COMMUNICATION DEVICE

Abstract

A communication device (100) includes a sensor (S) attached to a detection object (52, T) and outputting an analog detection signal (SA1), and a modulated laser generating device (103) generating a modulated laser (SL) by subjecting a laser fundamental wave to modulation processing based on the analog detection signal.

Description

TECHNICAL FIELD

[0001] The present invention relates to a communication device. BACKGROUND OF THE INVENTION

[0002] Patent Document 1 describes an AE sensor mounted on a member for holding a grinding wheel, wherein the AE sensor detects elastic waves generated when a workpiece is ground by the grinding wheel and outputs AE signals, and transmits the AE signal as radio waves through wireless communication to determine whether the grinding wheel is glazed or chipped or damaged.

[0003] Patent Document 2 describes a communication system that transmits and receives information data using laser light as digital signals. In this communication system, bright light is used as "on" and dark light as "off," and information data is imparted to the laser light by converting the laser light into digital signals by expressing the length of the "on" time and the length of the "off" time. Turning a laser light source on and off, thereby generating bright light when it is on and dark light when it is off, is described therein as a method for generating bright light and dark light.Another method for generating bright light and dark light is described in which a light source of laser light is continuously switched on and an optical modulator is used to vary the intensity of the laser light to generate bright light and dark light. PATENT LITERATURE Patent Document 1: WO 2021 / 153042 Patent Document 2: JP 2022-36928 A SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0004] In recent years, there has been a demand to detect the surface texture, etc., of a workpiece based on information obtained during machining, for example. It has recently been discovered that when detecting the surface texture, etc., of a workpiece using the AE sensor mounted on the grinding wheel holding member, etc., as described in Patent Document 1, the components included in the analog signals output from the AE sensor that strongly correlate with the surface texture of the workpiece include signals in a high-frequency band of, for example, 1.0 MHz or higher.

[0005] However, the strength of analog signals in the high-frequency band of 1.0 MHz or higher is extremely weak. In wireless communication using radio waves, the weak analog signals in the high-frequency band transmitted wirelessly are affected by various types of noise, such as EMC noise generated by machine tools and other equipment in operation, switching noise generated by power supplies, and so on. Therefore, it is difficult to extract the desired analog signals on a receiving device that receives the AE signals transmitted by radio waves, and appropriate data analysis cannot be performed.

[0006] Patent Document 2 describes the use of visible laser light instead of radio waves. Patent Document 2 describes a technology for transmitting laser light as digital I / O signals. When transmitting analog signals such as AE signals using a laser, as described in Patent Document 2, the analog signals such as AE signals or the like must undergo A / D conversion to generate digital I / O signals. The converted digital I / O signals are then used to generate laser light that alternates between bright and dark light. At the receiving device, analysis of the laser light of the digital I / O signals is required.

[0007] Laser beam oscillators that enable the receiving device to analyze high-frequency band analog signals using laser light are expensive. Therefore, even using the device described in Patent Document 2, it is not easy to perform communication of analog signals in a high-frequency band using laser light.

[0008] The present invention has been made in view of such problems and aims to provide a communication device that is less susceptible to noise and can communicate inexpensively even when the analog detection signals that are the subject of communication are weak signals in the high frequency band. SOLUTION TO THE PROBLEM

[0009] An embodiment of the present invention is a communication device including a sensor attached to a detection object and outputting an analog detection signal, and a modulated laser generating device that generates a modulated laser by subjecting a laser fundamental wave to modulation processing based on the analog detection signal. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0010] According to the embodiment of the present invention, a modulated laser generating device constituting a communication device generates a modulated laser. Accordingly, by performing transmission through a modulated laser, the effects of noise are less easily perceived compared to transmission through radio waves. As a result, even when the analog detection signals that are the subject of communication are weak signals in the high-frequency band, transmission can be performed with the effects of noise less easily perceived.

[0011] Furthermore, the modulated laser generated as a transmission signal is generated by subjecting the fundamental laser wave to modulation processing based on the analog detection signals output from the sensor. That is, the modulated laser is a fundamental laser wave that has undergone analog modulation processing. Accordingly, the communication device can utilize a simple configuration and be designed at a low cost. Furthermore, A / D conversion of the analog detection signals is not required, and accordingly, an A / D converter is not required. Thus, the communication device can be designed at a low cost in this respect as well.

[0012] As described above, according to the above embodiment, a communication device can be provided which is less susceptible to noise and can communicate inexpensively even when the analog detection signals which are the subject of communication are weak signals in the high frequency band.

[0013] The symbols in parentheses in the claims indicate a correlation with specific means described in the embodiments below and are not intended to limit the technical scope of the present invention. BRIEF DESCRIPTION OF THE DRAWING Fig. 1 shows a plan view of a grinding machine according to a first embodiment. Fig. Figure 2 shows a diagram showing positions in a diagram indicating the AE frequency and AE amplitude for each type of wear during grinding. Fig. 3 shows an axial cross-sectional view of a portion of the communication device (disk headstock and detection unit) in the grinding machine according to the first embodiment. Fig. 4 is a diagram illustrating the functions of each component of the communication device according to the first embodiment. Fig. 5 is a diagram showing a relationship of the ratio of the AE signal SA1 and the demodulated AE signal SA2 at modulation frequencies of a modulated laser. Fig. 6 is a diagram illustrating the functions of each component of a communication device according to a second embodiment. Fig. 7 is a diagram illustrating the functions of each component of a communication device according to a third embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS (First Embodiment)

