Sensor unit and sensor system

Abstract

A sensor unit and a sensor system capable of constructing a high-sensitivity force sensing system at low cost with few constraints related to the size of a workpiece are provided. The sensor unit of an embodiment includes a linear piezoelectric sensor and a measurement section having a guide groove that holds a portion of the piezoelectric sensor and an abutting surface that abuts against a measurement target at a predetermined pressure.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to a sensor unit and a sensor system. BACKGROUND

[0002] In the past, a force sensing system has been proposed to be used in state diagnosis related to a machining process.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Laid-Open (JP A) No. 2007-000251

[0006] Patent Document 2: Japanese Patent Application Laid-Open (JP A) No. 2007-185409

[0007] Patent Document 3: Japanese Patent Application Laid-Open (JP A) No. 2006-215859

[0008] Patent Document 4: Japanese Patent No. 3658166 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] However, in the related art, a ceramic piezoelectric element is used as a force sensor in a field requiring high sensitivity and a high dynamic range, but there are many constraints related to the size of a workpiece, a unit needs to be designed specifically corresponding to a machining load level, the cost is increased, and this hinders the spread.

[0011] The present application has been made in view of the above problems, and it is an object to provide a sensor unit and a sensor system which can construct a force sensing system with high sensitivity at low cost with few constraints related to the size of a workpiece.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] The sensor unit of the embodiment includes a linear piezoelectric sensor, and a measurement section having a guide groove that holds a portion of the piezoelectric sensor and an abutting surface that abuts against a measurement object with a predetermined pressure. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic configuration block diagram of the measurement system of the embodiment.

[0015] Figure 2 is a front view of the linear sensor.

[0016] Figure 3 is an A-A end surface cross-sectional view of the linear sensor of Figure 2

[0017] ​Figure 4 is Figure 2 a B-B end view of the linear sensor.

[0018] Figure 5 is a processing flowchart of the measurement system.

[0019] Figure 6 is a diagram explaining the relationship between the number of guide grooves in the linear sensor and the output signal.

[0020] Figure 7 is an explanatory diagram (one) in the case where measurement is performed under the same conditions as the machining conditions at the time of calibration.

[0021] Figure 8 is an explanatory diagram (two) in the case where measurement is performed under the same conditions as the machining conditions at the time of calibration.

[0022] Figure 9 is an explanatory diagram (one) of the measurement results in the case where the machining conditions at the time of calibration are changed.

[0023] Figure 10 is an explanatory diagram (two) of the measurement results in the case where the machining conditions at the time of calibration are changed.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 10 measurement system

[0026] 11 first linear sensor

[0027] 12 second linear sensor

[0028] 13 third linear sensor

[0029] 14 first linear sensor amplifier

[0030] 15 second linear sensor amplifier

[0031] 16 third linear sensor amplifier

[0032] 17 table measurement unit

[0033] 18 unit amplifier

[0034] 19 signal collection / analysis computer

[0035] 20 machining device

[0036] 20A tool holder

[0037] 20B tool spindle

[0038] 20C X table

[0039] 20D Y table

[0040] 20E Z table

[0041] 21 CNC device

[0042] 31 piezoelectric sensor

[0043] 31A redundancy portion

[0044] 32, 32A to 32D guide groove

[0045] 33 abutting portion (measurement portion)

[0046] 33A abutting surface

[0047] 34 cushion member (cushion holding portion)

[0048] 35 protection tube

[0049] 36 connector

[0050] 41 covering member

[0051] 42 anti-adhesion member

[0052] 43 connector

[0053] 51 pressurizing portion (measurement portion)

[0054] Cx1, Cx2, Cx3, Cx4, Cy1, Cy2, Cy3, Cy4, Cz1, Cz2, Cz3, Cz4 calibration coefficient

[0055] Fx sensor unit data

[0056] OBJ measurement object

[0057] TL processing tool DETAILED DESCRIPTION

[0058] Next, an embodiment will be described with reference to the drawings.

