Cutting tool

Abstract

A cutting tool has a shaft portion and a sensor portion configured to surround a part of the length direction of the shaft portion. The sensor portion includes a sensor module including a plurality of first sensors that detect a first physical quantity of the shaft portion, a substrate electrically connected to the first sensors, and a wireless communication portion electrically connected to the substrate and that transmits a signal including information of the first physical quantity detected by the first sensors to the outside, and a housing that accommodates the sensor module. The region of the shaft portion surrounded by the sensor portion includes a first region that is a 4n-sided polygon when viewed in the direction along the rotation axis. The above n is a natural number of 2 or more. When viewed in the direction along the rotation axis, the plurality of first sensors are disposed on at least two faces of the outer peripheral surface of the first region that are 90° to each other by a perpendicular line of the rotation axis among each face of the outer peripheral surface of the first region corresponding to each side of the 4n-sided polygon.

Description

Technical Field

[0001] This disclosure relates to cutting tools. Background Technology

[0002] It is known that in machining based on cutting tools, the state of the cutting tool is known by measuring the physical quantities of the cutting tool using sensors (for example, see U.S. Patent Application Publication No. 2015 / 0261207 (Patent Document 1), Japanese Patent Application Publication No. 2018-54611 (Patent Document 2), Japanese Patent Application Publication No. 2009-285804 (Patent Document 3), International Publication No. 2017 / 002762 (Patent Document 4), Japanese Patent No. 5988066 (Patent Document 5), Utility Model Registration No. 3170029 (Patent Document 6), Japanese Patent Application Publication No. 2015-77658 (Patent Document 7), International Publication No. 2015 / 056495 (Patent Document 8), European Patent Application Publication No. 3292929 (Patent Document 9), and European Patent Application Publication No. 3292930 (Patent Document 10)).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: U.S. Patent Application Publication No. 2015 / 0261207

[0006] Patent Document 2: Japanese Patent Application Publication No. 2018-54611

[0007] Patent Document 3: Japanese Patent Application Publication No. 2009-285804

[0008] Patent Document 4: International Publication No. 2017 / 002762

[0009] Patent Document 5: Japanese Patent Application Publication No. 2016-221665

[0010] Patent Document 6: Japanese Utility Model Registration No. 3170029

[0011] Patent Document 7: Japanese Patent Application Publication No. 2015-77658

[0012] Patent Document 8: International Publication No. 2015 / 056495

[0013] Patent Document 9: European Patent Application Publication No. 3292929

[0014] Patent Document 10: European Patent Application Publication No. 3292930 Summary of the Invention

[0015] The cutting tool according to this disclosure includes: a shaft extending from a first end to a second end along a rotation axis; and a sensor portion configured to surround a portion of the shaft in its length direction. This cutting tool cuts a workpiece by rotating about the rotation axis of the shaft. The sensor portion includes: a sensor module comprising a plurality of first sensors for detecting a first physical quantity of the shaft, a substrate electrically connected to the first sensors, and a wireless communication portion electrically connected to the substrate for transmitting a signal containing information about the first physical quantity detected by the first sensors to the outside; and a housing housing the sensor module. The region of the shaft surrounded by the sensor portion comprises a first region that is a 4n-sided polygon when viewed along the rotation axis. Here, n is a natural number greater than or equal to 2. When viewed along the rotation axis, the plurality of first sensors are disposed on at least two of the outer peripheral surfaces of the first region corresponding to the sides of the 4n-sided polygon, forming 90° angles with each other via the perpendicular line of the rotation axis. Attached Figure Description

[0016] Figure 1 It is a schematic three-dimensional diagram showing the structure of a cutting tool.

[0017] Figure 2 It is a schematic three-dimensional diagram showing the structure of the shaft.

[0018] Figure 3 It means from and Figure 2 A schematic three-dimensional view of the structure of the shaft when viewed from different viewpoints.

[0019] Figure 4 This is a top view showing the structure of the shaft when viewed from the first end side along the direction of rotation.

[0020] Figure 5 This is a top view showing the structure of the shaft when viewed from the second end side along the axis of rotation.

[0021] Figure 6 It is a top view showing the structure of the shaft when viewed in a direction perpendicular to the axis.

[0022] Figure 7 It means along Figure 5 A schematic sectional view of the section of line segment VII-VII.