[0014] Below, a case where a communication device 100 is applied to a grinding machine 1 will be described. However, it should be noted that the grinding machine 1 is merely an example of an application object of the communication device 100, and the communication device 100 can also be applied to various types of machine tools other than the grinding machine 1. Furthermore, in addition to machine tools, the communication device 100 can be applied to various types of industrial machines and other devices that perform wireless communication. 1. Configuration of the grinding machine 1

[0015] A configuration of the grinding machine 1 is shown with reference to Fig. 1. The grinding machine 1 rotates a workpiece W, rotates a grinding wheel T, and also moves the grinding wheel T relative to the workpiece W, thereby grinding the workpiece W. For example, the grinding machine 1 performs plunge grinding of the workpiece W by moving the grinding wheel T relative to the workpiece W to approach the workpiece W in a direction intersecting a rotational axis line of the workpiece W. The grinding machine 1 also performs longitudinal grinding on the workpiece W by moving the grinding wheel T relative to the workpiece W in a direction parallel to the rotational axis line of the workpiece W.

[0016] The grinding machine 1 is applicable to a table-type traverse grinder, a disk-head traverse grinder, etc. Furthermore, the grinding machine 1 is applicable to a cylindrical grinder, a cam grinder, etc. In the present embodiment, a table-type traverse cylindrical grinder is exemplified as the grinding machine 1. That is, the grinding machine 1 is configured to move the workpiece W in an axial line direction of the workpiece W and also to move the grinding wheel T in a direction intersecting the axial line of the workpiece W. Furthermore, in the following description, an X-axis direction indicates a direction perpendicular to the axial line of the workpiece W, and a Z-axis direction indicates a direction parallel to the axial line of the workpiece W.

[0017] The grinding machine 1 includes a bed 10, a table 20, a spindle device 30, a tailstock device 40, a disk headstock 50, a detection unit 60, a size measuring device 70, and a control device 80. Note that, in the present embodiment, the disk headstock 50, the detection unit 60, and a surface texture estimation unit (described later) of the control device 80 constitute the communication device 100.

[0018] The bed 10 is installed on an installation surface. The bed 10 is formed, for example, in the shape of an inverted T. That is, the bed 10 is formed such that it has a larger width (length in the Z-axis direction) at a front side (lower side in Fig. 1) in the X-axis direction and a smaller width at a back side (upper side in Fig. 1) in the X-axis direction.

[0019] The bed 10 includes a Z-axis guide surface 11 extending in the Z-axis direction on an upper surface on the front side in the X-axis direction. The bed 10 further includes a Z-axis drive mechanism 12 driven along the Z-axis guide surface 11. The present embodiment illustrates a case where the Z-axis drive mechanism 12 includes a ball screw mechanism 12a and a Z-axis motor 12b. Note that, instead of the above-described configuration with the ball screw mechanism 12a, a linear motor may be applied to the Z-axis drive mechanism 12.

[0020] The bed 10 also includes a guide surface 13 extending in a direction intersecting the Z-axis direction on the upper surface on the back side in the X-axis direction. In the present embodiment, the guide surface 13 is an X-axis guide surface extending in the X-axis direction orthogonal to the Z-axis. The bed 10 further includes an X-axis drive mechanism 14 driven along the X-axis guide surface 13. The present embodiment illustrates a case where the X-axis drive mechanism 14 includes a ball screw mechanism 14a and an X-axis motor 14b. Note that, instead of the above-described configuration with the ball screw mechanism 14a, a linear motor may be applied to the X-axis drive mechanism 14.

[0021] The table 20 is elongated and supported on the Z-axis guide surface 11 of the bed 10 so as to be movable in the Z-axis direction (horizontal right-left direction). Furthermore, the table 20 is fixed to a ball screw nut of the Z-axis ball screw mechanism 12a and is moved in the Z-axis direction by rotational drive of the Z-axis motor 12b.

[0022] The spindle device 30 supports the workpiece W and rotates the workpiece W. The spindle device 30 is arranged on the table 20 at one end thereof in the Z-axis direction. The spindle device 30 includes a spindle housing 31, a spindle 32, a spindle motor 33, a center member 34, and a drive force transmission mechanism 35.

[0023] The spindle housing 31 is mounted on the table 20. The spindle 32 is rotatably supported in the spindle housing 31 via bearings. The spindle motor 33 drives the spindle 32 to rotate. The center member 34 supports an end surface of the workpiece W at one end in the axial direction. The center member 34 can be fixed to the spindle housing 31 in such a way that it is non-rotatable, or it can be fixed to the spindle 32 in such a way that it is rotatable relative to the spindle housing 31.

[0024] The drive force transmission mechanism 35 is provided on an end surface in the axial direction of the spindle 32 and transmits the rotational drive force of the spindle 32 to the workpiece W, thereby rotating the workpiece W. The drive force transmission mechanism 35 is, for example, a rotary member provided at a position eccentric with respect to the axis line of the spindle 32. In other words, the rotary member serving as the drive force transmission mechanism 35 is an eccentric drive pin extending in the axial direction of the spindle 32 from the end surface of the spindle 32. The rotary member rotates around the axis line of the spindle 32 due to the rotation of the spindle 32.In the present embodiment, the rotary member serving as the driving force transmission mechanism 35 rotates the workpiece W around the axis line of the spindle 32 by meshing with a carrier Wa attached to the workpiece W in a rotational direction.

[0025] The tailstock device 40 is arranged on the table 20 on the other end side in the Z-axis direction. The tailstock device 40 includes a center member 41. The center member 41 supports an end surface of the workpiece W on its other end in the axial direction. The center member 41 can be provided in a non-rotatable manner or in a rotatable manner.