[0059] Figure 1 is a schematic configuration block diagram of a measurement system of the embodiment.

[0060] The measurement system 10 is constructed as a cutting force measurement system that measures a cutting force at the time of cutting of a processing object as a force sense.

[0061] The measurement system 10 is provided with a first wire sensor 11 that detects a cutting force in the X-axis direction of a measurement object OBJ that is a processing target, a second wire sensor 12 that detects a cutting force in the Y-axis direction of the measurement object OBJ, a third wire sensor 13 that detects a cutting force in the Z-axis direction of the measurement object OBJ, a first wire sensor amplifier 14 that amplifies and outputs an output signal of the first wire sensor 11, a second wire sensor amplifier 15 that amplifies and outputs an output signal of the second wire sensor 12, a third wire sensor amplifier 16 that amplifies and outputs an output signal of the third wire sensor 13, a table measurement unit 17 that is used when calibration of the first wire sensor 11 to the third wire sensor 13 is performed, a unit amplifier 18 that amplifies and outputs an output signal (3 channels) of the table measurement unit 17, a signal collection / analysis computer 19 that performs calibration of the output signals of the first wire sensor amplifier 14 to the third wire sensor amplifier 16 based on the output signals of the first wire sensor amplifier 14 to the third wire sensor amplifier 16 and the unit amplifier 18, and a CNC (Computerized Numerical Control) device 21 that performs numerical control of a processing device 20 (20A, 20B, 20C, 20D, 20E) based on a result of analysis by the signal collection / analysis computer 19 and based on a prescribed NC program.

[0062] In the above structure, the processing device 20 is provided with a tool holder 20A that holds a processing tool (for example, a cutting tool) TL such as a drill bit / end mill, a tool spindle 20B that holds the tool holder 20A and rotationally drives it, an X table 20C that drives the tool spindle 20B in the X direction, a Y table 20D that drives the tool spindle 20B in the Y direction, and a Z table 20E that drives the measurement object OBJ that is a processing target in the Z direction.

[0063] In addition, the first wire sensor 11, the second wire sensor 12, and the third wire sensor 13 function as sensor units.

[0064] Figure 2 is a front view of a wire sensor.

[0065] The first wire sensor 11 to the third wire sensor 13 are the same structure, so the first wire sensor 11 is described in Figure 2 .

[0066] The first linear sensor 11 includes: a linear piezoelectric sensor 31; an abutment portion 33 having guide grooves 32 (32A, 32B, 32C, 32D) for holding a portion of the piezoelectric sensor 31 other than the redundant portion 31A of the piezoelectric sensor 31, and having an abutment surface 33A that abuts against the workpiece OBJ, which is the object to be measured, at a predetermined pressure; a buffer member (e.g., anti-vibration rubber) 34 provided along the side edge of the abutment portion 33 where the redundant portion 31A of the piezoelectric sensor 31 is provided; a protective tube 35 provided at the front end side of the piezoelectric sensor 31; and a connector 36 electrically connected to the piezoelectric sensor 31 at the base end side of the piezoelectric sensor 31, which serves as the output end.

[0067] Moreover, at the contact section 33 Figure 2 In the middle, a pressure part 51 is provided on the back side, which applies pressure during measurement to press the contact part 33 against the object being measured OBJ to maintain the contact state (see reference). Figure 4 ).

[0068] Here, the contact part 33 and the pressurizing part 51 function as measuring parts.

[0069] In the above structure, the lengths of guide grooves 32A, 32B, 32C, and 32D are set to be the same.

[0070] This is to ensure that the contribution (the generated voltage of the piezoelectric sensor 31 in each guide groove 32A, 32B, 32C, 32D) is the same when increasing the generated voltage helps to improve sensitivity.