[0023] Figure 8 This is a schematic cross-sectional view showing the structure near the sensor unit.

[0024] Figure 9 This is a schematic three-dimensional diagram showing the structure of the strain sensor component.

[0025] Figure 10 This is a top view showing the structure of the substrate module.

[0026] Figure 11 It means along Figure 10 A schematic sectional view of the section of line segment XI-XI.

[0027] Figure 12 This is a top view showing the state in which the baseboard module is mounted on the shaft.

[0028] Figure 13 It is a schematic three-dimensional drawing showing the structure of the main body of the shell.

[0029] Figure 14 This is a schematic three-dimensional drawing showing the structure of the first fixed component.

[0030] Figure 15 This is a schematic three-dimensional drawing showing the structure of the second fixed component.

[0031] Figure 16 This is a schematic three-dimensional drawing showing the structure of the cover (upper wall).

[0032] Figure 17 This is a top view showing the structure of the substrate module when a modified substrate is used.

[0033] Figure 18 It means along Figure 17 A schematic sectional view of the section of line segment XVIII-XVIII.

[0034] Figure 19 This is a schematic perspective view showing the structure of the cutting tool in another embodiment. Detailed Implementation

[0035] [The problem this disclosure aims to solve]

[0036] From the perspective of gaining a detailed understanding of the state of a cutting tool during machining, there is a need to acquire more useful data through sensors. One of the objectives of this disclosure is to provide a cutting tool capable of acquiring more useful data through sensors.

[0037] [The Effects of This Disclosure]

[0038] According to the cutting tool disclosed herein, more useful data can be acquired through sensors.

[0039] [Description of embodiments of this disclosure]

[0040] First, embodiments of the present disclosure will be described. The cutting tool of the present disclosure includes: a shaft extending from a first end to a second end along a rotation axis; and a sensor section configured to surround a portion of the shaft in its length direction. This cutting tool cuts a workpiece by rotating about the rotation axis of the shaft. The sensor section includes: a sensor module comprising a plurality of first sensors for detecting a first physical quantity of the shaft, a substrate electrically connected to the first sensors, and a wireless communication section electrically connected to the substrate and transmitting a signal containing information about the first physical quantity detected by the first sensors to the outside; and a housing housing the sensor module. The region of the shaft surrounded by the sensor section comprises a first region that is a 4n-sided polygon when viewed along the rotation axis. Here, n is a natural number of 2 or more. When viewed along the rotation axis, the plurality of first sensors are disposed on at least two of the outer peripheral surfaces of the first region corresponding to the sides of the 4n-sided polygon, forming 90° angles with each other via the perpendicular line of the rotation axis.

[0041] In the cutting tool of this disclosure, the region of the shaft surrounded by the sensor section comprises a first region that is a 4n-sided polygon (n is a natural number of 2 or more) when viewed along the direction of the rotation axis. Furthermore, multiple first sensors that detect the same physical quantity (the first physical quantity) are arranged on at least two surfaces of the outer peripheral surface of the first region, corresponding to each side of the 4n-sided polygon, and forming a 90° angle with each other through the perpendicular line of the rotation axis. Thus, the sensors detecting the same physical quantity are configured to have a 90° phase difference during rotation about the rotation axis. As a result, the first physical quantity in a plane perpendicular to the rotation axis can be appropriately measured. This measured physical quantity is useful for monitoring the state of the cutting tool during machining. As described above, according to the cutting tool of this disclosure, more useful data can be acquired through sensors.

[0042] In the aforementioned cutting tool, when viewed along the direction of the rotation axis, the angles formed by the perpendicular lines through the rotation axis to each face of the outer peripheral surface of the first region corresponding to each circumferentially adjacent side of the 4n-sided polygon are equal. This readily ensures the symmetry of the outer peripheral surface of the first region where the sensor can be installed relative to the rotation axis.

[0043] Alternatively, in the cutting tool described above, when viewed along the rotation axis, the substrate is configured such that its outer peripheral surface, corresponding to multiple sides of the 4n-sided polygon, extends along the outer peripheral surface of the first region. This makes it easier to prevent the substrate module from moving relative to the axis. As a result, the accuracy of the physical quantities obtained from the first sensor is improved.

[0044] Alternatively, in the aforementioned cutting tool, a first recess may be formed on the outer circumferential surface of the shaft. Alternatively, the first sensor may be housed within the first recess. This simplifies the installation of the first sensor.

