Communication device

Abstract

The invention relates to a communication device. A communication device (100) is provided with: a sensor (S) that is attached to an object to be detected (52, T) and outputs an analog detection signal (SA1); and a modulated laser beam generation device (103) that generates a modulated laser beam (SL) by performing a modulation process on the laser beam fundamental wave on the basis of the analog detection signal.

Description

Technical Field

[0001] The present invention relates to a communication device. Background Art

[0002] Patent document 1 describes a technology in which an AE sensor is mounted on a component for holding a grinding wheel in order to determine whether the grinding wheel is glazed or cracked. The AE sensor detects elastic waves generated when the grinding wheel grinds a workpiece and outputs an AE signal, which is then used as an electric wave for wireless communication.

[0003] Patent document 2 describes a communication system that uses lasers as digital signals to send and receive information data. In this communication system, information data is given to lasers by converting lasers into digital signals, using bright light as on and dim light as off, and expressing them by the length of the on time and the length of the off time. As a method of generating bright light and dim light, it is described that a laser light source is set to on / off, generating bright light when on and generating dim light when off. As another method of generating bright light and dim light, a technology of generating bright light and dim light by continuously setting a laser light source to an on state and using an optical modulator to change the intensity of the laser is also described.

[0004] Patent Document 1: International Publication No. 2021 / 153042

[0005] Patent Document 2: Japanese Patent Application Publication No. 2022-36928

[0006] In recent years, there has been an urgent desire to use information during processing to understand the surface properties of a workpiece, etc. As described in Patent Document 1, when an AE sensor installed on a member for holding a grinding wheel is used to detect the surface properties of a workpiece, it is known that a component highly correlated with the surface properties of the workpiece contained in an analog signal output from the AE sensor includes, for example, a signal in a high frequency band of 1.0 MHz or more.

[0007] However, the intensity of analog signals in the high-frequency band above 1.0 MHz is very weak. Moreover, in wireless communication using radio waves, the weak analog signals in the high-frequency band used for wireless communication are affected by various noises such as EMC noise generated from machine tools and other equipment in the factory, and switching noise generated from the power supply. As a result, it is difficult to extract the desired analog signal in the receiving device that receives the AE signal transmitted by radio waves, and appropriate data analysis cannot be performed.

[0008] Patent document 2 describes a technique of using laser light as visible light instead of radio waves. Patent document 2 describes a technique of sending laser light as an on / off digital signal. As described in patent document 2, when using laser light to communicate analog signals such as AE signals, it is necessary to convert the analog signals such as AE signals into A / D conversion and generate an on / off digital signal. Then, using the converted on / off digital signal, a laser light that switches between bright light and dark light is generated. Furthermore, in the receiving device, it is necessary to analyze the laser light of the on / off digital signal.

[0009] Here, in the receiving device, in order to analyze the analog signal of the high frequency band using the laser of the digital signal, the laser oscillator becomes expensive. As a result, even if the device described in Patent Document 2 is used, it is not easy to communicate the analog signal of the high frequency band using the laser. Summary of the invention

[0010] The present invention has been made in view of the above-mentioned problems, and provides a communication device which is not easily affected by noise and can perform communication at low cost even if the analog detection signal of the communication object is a weak signal in the high frequency band.

[0011] One embodiment of the present invention provides a communication device comprising: a sensor that is mounted on a detection object and outputs an analog detection signal; and a modulated laser generating device that generates modulated laser light by performing a modulation process on a laser fundamental wave based on the analog detection signal.

[0012] According to one embodiment of the present invention, a modulated laser generating device constituting a communication device generates a modulated laser. Therefore, the transmission of the modulated laser is less susceptible to noise than the transmission of radio waves. As a result, even if the analog detection signal of the communication object is a weak signal in the high frequency band, it can be transmitted without being affected by noise.

[0013] Furthermore, the modulated laser generated as the transmission signal is generated by performing a modulation process on the laser fundamental wave based on the analog detection signal output by the sensor. That is, the modulated laser is a laser subjected to an analog modulation process on the laser fundamental wave. Therefore, the communication device can adopt a simple structure and can become cheap. In addition, it is not necessary to perform A / D conversion on the analog detection signal, so an A / D converter is not required. Therefore, in this regard, it can also be set as a cheap communication device.

[0014] As described above, according to the above embodiment, it is possible to provide a communication device that is less susceptible to noise and can perform communication at low cost even if the analog detection signal of the communication object is a weak signal in the high frequency band.

[0015] In addition, the reference numerals in parentheses described in the claims indicate the corresponding relationship with the specific mechanisms described in the embodiments described later, and do not limit the technical scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a top view showing the grinding machine according to the first embodiment.

[0017] Figure 2 This is a diagram showing the position on a graph of AE frequency and AE amplitude for each wear in grinding.

[0018] Figure 3 This is an axial cross-sectional view of the communication device (grinding head and detection unit) portion of the grinding machine according to the first embodiment.

[0019] Figure 4 This is a diagram showing the function of each structure of the communication device according to Embodiment 1.

[0020] Figure 5 This is a diagram showing the relationship between the ratio of the AE signal SA1 and the demodulated AE signal SA2 in the modulation frequency of the modulated laser light.

[0021] Figure 6 This is a diagram showing the functions of each structure of the communication device according to the second embodiment.