[0071] exist Figure 2 The example shows a configuration of four guide slots 32A to 32D, but the number of guide slots 32 can be any number, including more than one. In this case, with m guide slots 32 (m being an integer greater than or equal to 2), the output voltage of the line sensor can be set to approximately m times the value of a single guide slot, thus improving sensitivity. Details will be provided later.

[0072] Figure 3 yes Figure 2 A-A end section view of the line sensor.

[0073] like Figure 3 As shown, on the base end side of the piezoelectric sensor 31 of the first line sensor 11, the extension of the piezoelectric sensor 31 between it and the connector 36 is covered by the covering member 41, thereby suppressing the vibration of the extension of the piezoelectric sensor 31 and preventing the adhesion of machining waste (cutting chips, etc.) accompanying the processing.

[0074] In addition, connector 36 is preferably fixed in a location that is not easily affected by vibrations during processing.

[0075] Further, a signal transmission cable between the connector 36 and a connector 43 connected to the first line sensor amplifier 14 is covered by an anti-attachment member 42 that prevents attachment of machining waste (cutting chips, etc.) that accompanies machining.

[0076] Here, the anti-attachment member 42 is, for example, a bellows or the like.

[0077] Further, in the piezoelectric sensor 31, a portion that extends from the guide groove 32, particularly the redundant portion 31A, is held by the buffer member 34 as shown in Figs. 9 and 10, so that measurement by the portion of the piezoelectric sensor 31 that is positioned within the guide groove 32 (32A to 32D) is not hindered. Figure 2 Figure 3 Further, in the piezoelectric sensor 31, a portion that extends from the guide groove 32, particularly the redundant portion 31A, is held by the buffer member 34 as shown in Figs. 9 and 10, so that measurement by the portion of the piezoelectric sensor 31 that is positioned within the guide groove 32 (32A to 32D) is not hindered.

[0078] In this case, the buffer member 34 functions as a buffer holding portion that holds the other portion of the piezoelectric sensor 31 (particularly the redundant portion 31A) other than the portion that is housed within the guide grooves 32A to 32D of the piezoelectric sensor 31 in a buffered state.

[0079] Further, the buffer member 34 is provided in a rectangular cross-sectional shape, but can be configured so that the upper surface of the buffer member 34 in Fig. 8 is formed as an inclined surface along a direction that is separated from the abutting surface 33A of the abutting portion 33, so that the buffer member 34 is separated from the measurement target object OBJ. In this case, it is preferable to fix the redundant portion 31A to the buffer member 34 by a fixing member such as a tape or an adhesive. Figure 3

[0080] is a B-B end surface cross-sectional view of the line sensor of Figure 4 Figure 2

[0081] The depth (length in the up-and-down direction in Fig. 8) of the guide grooves 32A, 32B, 32C, 32D is set to a depth that protrudes a portion of the housed piezoelectric sensor 31 in the radial direction of the piezoelectric sensor 31. Figure 4 Specifically, in the case where the diameter of the linear piezoelectric sensor 31 is set to 0.5 mm, it is set to 0.45 mm, for example.

[0082] Further, the width (length in the left-and-right direction in Fig. 8) of the guide grooves 32A, 32B, 32C, 32D is set to a width that achieves a sufficient separation distance, so that even in the case where the abutting surface 33A of the abutting portion 33 is in abutment with the measurement target object OBJ and the piezoelectric sensor 31 is deformed, it is separated from the side walls of the guide grooves 32A, 32B, 32C, 32D (length in the left-and-right direction in Fig. 8).

[0083] Figure 4 Figure 4 ​​​​​The guide grooves 32A, 32B, 32C, 32D are formed so as not to apply pressure to the piezoelectric sensor 31 by abutting against the wall surface (a wall surface in the left-right direction) of the guide groove 32A, 32B, 32C, 32D. That is, the width of the guide grooves 32A, 32B, 32C, 32D is set to a width that does not hinder the deformation of the piezoelectric sensor 31 in the guide grooves 32A, 32B, 32C, 32D accompanying the application of pressure.