[0045] Alternatively, in the aforementioned cutting tool, the first sensor may be a strain sensor. The sensor configuration of this disclosure is suitable for strain measurement.

[0046] Alternatively, in the aforementioned cutting tool, a second recess may be formed on the outer circumferential surface of the shaft. Alternatively, the first sensor may be configured to span the second recess. When the first sensor is a strain sensor, by configuring it to span the second recess in this way, strain can be easily measured with high accuracy.

[0047] Alternatively, in the aforementioned cutting tool, the first sensor may be a strain sensor. Alternatively, a first recess and a second recess, deeper than and overlapping the first recess, may be formed on the outer circumferential surface of the shaft. Alternatively, the first sensor may be configured to span the second recess and be housed within the first recess. This simplifies the installation of the first sensor and facilitates high-precision strain measurement using the first sensor.

[0048] Alternatively, in the cutting tool described above, the second recess can be a groove extending circumferentially along the shaft. Alternatively, the first recess can extend in a direction orthogonal to the second recess. This simplifies the installation of the first sensor and makes it easier to measure strain with high precision using the first sensor.

[0049] Alternatively, in the aforementioned cutting tool, the first sensor may be an acceleration sensor. The sensor configuration of this disclosure is suitable for acceleration measurement.

[0050] Alternatively, in the aforementioned cutting tool, the sensor module may further include multiple second sensors that detect a second physical quantity on the shaft that differs from the first physical quantity. Alternatively, the substrate may be electrically connected to the second sensors. Alternatively, a wireless communication unit may be electrically connected to the substrate, transmitting a signal containing information about the second physical quantity detected by the second sensors to the outside.

[0051] In this way, by setting up a second sensor to detect a second physical quantity different from the first physical quantity, it is possible to simultaneously grasp both physical quantities. As a result, it is possible to acquire more useful data for understanding the state of the cutting tool during machining through the sensor.

[0052] Alternatively, in the aforementioned cutting tool, the first sensor can be a strain sensor that detects strain as a first physical quantity. Or, the second sensor can be an acceleration sensor that detects acceleration as a second physical quantity. Thus, both the strain and acceleration of the cutting tool can be simultaneously measured.

[0053] Alternatively, in the cutting tool described above, the first and second sensors can be positioned on the outer peripheral surface of the first region corresponding to the different sides of the 4n-sided polygon. This simplifies the sensor placement.

[0054] Alternatively, in the aforementioned cutting tool, the sensor module may also include wiring connected to the first sensor. Alternatively, the wiring may connect the first sensor to the substrate in a sag-like manner. In this way, by giving the wiring of the first sensor sag, the first sensor can be easily set up without adjusting the wiring length.

[0055] Alternatively, in the aforementioned cutting tool, the sensor module may further include an AD converter disposed on the substrate. Alternatively, the thickness of the substrate in a fourth region (excluding the second region where the wireless communication unit is mounted and the third region where the AD converter is mounted), is less than the thickness in the second and third regions, and the substrate is bent in the fourth region. This prevents the relatively large components, such as the wireless communication unit and the AD converter, from peeling off due to substrate deformation, and makes it easier to use a substrate suitable for installation.

[0056] Alternatively, in the aforementioned cutting tool, the substrate can be a rigid substrate. Alternatively, a groove can be formed in the fourth region of the substrate to connect the two ends along the direction of the rotation axis. This makes it easier to reduce the thickness of the fourth region compared to the second and third regions.

[0057] Alternatively, in the aforementioned cutting tool, the substrate includes: a main body portion, which is a flexible substrate; and a reinforcing plate disposed in the second and third regions, wherein the Young's modulus of the reinforcing plate is greater than that of the main body portion. Therefore, compared to the second and third regions, it is easier to reduce the thickness of the fourth region.

[0058] [Detailed description of the embodiments of the invention in this application]

[0059] Next, embodiments of the cutting tool according to this disclosure will be described with reference to the accompanying drawings. It should be noted that in the following drawings, the same or equivalent parts are labeled with the same reference numerals, and their descriptions will not be repeated.