[0022] Figure 7 This is a diagram showing the functions of each structure of the communication device according to the third embodiment. DETAILED DESCRIPTION

[0023] (Implementation Method 1)

[0024] Hereinafter, the case where the communication device 100 is applied to the grinding machine 1 will be described. However, the grinding machine 1 is only an example of an applicable object of the communication device 100, and the communication device 100 can also be applied to various machine tools other than the grinding machine 1. In addition, the communication device 100 can also be applied to various industrial machines and other devices that perform wireless communication in addition to machine tools.

[0025] 1. Structure of grinding machine 1

[0026] Reference Figure 1 The structure of the grinding machine 1 will be described. The grinding machine 1 grinds the workpiece W by rotating the workpiece W, rotating the grinding wheel T, and moving the grinding wheel T relative to the workpiece W. For example, the grinding machine 1 performs plunge grinding on the workpiece W by bringing the grinding wheel T relatively close to the workpiece W in a direction intersecting the rotation axis of the workpiece W. In addition, the grinding machine 1 performs transverse grinding on the workpiece W by moving the grinding wheel T relative to the workpiece W in a direction parallel to the rotation axis of the workpiece W.

[0027] The grinder 1 can be applied to a table traverse type grinder, a grinding head traverse type grinder, etc. In addition, the grinder 1 can be applied to a cylindrical grinder, a cam grinder, etc. In the present embodiment, the grinder 1 takes a table traverse type cylindrical grinder as an example. That is, the grinder 1 is a structure that moves the workpiece W in the axial direction of the workpiece W and moves the grinding wheel T in a direction intersecting the axis of the workpiece W. In addition, hereinafter, the X-axis direction represents a direction orthogonal to the axis of the workpiece W, and the Z-axis direction represents a direction parallel to the axis of the workpiece W.

[0028] The grinding machine 1 includes a bed 10, a table 20, a spindle device 30, a tailstock device 40, a grinding head 50, a detection unit 60, a sizing device 70, and a control device 80. In addition, in the present embodiment, the grinding head 50, the detection unit 60, and a surface property estimation unit (described later) of the control device 80 constitute a communication device 100.

[0029] The bed 10 is installed on the installation surface. The bed 10 is formed into an inverted T shape, for example. That is, the bed 10 has the front side ( Figure 1 The width (Z-axis length) of the lower side is formed longer, and the back side ( Figure 1 The width of the upper side) is formed shorter.

[0030] The bed 10 has a Z-axis guide surface 11 extending in the Z-axis direction on the upper surface of the front side in the X-axis direction. In addition, the bed 10 has a Z-axis drive mechanism 12 driven along the Z-axis guide surface 11. In this embodiment, the Z-axis drive mechanism 12 is taken as an example of a case where it has a ball screw mechanism 12a and a Z-axis motor 12b. In addition, the Z-axis drive mechanism 12 may also be replaced with a structure having the above-mentioned ball screw mechanism 12a and a linear motor.

[0031] In addition, the upper surface of the bed 10 on the back side in the X-axis direction is provided with a guide surface 13 extending in a direction intersecting the Z-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. In addition, the bed 10 is provided with an X-axis drive mechanism 14 driven along the X-axis guide surface 13. In the present embodiment, the X-axis drive mechanism 14 is provided with a ball screw mechanism 14a and an X-axis motor 14b as an example. In addition, the X-axis drive mechanism 14 can also replace the structure of the above-mentioned ball screw mechanism 14a with a linear motor.

[0032] The worktable 20 is formed in an elongated shape and is supported by the Z-axis guide surface 11 of the bed 10 so as to be movable in the Z-axis direction (horizontally left and right direction). In addition, the worktable 20 is fixed to the ball screw nut of the Z-axis ball screw mechanism 12a and is driven by the rotation of the Z-axis motor 12b to move in the Z-axis direction.

[0033] The spindle device 30 supports the workpiece W and rotationally drives the workpiece W. The spindle device 30 is disposed on one end side of the table 20 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 driving force transmission mechanism 35 .

[0034] The spindle housing 31 is fixed to the worktable 20. The spindle 32 is supported by the spindle housing 31 via a bearing so as to be rotatable. The spindle motor 33 drives the spindle 32 to rotate. The center component 34 supports the end surface of one axial end of the workpiece W. The center component 34 can be set to be fixed to the spindle housing 31 and cannot rotate, or it can be set to be fixed to the spindle 32 and can rotate relative to the spindle housing 31.

[0035] The driving force transmission mechanism 35 is provided on the axial end surface of the spindle 32, and rotates the workpiece W by transmitting the rotational driving force of the spindle 32 to the workpiece W. The driving force transmission mechanism 35 is, for example, a rotating component provided at a position eccentric from the axis of the spindle 32. That is, the rotating component of the driving force transmission mechanism 35 is an eccentric driving pin extending from the axial end surface of the spindle 32 to the axial direction of the spindle 32. The rotating component revolves around the axis of the spindle 32 by the rotation of the spindle 32. In the present embodiment, the rotating component of the driving force transmission mechanism 35 rotates the workpiece W around the axis of the spindle 32 by engaging with the carrier Wa mounted on the workpiece W in one rotation direction.

[0036] The tailstock device 40 is disposed on the other end side of the table 20 in the Z-axis direction. The tailstock device 40 includes a center member 41. The center member 41 supports the end surface of the other axial end of the workpiece W. The center member 41 may be provided to be non-rotatable or rotatable.