[0084] Specifically, in a case where the diameter of the linear piezoelectric sensor 31 is set to 0.5 mm, for example, it is set to 1.0 mm.

[0085] Next, the operation of the measurement system 10 of the embodiment will be described.

[0086] Figure 5 is a processing flowchart of the measurement system.

[0087] First, in a case where the measurement system is operated, sensor installation is performed in which the first to third linear sensors 11 to 13 that constitute the sensor unit and the table measurement unit 17 for calibrating the first to third linear sensors 11 to 13 are installed in a prescribed orientation to the measurement object OBJ (step S11).

[0088] More specifically, in the table measurement unit 17 placed on the Z table 20E, the measurement object OBJ on which the first to third linear sensors 11 to 13 are installed is placed on a surface opposite to the tool holder 20A that holds the machining tool TL.

[0089] Next, the signal collection conditions of the signal collection / analysis computer 19, such as the sampling timing, the collection voltage range, and the like, are set (step S12).

[0090] In parallel with this, the placement of the workpiece (measurement object OBJ) and the machining tool TL on the machining device 20 is performed (step S13), and the setting of the machining data for performing numerical control of the machining device 20 is performed (step S14).

[0091] Next, the operator starts the drive of the machining tool TL of the machining device 20 (step S15), and the machining of the measurement object OBJ and the data collection by the signal collection / analysis computer 19 are started (step S16).

[0092] Thus, in parallel with the machining of the machining device 20, the signal collection / analysis computer 19 collects the output signal of the table measurement unit 17 as the sensor unit data Fx, Fy, Fz at each prescribed sampling timing based on the output of the unit amplifier 18 (step S17).

[0093] In addition, in parallel with the collection of the sensor unit data Fx, Fy, Fz, the signal collection / analysis computer 19 collects the output signals of the first to third line sensors 11 to 13 based on the outputs of the first to third line sensor amplifiers 14 to 16 in a sampling timing that synchronizes the line sensor data wireX, wireY, wireZ with the prescribed sampling timing of the sensor unit data Fx, Fy, Fz (step S18).

[0094] Then, the signal collection / analysis computer 19 stores the collected sensor unit data Fx, Fy, Fz and line sensor data wireX, wireY, wireZ in correspondence with the sampling timing.

[0095] Next, the signal collection / analysis computer 19, if it collects a prescribed number of sensor unit data Fx, Fy, Fz and line sensor data wireX, wireY, wireZ, performs a regression calculation of a regression formula that sets the sensor unit data Fx, Fy, Fz as target variables (target parameters) and the line sensor data wireX, wireY, wireZ as explanatory variables (explanatory parameters) for each of the sensor unit data Fx, Fy, Fz (step S19).

[0096] Here, the regression formula that sets the sensor unit data Fx, Fy, Fz as target variables is defined by the following formulas, respectively.

[0097] Fx ~ Cx1 - wireX + Cx2 - wireY + Cx3 - wireZ + Cx4

[0098] Fy ~ Cy1 - wireX + Cy2 - wireY + Cy3 - wireZ + Cy4

[0099] Fz ~ Cz1 - wireX + Cz2 - wireY + Cz3 - wireZ + Cz4

[0100] Here, Cx1, Cx2, Cx3, Cx4, Cy1, Cy2, Cy3, Cy4, Cz1, Cz2, Cz3, Cz4 are calibration coefficients.

[0101] Then, the calibration coefficients that correspond to the calculated regression coefficients are determined (step S20).

[0102] Next, if the processing of the processing device 20 and the data collection are completed (step S21), the signal collection / analysis computer 19 stops the processing tool and ends the processing (step S22).

[0103] Next, an example of the operation of the embodiment will be described.

[0104] In the following description, it is assumed that the calibration coefficient described above is determined.