[0060] (A summary of the structure of a cutting tool)

[0061] Figure 1 This is a schematic three-dimensional drawing showing the structure of a cutting tool. First, refer to... Figure 1The structure of the cutting tool will be described in general. The cutting tool 1 in this embodiment includes a shaft portion 10 and a sensor portion 20. The shaft portion 10 extends from a first end 10A to a second end 10B along a rotation axis A. The sensor portion 20 is configured to surround a portion of the shaft portion 10 in the longitudinal direction. In the shaft portion 10, a plurality of recesses 13 (four in this case) are formed at equal intervals in the circumferential direction, opening at the first end 10A and on the outer circumferential surface. A cutting insert 91 is mounted on the wall surface defined by the recesses 13. By rotating the cutting tool 1 about the rotation axis A, the cutting insert 91 comes into contact with the workpiece (not shown), thereby enabling the workpiece to be machined. In other words, the cutting tool 1 is a cutting tool that cuts the workpiece by rotating about the rotation axis A of the shaft portion 10.

[0062] (Structure of the shaft)

[0063] Next, the details of each part of the cutting tool will be explained. Figure 2 This is a schematic perspective view showing the structure of the shaft portion as viewed from the second end 10B side. Figure 3 This is a schematic perspective view showing the structure of the shaft portion as viewed from the first end 10A side. Figure 4 This is a top view showing the structure of the shaft when viewed from the first end side along the direction of rotation. Figure 5 This is a top view showing the structure of the shaft when viewed from the second end side along the axis of rotation. Figure 6 It is a top view showing the structure of the shaft when viewed in a direction perpendicular to the axis. Figure 7 It means along Figure 5 A schematic sectional view of line segment VII-VII. (Refer to...) Figures 2-7 The structure of the shaft 10 will be explained.

[0064] Reference Figure 2 as well as Figure 3 The shaft portion 10 includes a main body portion 11 and an expanded diameter portion 12 serving as a first region. The main body portion 11 has a cylindrical shape. The rotation axis A is aligned with the central axis of the main body portion 11. The expanded diameter portion 12 is a portion with a diameter larger than that of the main body portion 11. The position of the expanded diameter portion 12 in the longitudinal direction of the main body portion 11 is not particularly limited, but in this embodiment, it is disposed in the central portion in the longitudinal direction of the main body portion 11. The expanded diameter portion 12 is disposed in the region of the shaft portion 10 surrounded by the sensor portion 20.

[0065] Reference Figures 2-4 As described above, a cutting blade 91 is mounted on the wall surface of the recess 13 of the shaft portion 10. The cutting blade 91 is fixed to the shaft portion 10 by inserting a screw 92 into the threaded hole formed in the cutting blade 91 and tightening it.

[0066] Reference Figures 2-6 The enlarged diameter portion 12 has an octagonal prism shape. (See reference...) Figure 4 as well as Figure 5 The enlarged diameter portion 12 has an octagonal shape when viewed along the direction of the rotation axis A. More specifically, in a cross-section perpendicular to the rotation axis A, the enlarged diameter portion 12 has an octagonal shape formed by removing four isosceles right triangles of the same shape from the four corners of a square. The rotation axis A passes through the centroid of this octagon. The shape of this octagon is the same in the direction along the rotation axis A. The central axis of the main body portion 11 coincides with the central axis of the enlarged diameter portion 12. Here, the central axis of the enlarged diameter portion 12 refers to a straight line passing through the centroid of the aforementioned octagon.

[0067] Reference Figure 4 as well as Figure 5 When viewed along the direction of rotation axis A, the octagon is composed of alternately arranged outer peripheral surfaces 12A corresponding to the longer sides and outer peripheral surfaces 12B corresponding to the shorter sides. Among the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12 that are adjacent to each other in the circumferential direction of the octagon, the perpendicular line L passing through rotation axis A of the outer peripheral surface 12A... A The perpendicular line L passing through the rotation axis A to the outer peripheral surface 12B. B The angles θ formed by the octagons are equal. Specifically, angle θ is 45°. It should be noted that the shape of the octagons is not limited to the shape described above. When viewed along the direction of the rotation axis A, the lengths of the outer circumferential surfaces 12A and 12B can also be the same.