[0037] The grinding head 50 includes a grinding wheel T, and rotationally drives the grinding wheel T. The grinding head 50 includes, in addition to the grinding wheel T, a grinding head body 51 , a grinding wheel spindle unit 52 , a grinding wheel motor 53 , and a grinding wheel cover 54 .

[0038] The grinding wheel T is formed in a disc shape. The grinding wheel T is used to grind the outer peripheral surface of the workpiece W. The grinding wheel T is composed of a plurality of abrasive grains fixed by a bonding material. The abrasive grains can be general abrasive grains formed of ceramic materials such as aluminum oxide and silicon carbide, super abrasive grains such as diamond and CBN, etc.

[0039] The grinding head body 51 is formed in a rectangular shape, for example, and is supported by the X-axis guide surface 13 of the bed 10 so as to be movable in the X-axis direction (horizontal front-back direction). In addition, the grinding head body 51 is fixed to the ball screw nut of the X-axis ball screw mechanism 14a, and is moved in the X-axis direction by the rotation drive of the X-axis motor 14b. In addition, the grinding head body 51 has a cylindrical portion as a shaft housing in the front of the X-axis direction.

[0040] The grinding wheel spindle unit 52 is rotatably supported by the cylindrical portion of the grinding head body 51 via a bearing (not shown). The grinding wheel spindle unit 52 holds the grinding wheel T, and the grinding wheel T rotates along with the rotation of the grinding wheel spindle unit 52. The grinding wheel motor 53 rotationally drives the grinding wheel spindle unit 52. For example, the grinding wheel motor 53 transmits the rotational driving force to the grinding wheel spindle unit 52 via a belt. However, the grinding wheel motor 53 may also be coaxially arranged with the grinding wheel spindle unit 52.

[0041] The grinding wheel cover 54 is non-rotatably provided on the grinding head body 51 and covers a part of the grinding wheel T. The grinding wheel cover 54 opens at least a region on the workpiece W side (the front side in the X-axis direction) to expose the grinding wheel T.

[0042] The detection unit 60 is mounted on the grinding wheel T or the grinding wheel spindle unit 52 as the detection object, and includes a sensor S that outputs an analog detection signal. In the present embodiment, the sensor S is an AE sensor that detects elastic waves generated by the grinding wheel T when the grinding wheel T grinds the workpiece W and outputs an AE signal as an analog detection signal. Hereinafter, the sensor S is referred to as an AE sensor S. The detection unit 60 can wirelessly communicate the analog detection signal output by the AE sensor S.

[0043] The sizing device 70 is provided on the upper surface of the bed 10 and measures the outer diameter of the workpiece W. The sizing device 70 includes, for example, a pair of contacts that can contact the outer peripheral surface of the workpiece W and measures the outer diameter of the contact portion with the workpiece W.

[0044] The control device 80 is a CNC device that performs machining control. That is, the control device 80 drives the Z-axis drive mechanism 12 and the X-axis drive mechanism 14 as the moving device based on the machining program and the measurement results of the sizing device 70 to perform position control of the workbench 20 and the grinding head 50. That is, the control device 80 makes the workpiece W and the grinding wheel T relatively close to and separated by performing position control of the workbench 20 and the grinding head 50. In addition, the control device 80 controls the spindle device 30 and the grinding head 50. That is, the control device 80 performs rotation control of the spindle 32 and the rotation control of the grinding wheel T.

[0045] In addition, the control device 80 can also estimate the surface properties of the workpiece W based on the AE signal detected by the AE sensor S constituting the detection unit 60, and perform machining control based on the estimated surface properties of the workpiece W. For example, the control device 80 can estimate the machining quality of the workpiece W based on the estimated surface properties of the workpiece W, thereby making a pass / fail determination of the workpiece W, or estimating the surface state of the grinding wheel T. The estimation result of the surface state of the grinding wheel T can also be used to determine the timing of correcting the grinding wheel T, or to determine the timing of replacing the grinding wheel T.

[0046] 2. Wear caused by grinding

[0047] Reference Figure 2 The wear caused by grinding is described below. Grinding by the grinding machine 1 is a phenomenon in which the relatively soft workpiece W is minutely cut by the hard abrasive grains constituting the grinding wheel T. It is also known that grinding is a complex phenomenon of abrasive wear and severe wear.

[0048] The AE sensor S constituting the grinding machine 1 detects elastic waves generated by wear during grinding and outputs an AE signal as an analog detection signal. Each wear is represented by the relationship between the frequency of the AE signal and the amplitude of the AE signal.

[0049] like Figure 2 As shown, the frequency of the AE signal is 0.1MHz to 0.3MHz for light wear, 0.3MHz to 1.1MHz for abrasive wear, and 0.9MHz to 1.6MHz for severe wear. As for the amplitude of the AE signal, relatively speaking, light wear and abrasive wear are smaller, while severe wear is larger.

[0050] 3. Structure of the communication device 100

[0051] Reference Figure 3 The structure of the communication device 100 is described. The communication device 100 includes a grinding head 50, a detection unit 60, and a part of the control device 80 (such as a surface property estimation unit 81 described later). Figure 3 , a part of the grinding head 50 and the detection unit 60 are shown. The communication device 100 includes an AE sensor S, and wirelessly communicates an AE signal outputted from the AE sensor S. The communication device 100 estimates the surface property of the workpiece W based on the AE signal, for example.