[0105] Figure 6 is a graph that explains the relationship between the number of guide grooves in the linear sensor and the output signal.

[0106] Figure 6 (A) of is a graph that explains the output signal in the case where the guide grooves are one.

[0107] In this case, Figure 6 (A1) of is a graph that explains the output signal of the linear sensor (for example, the first linear sensor 11) in the case where the guide grooves are one, Figure 6 (A2) of is Figure 6 (A1) of is a partial enlarged view of

[0108] In Figure 6 (A1) of, Figure 6 (A2) of, the vertical axis is the linear sensor output value (unit: V), and the horizontal axis is time.

[0109] In addition, Figure 6 (A3) of is a graph that explains the output signal of the bench measuring unit, Figure 6 (A4) of is Figure 6 (A3) of is a partial enlarged view of

[0110] In Figure 6 (A3) of, Figure 6 (A4) of, the vertical axis is the cutting force (unit: N), and the horizontal axis is time.

[0111] As indicated by the double-headed arrow in Figure 6 (A3), it is known that in the bench measuring unit, the cutting (machining) during the machining of the machining device 20 is detected as in the case shown in Figure 6 (A1). Also, in the enlarged view shown in Figure 6 (A2), unlike the output signal of Figure 6 (A4), the peak value of the cutting force that is periodically generated in association with the rotation and movement of the machining tool TL during the cutting (machining) is a signal that can be clearly grasped.

[0112] Figure 6 (B) of is a graph that explains the output signal in the case where the guide grooves are four as shown in Figure 7 . The machining conditions are the same as in Figure 8 (A).

[0113] In Figure 7 (B1) of, Figure 8 (B2) of, the vertical axis is the linear sensor output value (unit: V), and the horizontal axis is time. In addition, inFigure 7 (B3) Figure 8 In (B4), the vertical axis represents the cutting force (unit: N), and the horizontal axis represents time.

[0114] When guide grooves 32A, 32B, 32C, and 32D are set as guide grooves 32, the pressure-bearing length of the piezoelectric sensor 31 of the line sensor (e.g., the first line sensor 11) becomes four times, and therefore the output voltage becomes four times.

[0115] The results show that during the cutting (machining) process of the machining device 20, if Figure 8 As shown in (B1), with Figure 7 Compared to case (A1), the output detects cutting (machining) and has a signal with four times the amplitude, even with... Figure 7 The detection signal comparison of the benchtop measuring unit shown in (B4) also has a large amplitude, which can obtain high-precision detection results.

[0116] Moreover, such as Figure 8 As shown in (B2), with Figure 7 Compared to the output signal of (A2), it is more clearly defined that the peak value of the cutting force generated periodically with the rotation and movement of the machining tool TL during cutting (machining) is a signal that can be clearly grasped.

[0117] Thus, according to this embodiment, a highly sensitive sensor can be constructed with a simple structure (by increasing the number of guide grooves to extend the effective length of the piezoelectric sensor 31), thereby enabling the construction of a highly sensitive and accurate measurement system.

[0118] Figure 8 This is one of the illustrations showing a measurement performed under the same conditions as during calibration.

[0119] Figure 7 This is an explanatory diagram (Part Two) showing the measurement performed under the same conditions as during calibration.

[0120] exist Figure 8 and Figure 7 In the graph, the vertical axis represents the cutting force (unit: N), and the horizontal axis represents time. Additionally, Figure 8 and Figure 7 The difference is the timeline scale. Figure 8 The timeline is Figure 9 Ten times the timeline.

[0121] In addition, the conditions for obtaining these data are as follows: the diameter of the machining tool TL is 2mm, the speed of the tool spindle 20B is 8000rpm, the feed rate of the worktable is 150mm, the axial depth of the machining tool is 0.2mm, and the radial depth of the machining tool is 2.0mm.