[0068] Reference Figures 2-6 Each outer peripheral surface 12B has a first recess 16 extending in the direction along the rotation axis A. The bottom surface 16A of the first recess 16 is a plane. The first recess 16 is positioned perpendicular to line L. B The first recess 16 extends through the outer peripheral surface 12B along the direction of rotation axis A. A second recess 15 extending circumferentially along the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12 is formed. The second recess 15 overlaps with the first recess 16. The second recess 15 intersects (orthogonally) with the first recess 16. The second recess 15 is formed covering the entire circumference of the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12. That is, the second recess 15 is formed in a ring shape.

[0069] Reference Figure 6 as well as Figure 7The depth d2 of the second recess 15 is greater than the depth d1 of the first recess 16. A first minor diameter portion 11A, smaller than the others, is formed at the boundary between the first end portion 10A of the main body portion 11 and the expanded diameter portion 12. A second minor diameter portion 11B, smaller than the others, is formed at the boundary between the second end portion 10B of the main body portion 11 and the expanded diameter portion 12. A through hole 10C is formed in the shaft portion 10, extending through the shaft portion 10 in the direction along the rotation axis A. The through hole 10C extends in a manner that includes the rotation axis A.

[0070] (Structure of the sensor section)

[0071] Next, refer to Figures 8 to 16 The structure of the sensor unit 20 will be described below. (Refer to...) Figure 8 The sensor unit 20 includes a sensor module 80 and a housing 21 that houses the sensor module 80. The sensor module 80 includes a plurality of strain sensors 31 serving as a plurality of first sensors, a substrate 49 electrically connected to the strain sensors 31, and a wireless communication unit 51 electrically connected to the substrate 49 (see reference). Figure 10 , Figure 11 The strain sensor 31 detects the strain of the shaft portion 10 as a first physical quantity. The wireless communication unit 51 transmits a signal containing information about the strain detected by the strain sensor 31 to the outside.

[0072] Reference Figure 9 The strain sensor 31 constitutes the strain sensor component 30. The strain sensor component 30 includes the strain sensor 31 and a wiring 32 connected to the strain sensor 31 and having a connector 33 at its front end. The wiring 32 has a strip-like shape. The strain sensor 31 is disposed near one end of the wiring 32. The connector 33 is disposed at the other end of the wiring 32.

[0073] Reference Figure 10 as well as Figure 11 The substrate 49 constitutes the substrate module 40. The substrate 49 includes a substrate body made of an insulator such as resin and a circuit pattern (not shown) of a conductive material such as copper formed on the surface of the substrate body. The substrate module 40 includes the substrate 49, a wireless communication unit 51, an accelerometer 52 as a second sensor, a socket 53, and an AD converter 54. The wireless communication unit 51, the accelerometer 52, the socket 53, and the AD converter 54 are disposed on one main surface of the substrate 49 and electrically connected to the substrate 49 (the circuit pattern of the substrate 49). The accelerometer 52 detects the acceleration of the shaft portion 10 as a second physical quantity. Multiple accelerometers 52 are disposed on the substrate 49. The wireless communication unit 51 is electrically connected to the accelerometer 52 via the substrate 49. The wireless communication unit 51 transmits a signal containing information about the acceleration of the shaft portion 10 detected by the accelerometer 52 to the outside.

[0074] The substrate 49 is a rigid substrate. The substrate 49 has a strip-like shape. The substrate 49 includes a first region 41, a second region 42, a third region 43, a fourth region 44, a fifth region 45, a sixth region 46, a seventh region 47, and an eighth region 48. Regions 41 to 48 are arranged sequentially along the length of the substrate 49. A wireless communication unit 51 and an accelerometer 52 are mounted in the first region 41. A socket 53 is mounted in the second region 42. An accelerometer 52 is mounted in the third region 43. A socket 53 is mounted in the fourth region 44. An accelerometer 52 and an AD converter 54 are mounted in the fifth region 45. A socket 53 is mounted in the sixth region 46. An accelerometer 52 is mounted in the seventh region 47. A socket 53 is mounted in the eighth region 48.

[0075] A bendable region 49A, with a smaller thickness than other portions, is formed between adjacent first regions 41 to eighth regions 48. The bendable region 49A is a groove connecting the two ends of the substrate 49 in the width direction (perpendicular to the length direction). First region 41 is the second region housing the wireless communication unit 51. Fifth region 45 is the third region housing the AD converter 54. The bendable region 49A is the fourth region, with a smaller thickness than the second and third regions. The lengths of the first region 41, third region 43, fifth region 45, and seventh region 47 in the length direction of the substrate 49 are formed to correspond to the length of the long side, i.e., the outer peripheral surface 12A, of the octagon when viewed along the direction of rotation axis A. The lengths of the second region 42, fourth region 44, sixth region 46, and eighth region 48 in the length direction of the substrate 49 are formed to correspond to the length of the short side, i.e., the outer peripheral surface 12B, of the octagon when viewed along the direction of rotation axis A.