[0052] As described above, the grinding head 50 includes a grinding wheel T, a grinding head body 51, a grinding wheel shaft unit 52, a grinding wheel motor 53, and a grinding wheel cover 54. The grinding wheel shaft unit 52 includes a grinding wheel shaft 52a and a mounting member 52b. The grinding wheel shaft 52a is formed in an axial shape and is supported by a cylindrical portion of the grinding head body 51 via a bearing so as to be rotatable. A grinding wheel T is embedded in the front end of the grinding wheel shaft 52a. The mounting member 52b is a member for clamping and holding the grinding wheel T in the axial direction at the front end of the grinding wheel shaft 52a. Therefore, the grinding wheel T, the grinding wheel shaft 52a, and the mounting member 52b rotate integrally.

[0053] The detection unit 60 includes a first unit 61 and a second unit 62. The first unit 61 is mounted on the grinding wheel spindle unit 52 or the grinding wheel T as the detection object. The grinding wheel spindle unit 52 and the grinding wheel T are rotating bodies that rotate integrally with the rotation center line Ct as the center. Therefore, the first unit 61 rotates with the grinding wheel spindle unit 52 and the grinding wheel T with the rotation center line Ct as the center. The second unit 62 is mounted on the grinding wheel cover 54 or a component that is integral with the grinding wheel cover 54. The second unit 62 is mounted on the grinding head main body 51 or the grinding wheel cover 54, for example. That is, the first unit 61 rotates relative to the second unit 62 with the rotation center line Ct as the center.

[0054] The first unit 61 includes a first unit case 101 , an AE sensor S, a power supply unit 102 , a modulated laser generating device 103 , mounting screws 104 , and a power receiving coil 105 .

[0055] The first unit housing 101 is formed into a bottomed cylindrical shape. The bottom outer surface of the first unit housing 101 is mounted on the axial end surface of the grinding wheel spindle unit 52 in such a manner that the first unit housing 101 and the grinding wheel spindle unit 52 are coaxial. Specifically, the first unit housing 101 is mounted on the axial end surface of the mounting member 52b, that is, the opening side of the first unit housing 101 is located on the opposite side of the grinding wheel spindle unit 52.

[0056] The cylindrical interior of the first unit housing 101 contains an AE sensor S, a power supply unit 102, a modulated laser generating device 103, and a mounting screw 104. As described above, the AE sensor S detects elastic waves generated on the grinding wheel T by grinding the workpiece W with the grinding wheel T and outputs an AE signal as an analog detection signal. The AE sensor S detects elastic waves of light wear, abrasive wear, and severe wear and outputs an AE signal SA1 as an analog detection signal. The AE sensor S is installed in a central recess located on the rotation center line Ct in the bottom surface of the first unit housing 101.

[0057] The power supply unit 102 includes a battery and a power receiving circuit, and is provided on the bottom surface side of the first unit case 101. The power supply unit 102 supplies driving power to the AE sensor S and the modulated laser generating device 103.

[0058] The modulated laser generating device 103 is arranged on the opening side of the first unit housing 101 relative to the power supply unit 102, and is stacked on the power supply unit 102. The modulated laser generating device 103 generates the modulated laser SL by performing a modulation process on the laser fundamental wave based on the AE signal SA1 output by the AE sensor S. The modulated laser generating device 103 generates the modulated laser SL toward the opening side of the first unit housing 101 along the rotation center line Ct.

[0059] The modulated laser light SL may be laser light obtained by performing amplitude modulation processing on the laser fundamental wave, or may be laser light obtained by performing frequency modulation processing on the laser fundamental wave.

[0060] The modulated laser generating device 103 is configured as a semiconductor laser, for example. The modulated laser generating device 103 may adopt a structure that generates a vertical resonator type surface emitting laser, or may adopt a structure that generates an end-emitting laser. The modulated laser generating device 103 may, for example, use a device having a laser bandwidth of 4 GHz and an emission wavelength of approximately 850 nm. By adopting this structure, the modulated laser generating device 103 can generate a modulated laser containing components of abrasive wear and severe wear. However, the modulated laser generating device 103 is not limited to this structure. For example, a device having an emission wavelength of 400 nm to 800 nm may also be used.

[0061] The mounting screw 104 is screwed into the inner circumferential surface of the first unit housing 101 to hold the power supply unit 102 and the modulated laser generating device 103 in the axial direction. A through hole is formed in the center of the mounting screw 104 along the rotation center line Ct. The through hole is formed to a size through which the modulated laser SL can pass.

[0062] The power receiving coil 105 is arranged at the open end of the first unit housing 101. The power receiving coil 105 is a coil for contactless power supply and is connected to the power receiving circuit of the power supply unit 102. The power obtained through the power receiving coil 105 is stored in the battery of the power supply unit 102. In addition, a through hole is formed in the center of the power receiving coil 105 along the rotation center line Ct. The through hole is formed to a size that allows the modulated laser light SL to pass through.

[0063] Here, the power supply unit 102 and the power receiving coil 105 are provided integrally with the modulated laser generating device 103, and constitute a non-contact power receiving unit configured to supply power to the AE sensor S and the modulated laser generating device 103. The non-contact power receiving unit is not limited to a structure having the power receiving coil 105, and other structures can be adopted as long as non-contact power reception is possible.

[0064] 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 .