[0026] The disk headstock 50 houses the grinding wheel T and rotates the grinding wheel T. In addition to the grinding wheel T, the disk headstock 50 includes a disk headstock main body 51, a grinding wheel spindle unit 52, a grinding wheel motor 53, and a grinding wheel cover 54.

[0027] The grinding wheel T is disc-shaped. The grinding wheel T is used for grinding the outer peripheral surface of the workpiece W. The grinding wheel T consists of a plurality of abrasive grains fixed with a bonding agent. The abrasive grains used are general abrasive grains made of ceramic materials such as aluminum oxide and silicon carbide, and superabrasive grains such as diamond and CBN, among others.

[0028] The disk headstock main body 51 is rectangular in shape, for example, and is supported on the X-axis guide surface 13 of the bed 10 so as to be movable in the X-axis direction (horizontal front-to-back direction). Furthermore, the disk headstock main body 51 is fixed to a ball screw nut of the X-axis ball screw mechanism 14a and is moved in the X-axis direction by rotational drive of the X-axis motor 14b. Furthermore, the disk headstock main body 51 has a cylindrical portion that serves as a shaft housing toward the front in the X-axis direction.

[0029] The grinding wheel spindle unit 52 is rotatably supported by the cylindrical portion of the wheel headstock main body 51 via bearings (not shown in the figure). The grinding wheel spindle unit 52 holds the grinding wheel T, and the grinding wheel T rotates together with the grinding wheel spindle unit 52. The grinding wheel motor 53 rotates the grinding wheel spindle unit 52. The grinding wheel motor 53 transmits the rotational drive force to the grinding wheel spindle unit 52 via a belt, for example. However, it should be noted that the grinding wheel motor 53 may be arranged concentrically with the grinding wheel spindle unit 52.

[0030] The grinding wheel cover 54 is non-rotatably mounted on the disk headstock main body 51 and covers a portion of the grinding wheel T. The grinding wheel cover 54 is open at least in a region facing the workpiece W side (front side in the X-axis direction) to expose the grinding wheel T.

[0031] The detection unit 60 is attached to the grinding wheel T or the grinding wheel spindle unit 52, which are detection objects, and includes a sensor S that outputs analog detection signals. In the present embodiment, the sensor S is an AE sensor that detects elastic waves generated on the grinding wheel T by grinding the workpiece W with the grinding wheel T and outputs AE signals as analog detection signals. Hereinafter, the sensor S is referred to as AE sensor S. The detection unit 60 can perform wireless communication of the analog detection signals output from the AE sensor S.

[0032] The size measuring device 70 is provided on top of the bed 10 and measures the outer diameter dimensions of the workpiece W. The size measuring device 70 includes, for example, a pair of measuring needles that can come into contact with the outer peripheral surface of the workpiece W and measure the outer diameter dimensions of the workpiece W at the contact area.

[0033] The control device 80 is a CNC device that performs machining control. That is, the control device 80 performs position control of the table 20 and the disk headstock 50 by driving the Z-axis drive mechanism 12 and the X-axis drive mechanism 14, which serve as moving devices, based on a machining program and measurement results from the size measuring device 70. That is, the control device 80 moves the workpiece W and the grinding wheel T relative to each other so that they approach and separate from each other by controlling the positions of the table 20, the disk headstock 50, and so on. Further, the control device 80 controls the spindle device 30 and the disk headstock 50. That is, the control device 80 performs rotation control of the spindle 32 and rotation control of the grinding wheel T.

[0034] In addition, the control device 80 can estimate the surface texture of the workpiece W based on the AE signals detected by the AE sensor S constituting the detection unit 60, and perform machining control based on the estimated surface texture of the workpiece W. For example, the control device 80 can determine whether the workpiece W is a defect-free part by estimating the machining quality of the workpiece W based on the estimated surface texture of the workpiece W, or it can thereby estimate the surface condition of the grinding wheel T. The estimation results of the surface condition of the grinding wheel T can also be used to determine the timing for dressing the grinding wheel T or the timing for replacing the grinding wheel T. 2. Wear during grinding

[0035] Wear that occurs during grinding is to be considered with reference to Fig. 2. Grinding with the grinding machine 1 is a phenomenon in which the relatively soft workpiece W is machined in minute amounts by hard abrasive grains that make up the grinding wheel T. Grinding has been shown to be a composite phenomenon that includes abrasive wear and severe wear. The AE sensor S of the grinding machine 1 detects elastic waves caused by wear during grinding and outputs AE signals as analog detection signals. Each type of wear is expressed by a relationship between a frequency of AE signals and an amplitude of AE signals.

[0036] As in Fig. As shown in Figure 2, the frequency of the AE signals is 0.1 MHz to 0.3 MHz for light wear, 0.3 MHz to 1.1 MHz for abrasive wear, and 0.9 MHz to 1.6 MHz for heavy wear. The amplitude of AE signals is relatively small for light and abrasive wear and large for heavy wear. 3. Configuration of the communication device 100

[0037] A configuration of the communication device 100 is described with reference to Fig. 3. The communication device 100 includes the disk spindle 50, the detection unit 60, and a portion of the control device 80 (such as a surface texture estimation unit 81, etc., described below). Fig. 3 shows a portion of the disk spindle 50 and the detection unit 60. The communication device 100 includes the AE sensor S and performs wireless communication of AE signals output from the AE sensor S. The communication device 100 estimates the surface texture of the workpiece W based on, for example, the AE signals.