[0076] Next, the arrangement of the strain sensor component 30 and the substrate module 40 relative to the shaft portion 10 will be described. The strain sensor component 30 is configured such that the strain sensor 31 spans the second recess 15 and is received within the first recess 16 (see reference). Figure 2 , Figure 4 , Figure 8 (etc.). Strain sensor components 30 are respectively disposed on four outer peripheral surfaces 12B. As a result, when viewed along the direction of rotation axis A, the strain sensor 31 is positioned on the outer peripheral surfaces of the enlarged diameter portion 12 corresponding to each side of the octagon, along the perpendicular line L passing through the rotation axis A. B The entirety of the outer peripheral surface 12B (the outer peripheral surface corresponding to the short side) of the expanded diameter portion 12 that is 90° to each other.

[0077] Reference Figure 8 as well as Figure 12The substrate module 40 is wound around the expanded diameter portion 12 such that the main surface of the substrate 49 opposite to the side housing the wireless communication unit 51, the accelerometer 52, the socket 53, and the AD converter 54 is in contact with the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12. At this time, the first region 41, the third region 43, the fifth region 45, and the seventh region 47 are disposed on the outer peripheral surface 12A, and the second region 42, the fourth region 44, the sixth region 46, and the eighth region 48 are disposed on the outer peripheral surface 12B. In addition, the substrate 49 is bent at the bendable region 49A, which is a groove connecting the two ends along the direction of rotation axis A (a groove connecting the two ends in the width direction).

[0078] As a result, when viewed along the direction of rotation axis A, the substrate 49 is configured along the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12. The socket 53 is disposed on the substrate 49 located on the outer peripheral surface 12B. Furthermore, the connector 33 at the end of the wiring 32 connected to the strain sensor 31 is connected to the socket 53. Thus, the substrate 49 is electrically connected to the strain sensor 31. Figure 8 As shown, wiring 32 crosses substrate 49 in the width direction (along the direction of rotation axis A). Wiring 32 is formed in an arched shape. That is, wiring 32 connects strain sensor 31 and socket 53 in a sag manner.

[0079] Accelerometer 52 is disposed on the first region 41, the third region 43, the fifth region 45, and the seventh region 47 of the substrate 49. Therefore, by disposing the substrate module 40 on the expanded diameter portion 12 as described above, when viewed along the direction of rotation axis A, the accelerometer 52 is disposed on the outer peripheral surface of the expanded diameter portion 12 corresponding to each side of the octagon, along the perpendicular line L passing through rotation axis A. A The entire outer peripheral surface 12A (the outer peripheral surface corresponding to the long side) of the expanded diameter portion 12, which is at a 90° angle to each other. That is, the strain sensor 31 and the acceleration sensor 52 are disposed on the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12, which are different from the sides of the octagon.

[0080] Reference Figure 10 In this embodiment, the accelerometer 52 is disposed at the center of the short side of a rectangular planar substrate 49. As a result, referring to... Figure 10 as well as Figure 8 In the direction along the rotation axis A, the acceleration sensor 52 and the strain sensor 31 are arranged at the same position. This reduces the axial length required for sensor installation. Consequently, the sensor section 20 can be reduced in size. Here, the state that "the acceleration sensor 52 and the strain sensor 31 are arranged at the same position along the rotation axis A" means, referring to... Figure 8 as well as Figure 10The measurement range a (specifically, the range where resistive wiring for detecting acceleration) of the accelerometer 52 along the direction of rotation axis A overlaps at least partially with the measurement range b (specifically, the range where resistive wiring for detecting strain) of the strain sensor 31. The positional relationship between the accelerometer 52 and the strain sensor 31 along the direction of rotation axis A can also be varied considering the ease of detecting acceleration and strain. For example, along the direction of rotation axis A, the strain sensor 31 can also be positioned further away from the first end 10A than the accelerometer 52 (on the side further away from the cutting blade 91). Figure 8 (The upper side is in the middle). The strain of the shaft portion 10 due to cutting increases as it moves further away from the cutting blade. The acceleration of the shaft portion 10 due to cutting increases at a position closer to the cutting blade. Therefore, by adopting such a configuration, the sensitivity of strain and acceleration detection by the strain sensor 31 and the acceleration sensor 52 is improved. On the other hand, in the direction along the rotation axis A, the strain sensor 31 can also be configured at a position closer to the first end 10A than the acceleration sensor 52 (on the side closer to the cutting blade 91); Figure 8 (Lower side of the shaft). When the shaft portion 10 is relatively long, in the above configuration, there is a situation where the strain of the shaft portion 10 at the location where the strain sensor 31 is disposed becomes excessive. In such cases, by disposing the strain sensor 31 closer to the first end portion 10A than the acceleration sensor 52, the magnitude of the strain at the location where the strain sensor 31 is disposed can be made to be within the range that the strain sensor 31 can easily detect.