[0122] Figure 10 (A) of FIG. 6 and Figure 9 (A) of FIG. 6 is a correspondence explanatory view of the X-axis direction component of the cutting force variation corresponding to the bench measuring unit 17 and the X-axis direction component of the cutting force variation corresponding to the sensor unit (= the first linear sensor 11 to the third linear sensor 13).

[0123] Figure 10 (B) of FIG. 6 and Figure 8 (B) of FIG. 6 is a correspondence explanatory view of the Y-axis direction component of the cutting force variation corresponding to the bench measuring unit 17 and the Y-axis direction component of the cutting force variation corresponding to the sensor unit (= the first linear sensor 11 to the third linear sensor 13).

[0124] Figure 9 (C) of FIG. 6 and Figure 10 (C) of FIG. 6 is a correspondence explanatory view of the Z-axis direction component of the cutting force variation corresponding to the bench measuring unit 17 and the Z-axis direction component of the cutting force variation corresponding to the sensor unit (= the first linear sensor 11 to the third linear sensor 13).

[0125] Figure 8 (D) of FIG. 6 and Figure 9 (D) of FIG. 6 is a correspondence explanatory view of the square root of the sum of the squares of the X-axis direction component, the Y-axis direction component and the Z-axis direction component of the cutting force variation corresponding to the bench measuring unit 17, that is, the resultant force and the square root of the sum of the squares of the X-axis direction component, the Y-axis direction component and the Z-axis direction component of the cutting force variation corresponding to the sensor unit (= the first linear sensor 11 to the third linear sensor 13), that is, the resultant force.

[0126] As shown in Figure 10 and Figure 9 , by performing linear regression on the output signals of the first linear sensor 11 to the third linear sensor 13 based on the measurement data of a prescribed time (for example, 10 seconds) as described above, the calibration coefficients Cx1, Cx2, Cx3, Cx4, Cy1, Cy2, Cy3, Cy4, Cz1, Cz2, Cz3, Cz4 are determined, and thus the machining waveform (cutting waveform) based on the output signals of the first linear sensor 11 to the third linear sensor 13 is well reproduced including the change in the suddenly generated peak value.

[0127] Figure 10 is a explanatory view of the measurement results in the case where the machining condition at the time of calibration is changed.

[0128] Figure 9 is a explanatory view of the measurement results in the case where the machining condition at the time of calibration is changed.

[0129] exist Figure 10 and Figure 9 In the graph, the vertical axis represents the detected cutting force (unit: N), and the horizontal axis represents time. Additionally, in... Figure 10 as well as Figure 9 , Figure 10 In the meantime, the axial cut-in amount is 0.2mm, which is constant, while the radial cut-in amount is different.

[0130] More specifically, in Figure 9 In this case, the radial cut-in depth is 2.0 mm, but... Figure 10 In this case, the radial cut-in is 1.0 mm. Figure 8 In the case of 0.5mm.

[0131] ​ (A) and ​ (A) is a diagram illustrating the correspondence between the X-axis component of the cutting force variation corresponding to the benchtop measuring unit 17 and the X-axis component of the cutting force variation corresponding to the sensor units (= first line sensor 11 to third line sensor 13).

[0132] ​ (B) and ​ (B) is a diagram illustrating the correspondence between the Y-axis component of the cutting force variation corresponding to the benchtop measuring unit 17 and the Y-axis component of the cutting force variation corresponding to the sensor units (= first line sensor 11 to third line sensor 13).

[0133] ​ (C) and ​ (C) is a diagram illustrating the correspondence between the Z-axis component of the cutting force variation corresponding to the benchtop measuring unit 17 and the Z-axis component of the cutting force variation corresponding to the sensor units (= first line sensor 11 to third line sensor 13).

[0134] ​ (D) and ​ (D) is a diagram illustrating the correspondence between the square root of the sum of the squares of the X-axis, Y-axis and Z-axis components of the cutting force variation corresponding to the benchtop measuring unit 17 (i.e., the resultant force) and the square root of the sum of the squares of the X-axis, Y-axis and Z-axis components of the cutting force variation corresponding to the sensor units (= first line sensor 11 to third line sensor 13) (i.e., the resultant force).