[0038] As described above, the disk headstock 50 includes the grinding wheel T, the disk headstock main body 51, the grinding wheel spindle unit 52, the grinding wheel motor 53, and the grinding wheel cover 54. The grinding wheel spindle unit 52 includes a grinding wheel spindle 52a and a fixing member 52b. The grinding wheel spindle 52a is shaft-shaped and is rotatably supported by bearings through the cylindrical portion of the disk headstock main body 51. The grinding wheel T is fitted onto a distal end of the grinding wheel spindle 52a. The fixing member 52b is a member for holding the grinding wheel T by clamping it in the axial direction to the distal end of the grinding wheel spindle 52a. Accordingly, the grinding wheel T, the grinding wheel spindle 52a, and the fixing member 52b rotate as a unit.

[0039] The detection unit 60 includes a first unit 61 and a second unit 62. The first unit 61 is attached to the grinding wheel spindle unit 52 or the grinding wheel T, which are detection objects. The grinding wheel spindle unit 52 and the grinding wheel T are rotating bodies that rotate integrally around a rotation center line Ct. Therefore, the first unit 61 rotates together with the grinding wheel spindle unit 52 and the grinding wheel T around the rotation center line Ct. The second unit 62 is attached to the grinding wheel cover 54 or to a member integral with the grinding wheel cover 54. For example, the second unit 62 is attached to the wheel headstock main body 51 or the grinding wheel cover 54. In other words, the first unit 61 rotates relative to the second unit 62 around the rotation center line Ct.

[0040] The first unit 61 includes a first unit housing 101, the AE sensor S, a power supply unit 102, a modulated laser generating device 103, a fixing screw 104, and a power receiving coil 105.

[0041] The housing of the first unit 101 is cylindrically shaped with a bottom. An outer bottom surface of the housing of the first unit 101 is attached to an axial direction end surface of the grinding wheel spindle unit 52, so that the housing of the first unit 101 and the grinding wheel spindle unit 52 are concentric. In detail, the housing of the first unit 101 is attached to an axial direction end surface of the fixing member 52b, that is, an opening side of the housing of the first unit 101 is located on a side opposite the grinding wheel spindle unit 52.

[0042] The AE sensor S, the power supply unit 102, the modulated laser generating device 103, and the fixing screw 104 are housed in the cylindrical interior of the housing of the first unit 101. As described above, the AE sensor S detects elastic waves generated on the grinding wheel T when the workpiece W is ground by the grinding wheel T and outputs AE signals as analog detection signals. The AE sensor S detects elastic waves caused by slight wear, abrasive wear, and heavy wear and outputs AE signals SA1 as analog detection signals. The AE sensor S is mounted on a central recessed portion located on a bottom surface of the housing of the first unit 101 on the rotation center line Ct.

[0043] The power supply unit 102 includes a storage battery and a power receiving circuit and is provided on a lower end face of the housing of the first unit 101. The power supply unit 102 supplies electrical drive power to the AE sensor S and the modulated laser generating device 103.

[0044] The modulated laser generating device 103 is arranged closer to the opening side of the casing of the first unit 101 than the power supply unit 102 and is stacked on the power supply unit 102. The modulated laser generating device 103 subjects fundamental laser waves to modulation processing based on the AE signals SA1 output from the AE sensor S, thereby generating a modulated laser SL. The modulated laser generating device 103 generates the modulated laser SL toward the opening side of the casing of the first unit 101 along the rotation center line Ct.

[0045] The modulated laser SL may be a laser in which the laser fundamental waves are subjected to amplitude modulation processing or a laser in which the laser fundamental waves are subjected to frequency modulation processing.

[0046] The modulated laser generating device 103 is configured to generate, for example, semiconductor lasers. The modulated laser generating device 103 may employ a configuration that generates vertical cavity surface-emitting lasers or a configuration that generates, for example, edge-emitting lasers. For the modulated laser generating device 103, an arrangement having, for example, a laser bandwidth of 4 GHz and an emission wavelength of approximately 850 nm is used. By using this configuration, the modulated laser generating device 103 can generate a modulated laser that includes abrasive wear and severe wear components. However, it should be noted that the modulated laser generating device 103 is not limited to this configuration. For example, an arrangement having an emission wavelength of 400 nm to 800 nm may be used.

[0047] The fixing screw 104 is screwed into an inner peripheral surface of the first unit housing 101 and holds the power supply unit 102 and the modulated laser generating device 103 in an axially intermediate state. The fixing screw 104 has a through-hole at its center along the rotational centerline Ct. This through-hole is sized to allow the modulated laser SL to pass through.

[0048] The power receiving coil 105 is arranged at an open end of the housing of the first unit 101. The power receiving coil 105 is a contactless power supply coil and is connected to a power receiving circuit of the power supply unit 102. The electrical energy obtained via the power receiving coil 105 is stored in the storage battery of the power supply unit 102. Furthermore, a through-hole is formed in the center of the power receiving coil 105 along the rotation center line Ct. This through-hole is sized to allow the modulated laser SL to pass through.

[0049] Now, the power supply unit 102 and the power receiving coil 105 are provided integrally with the modulated laser generating device 103, forming a non-contact power receiving unit configured to supply electrical power to the AE sensor S and the modulated laser generating device 103. The non-contact power receiving unit is not limited to a configuration including the power receiving coil 105, and other configurations may be used as long as the non-contact power receiving unit is capable of non-contact power reception.

[0050] The second unit 62 includes a unit cover 111, a second unit casing 112, a power supply unit 113, a laser receiving device 114, and a power supply coil 115.

[0051] The unit cover 111 is attached to the disk headstock main body 51 or to the grinding wheel cover 54. Accordingly, the unit cover 111 is provided in a non-rotatable manner. In the present embodiment, the unit cover 111 is attached to the grinding wheel cover 54. The unit cover 111 accommodates other elements 112, 113, 114, and 115 that constitute the second unit 62.