[0065] The unit cover 111 is attached to the grinding head body 51 or the grinding wheel cover 54. Therefore, the unit cover 111 is set to be non-rotatable. In this embodiment, the unit cover 111 is attached to the grinding wheel cover 54. The unit cover 111 accommodates other components 112, 113, 114, and 115 constituting the second unit 62.

[0066] The second unit casing 112 is attached to the unit cover 111 and is disposed to face the first unit 61 in the direction of the rotation center line Ct. The second unit casing 112 is formed in a bottomed cylindrical shape and is disposed with its opening facing the first unit 61 side.

[0067] The power supply unit 113 includes a power supply circuit and is provided on the bottom surface side of the cylinder interior of the second unit casing 112 .

[0068] The laser receiving device 114 is housed inside the cylinder of the second unit housing 112. Therefore, the laser receiving device 114 is set to be non-rotatable and is arranged opposite to 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. In particular, the laser receiving device 114 receives the modulated laser generated along the rotation center line Ct. Moreover, the laser receiving device 114 generates a demodulated analog signal SA2 by performing a demodulation process on the received modulated laser SL. Hereinafter, the demodulated analog signal SA2 is referred to as a demodulated AE signal.

[0069] The laser receiving device 114 uses, for example, a Si high-speed photodiode. The responsiveness of the laser receiving device 114 is set to, for example, 2 GHz. By adopting this structure, the laser receiving device 114 can generate a demodulated AE signal SA2 containing components of abrasive wear and severe wear. However, the laser receiving device 114 is not limited to this structure.

[0070] The modulated laser light SL is generated by the modulated laser light generating device 103 of the rotating first unit 61 and received by the laser receiving device 114 of the second unit 62 which is set not to rotate. Here, the modulated laser light SL is generated along the rotation center line Ct, so the position of the modulated laser light SL does not deviate greatly. Therefore, the laser receiving device 114 can reliably receive the modulated laser light generated by the rotating modulated laser light generating device 103.

[0071] The power supply coil 115 is arranged at the open end of the second unit housing 112. The power supply coil 115 is a coil for contactless power supply and is connected to the power supply circuit of the power supply unit 113. The power supply coil 115 is opposed to the power receiving coil 105 at a distance. In addition, a through hole is formed in the center of the power supply coil 115 along the rotation center line Ct. The through hole is formed to a size that allows the modulated laser SL to pass through.

[0072] Here, the power supply unit 113 and the power supply coil 115 are provided integrally with the laser receiving device 114, and constitute a non-contact power supply unit, which is configured to be able to perform non-contact power supply with respect to the power supply unit 102 and the power receiving coil 105 as the non-contact power receiving unit constituting the first unit 61. The non-contact power receiving unit is not limited to a structure having the power supply coil 115, and other structures can be adopted as long as non-contact power supply can be performed.

[0073] 4. Functional Structure of Communication Device 100

[0074] Reference Figure 4 The functional structure of the communication device 100 is described. Figure 4 As shown, the AE sensor S outputs an AE signal SA1 which is an analog detection signal. The AE signal SA1 is a signal based on elastic waves generated by light wear, abrasive wear, and heavy wear.

[0075] The AE signal SA1 is converted into a modulated laser light SL in the modulated laser light generating device 103. Figure 4 In the figure, the modulated laser light SL is a laser light obtained by performing amplitude modulation processing on the laser fundamental wave based on the AE signal SA1. That is, the frequency of the modulated laser light SL is the same as the laser fundamental wave, and the amplitude of the modulated laser light SL is a magnitude corresponding to the AE signal SA1.

[0076] In particular, the modulation band of the modulated laser SL includes at least a frequency band above 1.0 MHz. More preferably, the modulation band of the modulated laser SL may include at least any frequency band in the range of 1.0 MHz to 2.0 MHz. Therefore, the modulated laser SL can reliably transmit the components of abrasive wear and severe wear. In the present embodiment, the modulation band of the modulated laser SL includes each of the frequency band above 1.0 MHz and any frequency band in the range of 50 kHz to 500 kHz. Therefore, the modulated laser SL can more reliably transmit the components of abrasive wear and severe wear. For example, the modulation band of the modulated laser SL is set to 300 kHz to 1.8 MHz, etc.

[0077] The modulated laser light SL is generated by the modulated laser light generating device 103 of the rotating first unit 61 and received by the laser receiving device 114 of the second unit 62 which is set not to rotate. By using the modulated laser light SL, wireless communication can be performed between the modulated laser light generating device 103 and the laser receiving device 114. Figure 3 As described above, the modulated laser light SL is generated along the rotation center line Ct. Therefore, even if the modulated laser light generator 103 and the laser receiving device 114 rotate relatively, the position of the generated modulated laser light SL does not shift significantly, and the laser receiving device 114 can reliably receive the modulated laser light.

[0078] The control device 80 includes a surface property estimation unit 81. The surface property estimation unit 81 obtains the demodulated AE signal SA2, and estimates the surface property of the workpiece W based on the demodulated AE signal SA2. The AE signal SA1 includes components of light wear, abrasive wear, and severe wear, and the modulated laser SL becomes a laser including components of abrasive wear and severe wear. Moreover, the demodulated AE signal SA2 becomes a signal that retains components of abrasive wear and severe wear. Therefore, by using the demodulated AE signal SA2 for analysis, the complex phenomenon of abrasive wear and severe wear can be grasped, and the surface property of the workpiece W can be estimated.

