rotating, the super abrasive grinding wheel is used to visually recognize the outer peripheral grinding surface. It is not necessary to stop the rotation of 12 and the efficiency is improved in the case of dressing work, and the loss of the grinding time, that is, the actual operation time is eliminated when the work material 62 is ground. Further, even if the superabrasive grinding wheel 12 is mounted at a position where it cannot be seen, its use limit is automatically determined, so that it is easy to automate the grinding work in wet grinding, an automatic grinding machine or the like. Moreover, since the superabrasive grinding wheel can be used until the superabrasive grain layer 22 hardly remains, it is not necessary to replace the usable grindstone early. Furthermore, since the use limit display unit 24 is a portion located on the inner peripheral side by a preset use limit thickness from the outer peripheral surface of the superabrasive grain layer 22 and is provided in a part in the circumferential direction, the use limit is limited. Even when judged, since the superabrasive grain layer 22 is exclusively in sliding contact with the work material 62, roughening of the ground surface is suitably prevented.
[0040]
In the present embodiment, the electronic calculation control device 36 functioning as a use limit determination means is configured to receive the average signal level H of the received light signal representing the reflected light detected by the reflected light detection device 66. _AV The average signal level calculation means 70 for calculating the average signal level H of the received light signal calculated by the average signal level calculation means 70 _AV Is a preset average signal level judgment reference value H _AV1 Average signal level determination means 72 for determining whether the signal is above or below the average signal level H of the signal representing the reflected light by the average signal level determination means 72 _AV Is a preset average signal level judgment reference value H _AV1 It is determined that the use limit display unit 24 has been exposed on the outer peripheral surface of the superabrasive grinding wheel 12 based on the determination that it has exceeded or fallen below. For this reason, it is automatically determined that the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12.
[0041]
In the present embodiment, the electronic calculation control device 36 functioning as a use limit determination means includes a frequency analysis means 74 that performs frequency analysis of a received light signal that represents reflected light detected by the reflected light detection device 66, and a frequency analysis thereof. The magnitude H of the signal in the frequency domain B corresponding to the frequency at which the use limit display unit 24 passes through a predetermined location on the outer periphery of the superabrasive grinding wheel 12 in the frequency domain of the received light signal frequency-analyzed by the means 74. _FT Is a preset frequency component judgment reference value H _FT1 Frequency domain signal determination means 76 for determining that the frequency range B is exceeded. By the frequency domain signal determination means 76, the magnitude H of the signal in the frequency domain B is determined. _FT Is a preset frequency component judgment reference value H _FT1 The use limit display unit 24 determines that the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12 based on the determination that the use limit display unit 24 exceeds the superabrasive grinding. It is automatically determined that the outer surface of the grindstone 12 is exposed.
[0042]
Further, in the electronic arithmetic control device 36 of this embodiment, an average signal level H of the received light signal is received by the average signal level determination means 70. _AV Is a preset average signal level judgment reference value H _AV1 Or the magnitude of the signal H in the frequency domain B is determined by the frequency domain signal determination means 76. _FT Is a preset frequency component judgment reference value H _FT1 If it is determined that the use limit signal SL is exceeded, a use limit output means 78 is provided for supplying a use limit signal SL indicating the use limit of the superabrasive grinding wheel 12 to the display device 38 and the rotation stop device 40. There is an advantage that the reliability of determination of the use limit of the superabrasive grinding wheel 12 can be further improved.
[0043]
6 and 7 show another configuration example of the superabrasive grinding wheel 12. The superabrasive grinding wheel 12 of this embodiment is configured by attaching a plurality of segment tip grinding stones 80 to the outer peripheral surface of the base metal 18. The segment chip grindstone 80 is configured by the superabrasive grain layer 22 being fixed to the outside of the dummy layer 20. The dummy layer 20 of a predetermined number of segment chip whetstones 80 in the present embodiment, that is, one segment chip whetstone 80 a in this embodiment, functions as the use limit display unit 24, and thus is compared with other segment chip whetstones 80. For example, it is enlarged by about 0.04 mm. The superabrasive grinding wheel 12 of the present embodiment is also provided with a position mark 25 for indicating a position opposite to the center line of the circumferential position of the use limit display portion 24.
[0044]
As mentioned above, although one Example of this invention was described using drawing, this invention is applied also in another aspect.
[0045]
For example, in FIG. 1 described above, the superabrasive grinding wheel 12 during the dressing operation is shown. However, as shown in FIG. 5, it may be during the grinding operation for grinding the work material 62. In this case, the AE sensor 30 is provided on the work material 62. The AE sensor 30 may be provided in the superabrasive grinding wheel 12.