[0052] The housing of the second unit 112 is attached to the unit cover 111 and is arranged to face the first unit 61 in the direction of the rotation center line Ct. The housing of the second unit 112 is cylindrical with a bottom and is arranged so that its opening side faces the side of the first unit 61.

[0053] The power supply unit 113 includes a power supply circuit and is provided on a lower end side of the cylindrical interior of the housing of the second unit 112.

[0054] The laser receiving device 114 is housed within the cylindrical casing of the second unit 112. Accordingly, the laser receiving device 114 is provided so as to be non-rotatable and is arranged to face the modulated laser generating device 103 in the direction of the rotation center line Ct. The laser receiving device 114 receives the modulated laser SL generated by the modulated laser generating device 103. Specifically, the laser receiving device 114 receives a modulated laser generated along the rotation center line Ct. The laser receiving device 114 then demodulates the received modulated laser SL to generate demodulated analog signals SA2. Hereinafter, the demodulated analog signals SA2 are referred to as demodulated AE signals.

[0055] For example, a high-speed Si photodiode is used for the laser receiving device 114. The sensitivity of the laser receiving device 114 is 2 GHz, for example. By using this configuration, the laser receiving device 114 can generate demodulated AE signals SA2 that include abrasive wear and severe wear components. However, it should be noted that the laser receiving device 114 is not limited to this configuration.

[0056] The modulated laser SL is generated by the rotating modulated laser generating device 103 of the first unit 61 and is received by the laser receiving device 114 of the non-rotatable second unit 62. Now, the modulated laser SL is generated along the rotation center line Ct, and accordingly, the position of the modulated laser SL will not deviate significantly. Thus, the laser receiving device 114 can reliably receive the modulated laser generated by the rotating modulated laser generating device 103.

[0057] The power supply coil 115 is arranged at an open end of the housing of the second unit 112. The power supply coil 115 is a coil for performing contactless power supply and is connected to the power supply circuit of the power supply unit 113. The power supply coil 115 faces the power receiving coil 105 but is spaced apart from it. Furthermore, a through-hole is formed in the center of the power supply coil 115 along the rotation center line Ct. This through-hole is sized to allow the modulated laser SL to pass through.

[0058] Now, the power supply unit 113 and the power supply coil 115 are integrally provided in the laser receiving device 114, forming a non-contact power supply unit configured to contactlessly supply power to the power supply unit 102 and the power receiving coil 105, which serve as a non-contact power receiving unit constituting the first unit 61. The non-contact power receiving unit is not limited to a configuration including the power supply coil 115, and other configurations may be used as long as they enable contactless power supply. 4. Functional configuration of the communication device 100

[0059] A functional configuration of the communication device 100 is described with reference to Fig. 4. As described in Fig. As shown in Figure 4, the AE sensor S outputs AE signals SA1, which are analog detection signals. The AE signals SA1 are signals based on elastic waves caused by slight wear, abrasive wear, and heavy wear.

[0060] The AE signals SA1 are converted into modulated lasers SL in the modulated laser generating device 103. Fig. 4, the modulated laser SL is a laser in which the fundamental laser waves undergo amplitude modulation processing based on the AE signals SA1. That is, the frequency of the modulated laser SL is the same as that of the fundamental laser waves, and the amplitude of the modulated laser SL has a magnitude corresponding to the AE signals SA1.

[0061] Specifically, a modulation frequency band of the modulated laser SL is arranged to include a frequency band of at least 1.0 MHz or higher. More preferably, the modulation frequency band of the modulated laser SL includes any frequency band in at least a range of 1.0 MHz to 2.0 MHz. Accordingly, the modulated laser SL can transmit the abrasive wear and severe wear components more securely. In the present embodiment, the modulation frequency band of the modulated laser SL includes any frequency band of 1.0 MHz or higher and any frequency band in a range of 50 kHz to 500 kHz. Therefore, the modulated laser SL can transmit the abrasive wear and severe wear components more securely. For example, the modulation frequency band of the modulated laser SL is set to 300 kHz to 1.8 MHz or the like.

[0062] The modulated laser SL is generated by the modulated laser generating device 103 of the first unit 61, which rotates, and received by the laser receiving device 114 of the second unit 62, which is provided in a non-rotatable manner. The use of the modulated laser SL enables wireless communication between the modulated laser generating device 103 and the laser receiving device 114. Furthermore, the modulated laser SL is generated along the rotation center line Ct, as described with reference to Fig. 3. Accordingly, even if the modulated laser generating device 103 and the laser receiving device 114 rotate relative to each other, the position of the generated modulated laser SL does not deviate significantly, and the laser receiving device 114 can reliably receive the modulated laser.

[0063] The control device 80 is equipped with the surface texture estimation unit 81. The surface texture estimation unit 81 acquires the demodulated AE signals SA2 and estimates the surface texture of the workpiece W based on the demodulated AE signals SA2. The AE signals SA1 contain components of light wear, abrasive wear, and heavy wear, and the modulated laser SL is a laser that contains components of abrasive wear and heavy wear. The demodulated AE signals SA2 are thus signals that retain the components of abrasive wear and heavy wear. Accordingly, by performing analysis using the demodulated AE signals SA2, the composite phenomenon of abrasive wear and heavy wear can be understood and the surface texture of the workpiece W can be estimated.