[0079] Furthermore, the control device 80 can use the estimation result of the surface property estimation unit 81 to perform quality discrimination of the workpiece W. In addition, although the control device 80 is provided with the surface property estimation unit 81 as an example, a processing unit different from the control device 80 is provided with the surface property estimation unit 81 .

[0080] 5. Relationship between AE signal SA1 and demodulated AE signal SA2

[0081] Reference Figure 5 The relationship between the AE signal SA1 and the demodulated AE signal SA2 is described. As described above, the AE signal SA1 is converted into the modulated laser light SL, and the demodulated AE signal SA2 is generated using the modulated laser light SL. That is, the AE signal SA1 and the demodulated AE signal SA2 are signals converted via the modulated laser light SL.

[0082] In addition, the ratio (SA1 / SA2) of the AE signal SA1 to the demodulated AE signal SA2 varies depending on the modulation frequency of the modulated laser. Figure 5 Here, the modulation frequency is equivalent to the frequency of the AE signal SA1.

[0083] exist Figure 5 In the example, the vertical axis (unit [dB]) represents the value of the common logarithm of the ratio of the AE signal SA1 to the demodulated AE signal SA2. That is, a vertical axis of 0 corresponds to a ratio of the AE signal SA1 to the demodulated AE signal SA2 of 1. Figure 5 In the modulation frequency range of 100kHz to 1.0MHz, the ratio of the AE signal SA1 to the demodulated AE signal SA2 is 1. However, depending on the configuration of the communication device 100, even if the ratio of the AE signal SA1 to the demodulated AE signal SA2 is in a range that is substantially constant, the ratio may be different from 1.

[0084] Moreover, if Figure 5As shown in FIG. 1 , in the modulation frequency range Δf of 50kHz to 2.0MHz, the ratio of the AE signal SA1 to the demodulated AE signal SA2 is within the prescribed allowable range. The allowable range here refers to the prescribed range in which the difference is taken into account. That is, in the modulation frequency range Δf of 50kHz to 2.0MHz, the ratio of the AE signal SA1 before the modulation process to the demodulated AE signal SA2 is approximately constant (approximately 1, Figure 5 That is, the modulation frequency Δf in the range of 50kHz to 2.0MHz has sufficient linearity. Figure 5 As shown, in the modulation frequency range of 80 kHz to 1.5 MHz, the ratio of the AE signal SA1 before modulation processing and the demodulated AE signal SA2 is included in an extremely small range and has extremely high linearity.

[0085] Assuming that the ratio of the AE signal SA1 to the demodulated AE signal SA2 is approximately 1 (0 dB), the AE signal SA1 and the demodulated AE signal SA2 are approximately identical in the range Δf of the modulation frequency from 50 kHz to 2.0 MHz. However, even if the ratio is not 1, if the ratio is in the range Δf of the modulation frequency within the prescribed allowable range, the AE signal SA1 and the demodulated AE signal SA2 have a constant relationship, so the AE signal SA1 can be inferred from the demodulated AE signal SA2.

[0086] And, in Figure 2 The modulation frequency band Δf of 50kHz to 2.0MHz, where the ratio of the AE signal SA1 before modulation to the demodulated AE signal SA2 is substantially constant, includes the frequency bands of abrasive wear and severe wear. Therefore, it is known that the modulated laser SL can be used to transmit the components of abrasive wear and severe wear.

[0087] 6. Effects of implementation methods

[0088] According to the communication device 100 of this embodiment, the modulated laser generating device 103 constituting the communication device 100 generates the modulated laser SL. Therefore, the transmission of the modulated laser SL is less susceptible to the influence of noise than the transmission of radio waves. As a result, even if the analog detection signal (AE signal) SA1 of the communication object is a weak signal in the high frequency band, it can be transmitted without being susceptible to the influence of noise.

[0089] Furthermore, the modulated laser light SL generated as the transmission signal is generated by performing a modulation process on the laser fundamental wave based on the AE signal SA1 output by the AE sensor S. That is, the modulated laser light SL is a laser light to which an analog modulation process is performed on the laser fundamental wave. Therefore, the communication device 100 can adopt a simple structure and can be realized at a low cost. In addition, since it is not necessary to perform A / D conversion on the analog detection signal, that is, the AE signal SA1, an A / D converter is not required. Therefore, in this regard, it can also be set as a low-cost communication device 100.

[0090] Therefore, according to the communication device 100 of the present embodiment, even if the AE signal SA1 which is the analog detection signal of the communication object is a weak signal in the high frequency band, it is less susceptible to the influence of noise and can perform communication at low cost.

[0091] The laser receiving device 114 constituting the communication device 100 receives the modulated laser light SL generated by the modulated laser generating device 103 and generates a demodulated analog signal (demodulated AE signal) SA2 by demodulating the modulated laser light SL. Thus, the communication device 100 can transmit and receive the AE signal SA1 via the modulated laser light SL.

[0092] The modulated laser generating device 103 performs amplitude modulation processing as the modulation processing. By applying the amplitude modulation processing, it is possible to easily and reliably perform the modulation processing based on the AE signal SA1 on the laser fundamental wave.