[0135] like ​ and ​ As can be seen, even in the case of ​In the case where the processing conditions (the amount of radial cut in this case) were changed from the processing conditions at the time of calibration, the measurement results of the table measurement unit 17 and the measurement results based on the output signals of the first to third line sensors 11 to 13 were also consistent, and the processing waveforms (cutting waveforms) based on the output signals of the first to third line sensors 11 to 13 were reproduced well including the change in the peak value that was suddenly generated.

[0136] That is, according to the present embodiment, once the sensitivity coefficient is determined, even if the processing conditions are changed, the conversion can be appropriately performed, and the processing waveforms can be accurately output.

[0137] Therefore, according to the present embodiment, in the state diagnosis related to the processing, high sensitivity and high accuracy of the force sensation detection can be achieved, and further, early detection of abnormalities and the like can be easily and inexpensively achieved.

[0138] The signal collection / analysis computer of the measurement system of the present embodiment has a control device such as a CPU, a storage device such as a ROM (Read Only Memory) and a RAM, and an external storage device such as an HDD and a CD drive, and is a hardware structure using a general computer.

[0139] The program executed by the signal collection / analysis computer of the present embodiment is provided by recording a file in an installable format or an executable format in a USB memory, a semiconductor storage device such as an SSD, or a computer-readable recording medium such as a DVD (Digital Versatile Disk).

[0140] In addition, the program executed by the signal collection / analysis computer of the present embodiment can be stored in a computer connected to a network such as the Internet, and provided by downloading via the network. In addition, the program executed by the signal collection / analysis computer of the present embodiment can be provided or distributed via a network such as the Internet.

[0141] In addition, the program of the signal collection / analysis computer of the present embodiment can be provided by being pre-installed in a ROM or the like.

[0142] The several embodiments of the present application have been described, but these embodiments are presented as examples and are not intended to limit the scope of the application. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made within the scope of the gist of the application. These embodiments and modifications thereof are included in the scope and gist of the application, and are included in the scope of the application and equivalents thereof recited in the claims.

Claims

1. A sensor unit, characterized in that, have: A linear piezoelectric sensor; and The measuring section has a guide groove for holding a portion of the piezoelectric sensor and a contact surface for contacting the object being measured at a specified pressure. The piezoelectric sensor includes: The portion located within the area of ​​the contact surface used for measuring the object being measured; and Another portion extending from the guide groove and located outside the range of the abutment surface; The sensor unit includes a buffer holding section that holds the other part of the piezoelectric sensor in a buffered state to absorb the vibration of the other part.

2. The sensor unit according to claim 1, characterized in that, Multiple guide grooves are provided. The lengths of the multiple guide slots are set to be the same.

3. The sensor unit according to claim 1 or 2, characterized in that, The width of the guide groove is set to a width that does not impede the deformation of the piezoelectric sensor within the guide groove in conjunction with pressure.

4. The sensor unit according to claim 1 or 2, characterized in that, The measuring unit includes: The abutting portion has the abutting surface; and The pressurizing section pushes the abutting section against the object to be measured at a specified pressure.

5. The sensor unit according to claim 3, characterized in that, The measuring unit includes: The abutting portion has the abutting surface; and The pressurizing section pushes the abutting section against the object to be measured at a specified pressure.

6. A sensor system, characterized in that, have: A plurality of sensor units as described in any one of claims 1 to 5 are provided with the contact surfaces on a plane perpendicular to mutually different and intersecting axes, and each of the contact surfaces contacts the object to be measured. Multiple amplifiers are connected to the piezoelectric sensors of the multiple sensor units to amplify and output the output signals of the piezoelectric sensors; as well as The analysis device analyzes and detects the state based on the output signals of the multiple amplifiers.

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