[0064] Note that the control device 80 may use the estimation results of the surface texture estimation unit 81 to determine whether the workpiece W is defect-free or defective. Although an example is described in which the control device 80 includes the surface texture estimation unit 81, a calculation processing device different from the control device 80 may include the surface texture estimation unit 81. 5. Relationship between AE signals SA1 and demodulated AE signals SA2

[0065] A relationship between the AE signals SA1 and the demodulated AE signals SA2 is described with reference to Fig. 5. As described above, the AE signals SA1 are converted into the modulated laser SL, and the modulated laser SL is used to generate the demodulated AE signals SA2. That is, the AE signals SA1 and the demodulated AE signals SA2 are signals converted via the modulated laser SL.

[0066] In addition, a ratio (SA1 / SA2) of the AE signals SA1 and the demodulated AE signals SA2 varies depending on the modulation frequency of the modulated laser. This relationship is shown in Fig. 5. Now the modulation frequency corresponds to the frequency of the AE signals SA1.

[0067] At Fig. 5, the vertical axis (unit [dB]) indicates the base 10 logarithm of the ratio of the AE signals SA1 and the demodulated AE signals SA2. That is, 0 on the vertical axis corresponds to a ratio of 1 between the AE signals SA1 and the demodulated AE signals SA2. Accordingly, Fig. 5, when the modulation frequency is in the range of 100 kHz to 1.0 MHz, the ratio of the AE signals SA1 and the demodulated AE signals SA2 is 1. However, depending on the configuration of the communication device 100, there are cases where this ratio takes a value other than 1, even if there is a range in which the ratio of the AE signals SA1 and the demodulated AE signals SA2 has an approximately constant value.

[0068] As in Fig. As shown in Figure 5, the ratio of the AE signals SA1 and the demodulated AE signals SA2 is within a predetermined tolerance range when the modulation frequency is in a range Δf from 50 kHz to 2.0 MHz. The term tolerance range used here means a predetermined range in a case where the variance is taken into account. That is, the modulation frequency in the range Δf from 50 kHz to 2.0 MHz is a frequency band in which the ratio of the AE signals SA1 before modulation processing and the demodulated AE signals SA2 has a substantially constant value (approximately 1.0 dB in Fig. 5). This means that the modulation frequency in the range Δf from 50 kHz to 2.0 MHz has sufficient linearity. It should be noted that, as in Fig. 5, in the modulation frequency in the range of 80 kHz to 1.5 MHz, the ratio of the AE signals SA1 before modulation processing and the demodulated AE signals SA2 is contained in a minimum range and has extremely high linearity.

[0069] In a case where the ratio between the AE signals SA1 and the demodulated AE signals SA2 happens to be substantially 1 (0 dB), the AE signals SA1 and the demodulated AE signals SA2 are substantially the same when the modulation frequency is in the range Δf of 50 kHz to 2.0 MHz. However, even if this ratio is not 1, as long as the ratio is within the range Δf of the modulation frequency, the AE signals SA1 and the demodulated AE signals SA2 have a certain relationship, so it is within the predetermined tolerance range, and accordingly, the AE signals SA1 can be estimated from the demodulated AE signals SA2.

[0070] Furthermore, the modulation frequency band of the range Δf from 50 kHz to 2.0 MHz, in which the ratio of the AE signals SA1 before modulation processing and the demodulated AE signals SA2 has a substantially constant value, includes the frequency bands for abrasive wear and heavy wear (see Fig. 2). It is therefore evident that the abrasive wear and severe wear components can be transferred using the modulated laser SL. 6. Effects of the embodiment

[0071] According to the communication device 100 of the present embodiment, the modulated laser generating device 103 constituting the communication device 100 generates modulated laser SLs. Accordingly, by performing transmission by modulated laser SLs, the effects of noise are less easily received than in radio wave transmission. As a result, even if the analog detection signals (AE signals) SA1 that are the subject of communication are weak signals in the high frequency band, their transmission can be performed without being easily affected by noise.

[0072] Furthermore, the modulated laser SL generated as transmission signals is generated by subjecting the fundamental laser waves to modulation processing based on the AE signals SA1 output from the AE sensor S. That is, the modulated laser SL consists of fundamental laser waves subjected to analog modulation processing. Accordingly, a simple configuration can be adopted for the communication device 100, which can be manufactured inexpensively. Since no A / D conversion of the AE signals SA1, which are analog detection signals, is required, no A / D converter is needed. Therefore, the communication device 100 can be manufactured inexpensively in this respect as well.

[0073] Thus, according to the communication device 100 of the present embodiment, although the AE signals SA1, which are analog detection signals of the communication object, are weak signals in a high frequency band, the effects of noise are less easily received, and also the communication can be performed inexpensively.

[0074] Furthermore, the laser receiving device 114 constituting the communication device 100 receives the modulated laser SL generated by the modulated laser generating device 103 and generates demodulated analog signals (demodulated AE signals) SA2 by subjecting the modulated laser SL to demodulation processing. This enables the communication device 100 to transmit and receive the AE signals SA1 via the modulated laser SL.

[0075] The modulated laser generating device 103 performs amplitude modulation processing as modulation processing. By applying amplitude modulation processing, fundamental laser waves can be easily and safely subjected to modulation processing based on the AE signals SA1. Furthermore, the AE sensor S is mounted on the grinding wheel T or the grinding wheel spindle unit 52, which is a rotating body that is a detection object. The modulated laser generating device 103 is arranged at one end of the grinding wheel T in the axial direction and the grinding wheel spindle unit 52, and generates a modulated laser SL along the rotation center line Ct. Although the modulated laser generating device 103 is mounted on the rotating body, generating the modulated laser SL along the rotation center line Ct prevents positional deviation of the modulated laser SL.Accordingly, the modulated laser SL can be transmitted at a stable position.