[0093] In addition, the AE sensor S is mounted on the grinding wheel T or the grinding wheel spindle unit 52, which is a detection object as a rotating body. Moreover, the modulated laser generating device 103 is arranged at the axial end of the grinding wheel T and the grinding wheel spindle unit 52, and generates the modulated laser SL along the rotation center line Ct. Even if the modulated laser generating device 103 is mounted on the rotating body, the modulated laser SL is generated along the rotation center line Ct, and the position deviation of the modulated laser SL does not occur. Therefore, the modulated laser SL can be sent at a stable position.

[0094] Furthermore, the laser receiving device 114 is set to be non-rotatable and is arranged opposite to 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.

[0095] The AE sensor S is attached to the grinding wheel T or the grinding wheel spindle unit 52, detects elastic waves generated in the grinding wheel T, and outputs an AE signal as an analog detection signal. As a result, the phenomenon of grinding can be reliably analyzed.

[0096] In addition, the AE sensor S is mounted on the grinding wheel T or the grinding wheel spindle unit 52 to detect the elastic wave generated on the grinding wheel T and output the AE signal, and the laser receiving device 114 is mounted on the grinding wheel cover 54. By setting such a mounting relationship, the AE sensor S, the modulated laser generating device 103 and the laser receiving device 114 can be installed at a desired position.

[0097] In this embodiment, the AE sensor S detects elastic waves caused by abrasive wear or severe wear during grinding and outputs an AE signal SA1. In addition, the laser receiving device 114 generates a demodulated AE signal SA2 containing abrasive wear or severe wear components. Therefore, the phenomenon of grinding can be reliably grasped.

[0098] In addition, the modulation band of the modulated laser SL may include at least a frequency band of 1.0 MHz or more. More preferably, the modulation band of the modulated laser SL may include at least any frequency band in the range of 1.0 MHz to 2.0 MHz. Even with such a high-frequency band, since it is not easily affected by noise, the communication of the AE signal SA1 in the high-frequency band can be reliably performed. Moreover, the modulation band in the modulated laser SL may include a frequency band of 1.0 MHz or more and any frequency band in the range of 50 kHz to 500 kHz. In this way, in addition to the high-frequency band, a low-frequency band is also included, so that the phenomenon of grinding processing can be reliably grasped.

[0099] In particular, the modulation frequency band in the modulated laser SL can be set to a frequency band where the ratio (SA1 / SA2) of the AE signal SA1 before modulation processing and the demodulated AE signal SA2 after demodulation processing is substantially constant. Thus, the state of the AE signal SA1 can be accurately grasped using the demodulated AE signal SA2.

[0100] Furthermore, the surface property estimation unit 81 estimates the surface property of the workpiece W ground by the grinding wheel T based on the demodulated AE signal SA2. Abrasive wear and severe wear can be understood based on the demodulated AE signal SA2, so the surface property of the workpiece W estimated using the demodulated AE signal SA2 becomes highly accurate.

[0101] In addition, the detection unit 60 includes a first unit 61 that rotates and a second unit 62 that cannot rotate. The first unit 61 is provided with an AE sensor S and a modulated laser generator 103, and is also provided with a non-contact power receiving unit (102, 105), which is integrally provided with the modulated laser generator 103 and is configured to supply power to the AE sensor S. On the other hand, the second unit 62 is provided with a laser receiving device 114, and is also provided with a non-contact power supply unit (113, 115), which is integrally provided with the laser receiving device 114 and is configured to be able to supply power to the non-contact power receiving unit (102, 105) in a non-contact manner. Therefore, even if the AE sensor S and the modulated laser generator 103 are provided in the rotating first unit 61, power can be supplied to them.

[0102] (Implementation Method 2)

[0103] Main reference Figure 6 And add reference Figure 5 The communication device 200 of this embodiment is described. The communication device 200 of this embodiment is different from the communication device 100 of Embodiment 1 in the structure of the laser receiving device 214. The laser receiving device 214 is described below. In addition, the same components as those used in the previous embodiment in the reference numerals used in the embodiments after Embodiment 2 represent the same structural members as those in the previous embodiment unless otherwise specified.

[0104] The laser receiving device 214 receives the modulated laser light SL generated by the modulated laser generating device 103 and generates a demodulated AE signal SA2. Figure 5 , the ratio of the AE signal SA1 to the demodulated AE signal SA2 is approximately a constant value of 1 (0 dB) when the modulation frequency is 50 kHz to 2.0 MHz. When the ratio is not 1 (0 dB), the AE signal SA1 and the demodulated AE signal SA2 have a certain relationship, but they are not consistent.

[0105] Therefore, in this embodiment, even if Figure 5 Even when the ratio in is not 1, the laser receiving device 214 corrects the demodulated AE signal SA2 so that the demodulated AE signal SA2 coincides with the AE signal SA1.

[0106] In this case, if Figure 6As shown, 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 light SL. The demodulation processing unit 202 performs a demodulation process on the received modulated laser light SL and generates a pre-correction demodulated AE signal. The correction unit 203 generates a post-correction demodulated AE signal SA2 by correcting the demodulated pre-correction demodulated AE signal. Even if the pre-correction demodulated AE signal is inconsistent with the AE signal SA1, the post-correction demodulated AE signal SA2 can be made consistent with the AE signal SA1.

[0107] According to the present embodiment, since the corrected demodulated AE signal SA2 is consistent with the AE signal SA1, high-precision processing can be performed in the processing using the corrected demodulated AE signal SA2. For example, when the surface property estimation unit 81 estimates the surface property of the workpiece W, the surface property of the workpiece W can be estimated with high precision.