[0046]
Moreover, the use limit display part 24 of the above-mentioned Example may be made to incline with respect to the line parallel to a rotating shaft center in the outer peripheral surface of the superabrasive grinding wheel 12. In this way, a sudden change in the grinding efficiency of the work material 62 in a state where the use limit display unit 24 is exposed on the outer peripheral surface of the superabrasive grinding wheel 12 is avoided. Furthermore, the grindstone limit display unit 24 does not necessarily have to be provided in the entire grindstone width dimension, and may be a part of the center or end of the grindstone width dimension.
[0047]
Further, the position mark 25 of the above-described embodiment indirectly indicates the use limit display unit 24 by indicating the position opposite to the center line of the circumferential position of the use limit display unit 24 in the superabrasive grinding wheel 12. However, the position of the use limit display unit 24 may be directly indicated by providing it near the use limit display unit 24.
[0048]
Moreover, although the case where only one of the above-described use limit display units 24 is provided in the superabrasive grinding wheel 12 is shown, a plurality of the use limit display units 24 are provided at positions at equal intervals or unequal intervals in the circumferential direction. Also good.
[0049]
The dummy layer 20 is composed of fused mullite abrasive grains or general abrasive grains such as molten alumina and silicon carbide in order to generate an AE signal different from that of the superabrasive grain layer 22. Inorganic material particles may be used. For example, the dummy layer 20 may be a material or a structure that can obtain a change in the AE signal indicating that the use limit display unit 24 is exposed, that is, a change in the average signal level of the AE signal, or a change in the signal intensity in a specific frequency region B. That's fine. For this reason, the dummy layer 20 may have, for example, a configuration in which the content of superabrasive grains in the superabrasive grain layer 22 is reduced, or the superabrasive grains and the above-described molten mullite or general abrasive grains are mixed. It may be a configuration.
[0050]
In the embodiment of FIG. 5 described above, the reflected light detection device 66 may be a color reflected light detection device that detects reflected light in color. In such a case, the determination accuracy can be further improved by using a color filter that exclusively passes the hue wavelength of the use limit display unit 24.
[0051]
In addition, although the above-described electronic arithmetic control devices 36 and 60 are constituted by so-called microcomputers, they are constituted by electronic components constituting individual logic elements in order to generate the same control function without using a program. You may comprise by what is called a hard logic and a comparator.
[0052]
The above description is only an example of the present invention, and the present invention can be variously modified without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a use limit judging device for a superabrasive grinding wheel according to an embodiment of the present invention.
FIG. 2 is a front view illustrating a superabrasive grinding wheel used in the apparatus of FIG.
3 is a view for explaining a main part of a superabrasive grinding wheel used in the apparatus of FIG. 1, and is an enlarged view of a main part of FIG.
4 is a diagram illustrating an example of a spectrum of an AE signal subjected to frequency analysis by the frequency analysis unit in FIG. 1. FIG.
FIG. 5 is a block diagram illustrating a configuration of a use limit judging device for a superabrasive grinding wheel in another embodiment of the present invention.
6 is a front view for explaining a superabrasive grinding wheel according to another embodiment of the present invention, which corresponds to FIG. 2. FIG.
7 is an enlarged view illustrating a main part of the superabrasive grinding wheel in FIG. 6 and corresponds to FIG. 3;
[Explanation of symbols]
10, 60: Use limit judgment device
12: Super abrasive grinding wheel
22: Super abrasive layer
24: Use limit display section
30: AE sensor (AE signal detection device)
36: Electronic calculation control device (use limit judging means)
46, 70: Mean signal level calculation means
48, 72: Mean signal level determination means
50, 74: Frequency analysis means
52, 76: Frequency domain signal determination means

Claims (8)

A superabrasive layer is provided on the outer peripheral surface, and is a portion located on the inner peripheral side by a preset use limit thickness from the outer peripheral surface of the superabrasive layer, and in a part of the circumferential direction during grinding or dressing A superabrasive comprising a material for generating an AE signal different from that of the superabrasive grain layer, and including a use limit display portion that is exposed to the outer peripheral surface when the superabrasive grain layer disappears from the outer peripheral side by the useable limit thickness. In the grain grinding wheel, a use limit judgment device for judging whether or not the use limit display part has appeared on the outer peripheral grinding surface in a rotating state of the superabrasive grinding wheel,
An AE signal detection device for detecting an AE signal generated during grinding or dressing of the superabrasive grinding wheel;
Use limit determination means for determining that the use limit display unit is exposed on the outer peripheral surface of the superabrasive grinding wheel based on a change in the AE signal detected by the AE signal detection device. Use limit judgment device of super abrasive grinding wheel. The use limit judging means is
Average signal level calculation means for calculating an average signal level that is a moving average value in a section in which at least the use limit display part of the AE signal detected by the AE signal detection device passes through a detection point of the AE signal detection device;