[0076] The laser receiving device 114 is arranged non-rotatably and faces the modulated laser generating device 103 in the direction of the rotation center line Ct, and receives the modulated laser SL generated along the rotation center line Ct. That is, even when the modulated laser generating device 103 and the laser receiving device 114 rotate relative to each other, the laser receiving device 114 can reliably receive the modulated laser SL.

[0077] The AE sensor S is mounted on the grinding wheel T or the grinding wheel spindle unit 52, detects elastic waves generated on the grinding wheel T, and outputs AE signals as analog detection signals. This allows the grinding phenomenon to be reliably analyzed.

[0078] Furthermore, the AE sensor S is mounted on the grinding wheel T or the grinding wheel spindle unit 52 to detect elastic waves generated on the grinding wheel T and output AE signals, and the laser receiving device 114 is mounted on the grinding wheel cover 54. By employing such a mounting relationship, the AE sensor S, the modulated laser generating device 103, and the laser receiving device 114 can be mounted at desired positions.

[0079] In the present embodiment, the AE sensor S also detects elastic waves caused by abrasive wear or severe wear during grinding and outputs AE signals SA1. Furthermore, the laser receiving device 114 generates demodulated AE signals SA2 containing components of abrasive wear or severe wear. Accordingly, the grinding phenomenon can be reliably detected.

[0080] Furthermore, the modulation frequency band of the modulated laser SL preferably includes a frequency band of at least 1.0 MHz or higher. More preferably, the modulation frequency band of the modulated laser SL includes any frequency band in at least a range of 1.0 MHz to 2.0 MHz. Even in such a high frequency band, the AE signals SA1 are not easily affected by noise, and accordingly, communication of the high frequency band AE signals SA1 can be performed securely. Furthermore, the modulation frequency band of the modulated laser SL preferably includes a frequency band of 1.0 MHz or higher and any frequency band in the range of 50 kHz to 500 kHz. By including a low frequency band in addition to a high frequency band in this way, the grinding phenomenon can be securely understood.

[0081] In particular, the modulation frequency band of the modulated laser SL is preferably a frequency band in which the ratio (SA1 / SA2) of the AE signals SA1 before modulation processing and the demodulated AE signals SA2 after demodulation processing has a substantially constant value. This makes it possible to detect the state of the AE signals SA1 with high accuracy using the demodulated AE signals SA2.

[0082] Further, the surface texture estimation unit 81 estimates the surface texture of the workpiece W ground by the grinding wheel T based on the demodulated AE signals SA2. Abrasive wear and severe wear can be detected based on the demodulated AE signals SA2, and accordingly, the surface texture of the workpiece W estimated using the demodulated AE signals SA2 can be estimated with high accuracy.

[0083] Furthermore, the detection unit 60 includes the first unit 61, which is rotatable, and the second unit 62, which is non-rotatable. The first unit 61 is equipped with the AE sensor S and the modulated laser generating device 103, and further includes the non-contact power receiving units (102, 105) that are provided integrally with the modulated laser generating device 103 and are configured to supply electrical power to the AE sensor S. On the other hand, the second unit 62 is equipped with the laser receiving device 114 and further includes the non-contact power supplying units (113, 115) that are provided integrally with the laser receiving device 114 and are configured to contactlessly supply power to the non-contact power receiving units (102, 105).Accordingly, although the AE sensor S and the modulated laser generating device 103 are provided at the first unit 61 which rotates, electric power can be supplied thereto. (Second embodiment)

[0084] A communication device 200 according to the present embodiment is mainly described with reference to Fig. 6 and additionally with reference to Fig. 5. The communication device 200 according to the present embodiment differs from the communication device 100 according to the first embodiment with respect to the configuration of a laser receiving device 214. The laser receiving device 214 is described below. Note that, among the symbols or reference numerals used in the second and subsequent embodiments, those that are the same as those used in the previous embodiments represent the same components or the like as in the previous embodiments unless otherwise noted.

[0085] The laser receiving device 214 receives the modulated laser SL generated by the modulated laser generating device 103 and generates demodulated AE signals SA2. In the present embodiment, Fig. 5, the ratio of the AE signals SA1 and the demodulated AE signals SA2 has a substantially constant value of 1 (0 dB) when the modulation frequency is between 50 kHz and 2.0 MHz. In a case where the ratio is not 1 (0 dB), the AE signals SA1 and the demodulated AE signals SA2 have a certain relationship but do not agree.

[0086] Accordingly, in the present embodiment, the laser receiving device 214 corrects the demodulated AE signals SA2 such that the demodulated AE signals SA2 match the AE signals SA1, even if this ratio is in Fig. 5 is not 1.

[0087] In this case, as in Fig. As shown in Figure 6, the laser receiving device 214 includes a receiving unit 201, a demodulation processing unit 202, and a correction unit 203. The receiving unit 201 receives the modulated laser SL. The demodulation processing unit 202 performs demodulation processing on the received modulated laser SL to generate uncorrected demodulated AE signals. The correction unit 203 corrects the uncorrected demodulated AE signals, which are demodulated, to generate corrected demodulated AE signals SA2. Even if the uncorrected demodulated AE signals do not match the AE signals SA1, the corrected demodulated AE signals SA2 can be adjusted to match the AE signals SA1.

[0088] According to the present embodiment, the corrected demodulated AE signals SA2 match the AE signals SA1, and accordingly, high-precision processing can be achieved in processing using the corrected demodulated AE signals SA2. For example, in a case where the surface texture estimation unit 81 estimates the surface texture of the workpiece W, the surface texture of the workpiece W can be estimated with high accuracy. (Third embodiment)

[0089] A communication device 300 according to the present embodiment is described with reference to Fig.7. The communication device 300 according to the present embodiment differs from the communication device 100 according to the first embodiment with respect to the configurations of a modulated laser generating device 301 and a laser receiving device 302. The modulated laser generating device 301 and the laser receiving device 302 are described below.