[0108] (Implementation method 3)

[0109] Reference Figure 7 Communication device 300 of this embodiment will be described. Communication device 300 of this embodiment is different from communication device 100 of Embodiment 1 in the configurations of modulated laser generating device 301 and laser receiving device 302. Modulated laser generating device 301 and laser receiving device 302 will be described below.

[0110] The modulated laser generating device 301 generates the modulated laser SL by frequency modulating the laser fundamental wave based on the AE signal SA1. That is, the amplitude of the modulated laser SL is constant relative to the laser fundamental wave, but the frequency is different. Furthermore, the laser receiving device 302 receives the modulated laser SL and generates the demodulated AE signal SA2 by performing a demodulation process. The demodulation process in the laser receiving device 302 of this embodiment is a frequency demodulation process.

[0111] This embodiment also achieves the same effects as those of Embodiment 1. However, in the generation of modulated laser light, amplitude modulation is easier than frequency modulation. Therefore, the amplitude modulation of Embodiment 1 can easily generate modulated laser light.

[0112] (other)

[0113] In the above embodiment, the communication device 100, 200, 300 is applied to the grinding machine 1. However, the communication device 100, 200, 300 can be applied to other than the grinding machine 1. For example, it can be applied to machine tools other than the grinding machine 1 or other industrial machines.

[0114] In the above embodiment, the AE sensor S is used as an example of a sensor that outputs an analog detection signal. However, even if the sensor is other than the AE sensor S, it can be applied as long as it is a sensor that outputs an analog detection signal. In particular, it is useful in the case of wirelessly communicating an analog detection signal in a high frequency band of 1.0 MHz or more.

Claims

1. A communication device (100, 200, 300), wherein: have: A sensor (S) mounted on a detection object (52, T) and outputting an analog detection signal (SA1); and A modulated laser generating device (103, 301) generates modulated laser light (SL) by performing a modulation process on a laser fundamental wave based on the analog detection signal.

2. The communication device according to claim 1, wherein: Also available: A laser receiving device (114, 214, 302) receives the modulated laser light generated by the modulated laser light generating device and generates a demodulated analog signal (SA2) by performing demodulation processing on the modulated laser light.

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. The communication device according to claim 1 or 2, wherein: The detection object is a rotating body. The modulated laser generating device is disposed at an axial end of the rotating body and generates the modulated laser along a rotation center line (Ct) of the rotating body.

5. The communication device according to claim 2, wherein: The detection object is a rotating body. The modulated laser generating device is disposed at the axial end of the rotating body and generates the modulated laser along the rotation center line (Ct) of the rotating body. The laser receiving device is non-rotatably arranged to face the modulated laser generating device in the 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 according to claim 1, wherein: Also available: A grinding wheel (T) for grinding a workpiece (W), and a grinding wheel spindle unit (52) for holding the grinding wheel, The sensor is an AE sensor that is attached to the grinding wheel or the grinding wheel spindle unit, detects elastic waves generated in the grinding wheel, and outputs an AE signal as the analog detection signal.

7. The communication device according to claim 2, wherein: Also available: A grinding wheel (T) for grinding a workpiece (W); a grinding wheel spindle unit (52) for holding the grinding wheel; and A grinding wheel cover (54) is arranged to be non-rotatable and covers a portion of the grinding wheel. The sensor is an AE sensor which is arranged on the grinding wheel or the grinding wheel spindle unit, detects elastic waves generated on the grinding wheel and outputs an AE signal as the analog detection signal. The laser receiving device is installed on the grinding wheel cover or a component integrated 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 during grinding and outputs the AE signal as the analog detection signal.

9. The communication device according to claim 7, wherein: The AE sensor detects the elastic wave caused by abrasive wear or severe wear during grinding and outputs the AE signal as the analog detection signal. The laser receiving device generates the demodulated analog signal including the component of the abrasive wear or the severe wear.

10. The communication device according to claim 1 or 2, wherein: The modulation frequency band of the modulated laser light at least includes a frequency band of 1.0 MHz or more.

11. The communication device according to claim 10, wherein: The modulation frequency band of the modulated laser light includes a frequency band of 1.0 MHz or more and any frequency band within a range of 50 kHz to 500 kHz.

12. The communication device according to claim 2, wherein: The modulation band of the modulated laser light is a band in which the ratio of the analog detection signal before modulation processing and the demodulated analog signal after demodulation processing falls within a predetermined allowable range.

13. The communication device according to claim 2, wherein: The laser receiving device corrects the demodulated analog signal in such a manner that the demodulated analog signal is consistent with the analog detection signal.

14. The communication device according to claim 2, wherein: The object to be detected is a grinding wheel (T) for grinding a workpiece (W). The sensor is an AE sensor that detects elastic waves generated on the grinding wheel and outputs an AE signal as the analog detection signal. The communication device further includes a surface property estimation unit (81) for estimating the surface property of the workpiece ground by the grinding wheel based on the demodulated analog signal.

15. The communication device according to claim 2, wherein: Also available: a non-contact power receiving unit (102, 105) which is integrally provided with the modulated laser generating device and configured to supply power to the sensor; and A non-contact power supply unit (113, 115) is provided integrally with the laser receiving device and is configured to be able to perform non-contact power supply to the non-contact power receiving unit.

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