[0081] Additionally, refer to Figure 8 as well as Figure 12 In this embodiment, the strain sensor 31 includes a temperature sensor. That is, in this embodiment, the strain sensor 31 and the temperature sensor are integrated into one unit. The temperature sensor does not necessarily need to be integrated with the strain sensor 31; it can also be a separate unit. In this case, refer to... Figure 8 Along the direction of rotation axis A, the temperature sensor is positioned at the same location as the strain sensor 31. More specifically, refer to... Figure 8 as well as Figure 12A temperature sensor is disposed at any position within an annular region (a strip-shaped region in the outer peripheral surfaces 12A and 12B of the expanded diameter section 12 with a width equal to the measurement range b of the strain sensor 31) on the direction along the rotation axis A, corresponding to the measurement range b of the strain sensor 31. While the temperature sensor is not essential in the cutting tool of this disclosure, its use allows for the detection of the temperature in the region corresponding to the measurement range b of the strain sensor 31, either at the location where the strain sensor 31 is disposed or in the outer peripheral surfaces 12A and 12B of the expanded diameter section 12. Based on the temperature detected by the temperature sensor, the thermal strain in the region corresponding to the measurement range b of the strain sensor 31, either at the location where the strain sensor 31 is disposed or in the outer peripheral surfaces 12A and 12B of the expanded diameter section 12, can be calculated. Thermal strain is the product of temperature change and the coefficient of linear expansion. By correcting the strain detected by the strain sensor 31 based on the thermal strain, the strain generated by cutting can be more accurately determined.

[0082] Next, the arrangement of the housing 21 relative to the shaft portion 10 will be described. (Refer to...) Figure 8 as well as Figures 13-16 The housing 21 includes a housing body 61, a first fixing member 63, a second fixing member 65, and a cover 22. For example... Figure 13 As shown, the housing body 61 includes: a disc-shaped bottom wall portion 24 having a through hole 61A in the center; and a side wall portion 23 that rises from the outer peripheral surface of the bottom wall portion 24 and has a cylindrical shape. In the bottom wall portion 24, a plurality of threaded holes 62 are formed at equal intervals along the circumference (eight in this case), penetrating the bottom wall portion 24 in the thickness direction. The material constituting the housing body 61 is, for example, a metal. Examples of usable metals include aluminum alloys and ferrous alloys (such as stainless steel).

[0083] Reference Figure 14 The first fixing member 63 has a shape that is divided into two annular plates. On the first fixing member 63, a plurality of threaded holes 64 are formed at equal intervals along the circumference, corresponding to the threaded holes 62 of the bottom wall portion 24 of the housing body 61 (here, a total of eight in the two first fixing members 63). The inner circumferential surface 63A of the first fixing member 63 has a shape corresponding to the first small diameter portion 11A of the shaft portion 10. When the two first fixing members 63 are combined to form an annulus, the diameter of the inner circumferential surface 63A is the same as or slightly larger than the diameter of the first small diameter portion 11A. The material constituting the first fixing member 63 is, for example, metal. Examples of usable metals include aluminum alloys and iron alloys (such as stainless steel).