[0090] The modulated laser generating device 301 generates the modulated laser SL by subjecting a fundamental laser wave to frequency modulation processing based on the AE signals SA1. That is, the modulated laser SL has an amplitude that is constant with respect to the fundamental laser wave, but has a different frequency. The laser receiving device 302 then receives the modulated laser SL and subjects the modulated laser SL to demodulation processing to generate demodulated AE signals SA2. The demodulation processing at the laser receiving device 302 is frequency demodulation processing according to the present embodiment.

[0091] The present embodiment also achieves the same effects as the first embodiment. However, it should be noted that amplitude modulation processing produces a modulated laser more easily than frequency modulation. Accordingly, the amplitude modulation according to the first embodiment enables the simpler production of a modulated laser. (Other)

[0092] In the above-described embodiments, examples are described of cases where the communication devices 100, 200, and 300 are applied to the grinding machine 1. However, the communication devices 100, 200, and 300 can also be applied to devices other than the grinding machine 1. For example, the application can be applied to machine tools other than the grinding machine 1 and also to other industrial machines.

[0093] In the above embodiments, the AE sensor S was described as an example of a sensor that outputs analog detection signals. However, any sensor other than the AE sensor S can be used as long as it outputs analog detection signals. This is particularly useful when wireless communication of analog detection signals is to be performed in a high-frequency band of 1.0 MHz or higher. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2021 / 153042

[0003] JP 2022–36928 A

[0003]

Claims

[1] Communication device (100, 200, 300), comprising: a sensor (S) attached to a detection object (52, T) and outputting an analog detection signal (SA1); and a modulated laser generating device (103, 301) that generates a modulated laser (SL) by subjecting a fundamental laser wave to modulation processing based on the analog detection signal. [2] A communication device according to claim 1, further comprising a laser receiving device (114, 214, 302) that receives the modulated laser generated by the modulated laser generating device and generates a demodulated analog signal (SA2) by subjecting the modulated laser to demodulation processing. [3] The communication device according to claim 1 or 2, wherein the modulated laser generating device performs amplitude modulation processing as the modulation processing. [4] Communication device according to claim 1 or 2, wherein the detection object is a rotating body, and the modulated laser generating device is arranged at an axial direction end of the rotating body and generates the modulated laser along a rotation center line (Ct) of the rotating body. [5] A communication device according to claim 2, wherein the detection object is a rotating body, the modulated laser generating device is arranged at an axial direction end of the rotating body and generates the modulated laser along a rotation center line (Ct) of the rotating body, and the laser receiving device is provided non-rotatably, the modulated laser generating device is arranged facing in a direction of the rotation center line of the rotating body and receives the modulated laser generated along the rotation center line of the rotating body. [6] The communication device of claim 1, further comprising: a grinding wheel (T) for grinding a workpiece (W); and a grinding wheel spindle unit (52) holding the grinding wheel, wherein the sensor is an AE sensor mounted on the grinding wheel or the grinding wheel spindle unit, detects an elastic wave generated on the grinding wheel, and outputs an AE signal as the analog detection signal. [7] A communication device according to claim 2, further comprising: a grinding wheel (T) for grinding a workpiece (W); a grinding wheel spindle unit (52) holding the grinding wheel; and a grinding wheel cover (54) which is provided non-rotatably and covers a portion of the grinding wheel, wherein the sensor is an AE sensor that is attached to the grinding wheel or the grinding wheel spindle unit, detects an elastic wave generated on the grinding wheel, and outputs an AE signal as the analog detection signal, and the laser receiving device is attached to the grinding wheel cover or an element formed integrally with the grinding wheel cover. [8] The communication device according to claim 6, wherein the AE sensor detects the elastic wave caused by abrasive wear or severe wear in grinding and outputs the AE signal as the analog detection signal. [9] Communication device according to claim 7, wherein the AE sensor detects the elastic wave caused by abrasive wear or heavy wear during grinding and outputs the AE signal as the analog detection signal, and the laser receiving device generates the demodulated analog signal which includes a component of abrasive wear or severe wear. [10] The communication device according to claim 1 or 2, wherein a modulation frequency band of the modulated laser includes a frequency band of at least 1.0 MHz or higher. [11] The communication device according to claim 10, wherein the modulation frequency band of the modulated laser includes the frequency band of 1.0 MHz or higher and any frequency band in a range of 50 kHz to 500 kHz. [12] A communication device according to claim 2, wherein a modulation frequency band of the modulated laser is a frequency band in which a ratio of the analog detection signal before the modulation processing and the demodulated analog signal after the demodulation processing is within a predetermined tolerance range. [13] The communication device according to claim 2, wherein the laser receiving device corrects the demodulated analog signal such that the demodulated analog signal agrees with the analog detection signal. [14] Communication device according to claim 2, wherein the detection object is a grinding wheel (T) for grinding a workpiece (W), the sensor is an AE sensor that detects an elastic wave generated at the grinding wheel and outputs an AE signal as the analog detection signal, and the communication device further includes a surface texture estimation unit (81) that estimates the surface texture of the workpiece ground by the grinding wheel based on the demodulated analog signal. [15] Communication device according to claim 2, further comprising: a contactless energy receiving unit (102, 105) provided integrally with the modulated laser generating device and adapted to supply electrical energy to the sensor; and a contactless power supply unit (113, 115) provided integrally with the laser receiving device and configured to perform contactless power supply to the contactless power receiving unit.

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