Average signal level determination means for determining that the average signal level of the AE signal calculated by the average signal level calculation means is below a preset average signal level determination reference value, and the average signal level determination means Based on the determination that the average signal level of the AE signal is below a preset average signal level determination reference value, it is determined that the use limit display unit is exposed on the outer peripheral surface of the superabrasive grinding wheel. The apparatus for determining the use limit of the superabrasive grinding wheel according to claim 1 . The use limit judging means is
Frequency analysis means for performing frequency analysis of the AE signal detected by the AE signal detection device;
Of the frequency region of the AE signal frequency-analyzed by the frequency analysis means, a signal in a frequency region corresponding to a passing period in which the use limit display unit passes through a predetermined location on the outer periphery of the superabrasive grinding wheel is preset. Frequency domain signal determination means for determining that the frequency component determination reference value has been exceeded, and the frequency domain signal determination means causes the use limit display portion of the frequency domain of the AE signal to perform the superabrasive grinding. Based on the determination that the signal in the frequency region corresponding to the passage period passing through a predetermined location on the outer periphery of the grindstone exceeds a preset frequency component judgment reference value, the use limit display unit displays the superabrasive grain. use limit determination device superabrasive grinding wheel of claim 1 in which determining that exposed to the outer peripheral surface of the grinding wheel. The superabrasive grinding wheel according to any one of claims 1 to 3, wherein the material that generates an AE signal different from that of the superabrasive layer constituting the use limit display unit of the superabrasive grinding wheel includes general abrasives. Use limit judgment device. A superabrasive layer is provided on the outer peripheral surface, and is a portion located on the inner peripheral side by a preset use limit thickness from the outer peripheral surface of the superabrasive layer, and in a part of the circumferential direction during grinding or dressing A superabrasive grinding wheel composed of a material having a hue different from that of the superabrasive grain layer and including a use limit display portion exposed to the outer peripheral surface when the superabrasive grain layer disappears from the outer peripheral side by the use limit thickness. In the use limit determination device for determining whether or not the use limit display portion appeared on the outer peripheral grinding surface in the rotation state of the superabrasive grinding wheel,
A reflected light detection device for detecting reflected light from the outer peripheral surface of the superabrasive grinding wheel;
Use limit determination means for determining that the use limit display unit is exposed on the outer peripheral surface of the superabrasive grinding wheel based on a change in the reflected light detected by the reflected light detection device. Use limit judgment device of super abrasive grinding wheel. The use limit judging means is
Average signal level calculation for calculating an average signal level which is a moving average value in a section where at least the use limit display portion of the signal representing the reflected light detected by the reflected light detection device passes the detection point of the reflected light detection device Means,
Average signal level determination means for determining whether the average signal level of the signal representing the reflected light calculated by the average signal level calculation means exceeds or falls below a preset average signal level determination reference value, and When the average signal level determining means determines that the average signal level of the signal representing the reflected light exceeds or falls below a preset average signal level determination reference value, the use limit display unit displays the superabrasive. 6. The apparatus for determining the use limit of a superabrasive grinding wheel according to claim 5, wherein it is determined that the outer periphery of the grain grinding wheel is exposed. The use limit judging means is
Frequency analysis means for performing frequency analysis of a signal representing reflected light detected by the reflected light detection device;
Of the frequency region of the signal representing the reflected light frequency-analyzed by the frequency analysis means, the signal in the frequency region corresponding to the passage period in which the use limit display unit passes through a predetermined location on the outer periphery of the superabrasive grinding wheel. Frequency domain signal determination means for determining that the magnitude exceeds a preset frequency component determination reference value, and the use of the frequency domain of the signal representing the reflected light by the frequency domain signal determination means Based on the fact that the limit display unit has determined that the magnitude of the signal in the frequency region corresponding to the passage period passing through a predetermined location on the outer periphery of the superabrasive grinding wheel has exceeded a preset frequency component determination reference value. The use limit determination device for a superabrasive grinding wheel according to claim 5, wherein the use limit display unit determines that the outer peripheral surface of the superabrasive grinding wheel is exposed. The use limit of the superabrasive grinding wheel according to any one of claims 5 to 7, wherein the material having a hue different from that of the superabrasive layer constituting the use limit display part of the superabrasive grinding wheel includes general abrasive grains. Judgment device.

Images