[0084] Reference Figure 15The second fixing member 65 is a component with a flat, arc-shaped plate. In this embodiment, the housing 21 includes two second fixing members 65. The inner peripheral surface 65A of each second fixing member 65 has a shape corresponding to a portion of the planar shape of the outer peripheral surface of the enlarged diameter portion 12, that is, a shape corresponding to a portion of an octagon. Multiple threaded holes 66 are formed on the second fixing member 65, corresponding to the threaded holes 62 in the bottom wall portion 24 of the housing body 61 and the threaded holes 64 in the first fixing member 63 (here, two are formed for each second fixing member 65). The material constituting the second fixing member 65 is, for example, resin.

[0085] Reference Figure 16 The cover (upper wall) 22 has a disc-shaped form with a through hole 22A in the center. The material constituting the cover 22 is, for example, resin.

[0086] The housing 21 can be disposed on the shaft portion 10 with the strain sensor component 30 and the base plate module 40 installed. (See reference...) Figure 8 The housing body 61 is configured such that the main body 11 of the shaft portion 10 passes through the through hole 61A of the bottom wall portion 24 of the housing body 61. The first fixing member 63, when disposed on the bottom wall portion 24, is embedded in the first small diameter portion 11A such that its inner circumferential surface 63A contacts the bottom wall of the first small diameter portion 11A of the main body portion 11. The second fixing member 65, when disposed on the first fixing member 63, is configured such that its inner circumferential surface 65A contacts the outer circumferential surfaces 12A and 12B of the enlarged diameter portion 12. Furthermore, the housing body 61, the first fixing member 63, and the second fixing member 65 are fixed together by screws passing through the threaded hole 66 of the second fixing member 65, the threaded hole 64 of the first fixing member 63, and reaching the threaded hole 62 of the bottom wall portion 24. At this time, since the inner diameter of the first fixing member 63 corresponds to the outer diameter of the first small diameter portion 11A, the central axis of the housing body 61 is aligned with the rotation axis A. Furthermore, since the inner circumferential surface 65A of the second fixing member 65 has a shape corresponding to a portion of the planar shape of the outer circumferential surface of the expanded diameter portion 12 (a shape corresponding to a portion of an octagon), it prevents the housing body 61 from rotating relative to the shaft portion 10 in the circumferential direction. The cover (upper wall portion) 22, while mounted on the end face of the side wall portion 23 and the end face of the expanded diameter portion 12, is fixed to the expanded diameter portion 12, for example, by screws. Thus, the housing 21 is fixed to the shaft portion 10 while housing the sensor module 80 inside.

[0087] (The movement of the cutting tool)

[0088] When the cutting tool 1 is in operation, it rotates around the rotation axis A. Furthermore, the workpiece is machined by bringing the cutting insert 91 into contact with it. During this time, the strain and acceleration of the shaft portion 10 are detected by the strain sensor 31 and the acceleration sensor 52, respectively. The strain and acceleration information, which are analog signals, are converted into digital signals in the AD converter 54 and then transmitted to the outside via the wireless communication unit 51. Since the cover (upper wall) 22 of the housing 21 is made of resin, the wireless communication unit 51 can transmit signals to the outside through the cover (upper wall) 22. This signal is received and analyzed externally, thereby allowing the state of the shaft portion 10 in the plane perpendicular to the rotation axis to be determined.

[0089] (Effects of this implementation method)

[0090] In the cutting tool 1 of this embodiment, the area of ​​the shaft portion 10 surrounded by the sensor portion 20 includes an enlarged diameter portion 12 that is octagonal when viewed along the direction of the rotation axis A. Furthermore, a plurality of strain sensors 31 for detecting strain are arranged on each of the outer peripheral surfaces 12A and 12B of the enlarged diameter portion 12, corresponding to each side of the octagon, along a perpendicular line L passing through the rotation axis A. B The strain is detected on the outer peripheral surface 12B of the expanded diameter portion 12, which is at a 90° angle to each other. Therefore, the sensor for detecting strain is configured to have a 90° phase difference during rotation about the rotation axis A. As a result, the strain in the plane perpendicular to the rotation axis A can be properly measured. This measured strain is useful for monitoring the state of the cutting tool 1 during machining. As described above, the cutting tool 1 of this embodiment is a cutting tool capable of acquiring more useful data through the sensor.

[0091] Furthermore, in this embodiment, when viewed along the direction of rotation axis A, among the outer peripheral surfaces 12A and 12B of the expanded diameter portion corresponding to the circumferentially adjacent sides of the aforementioned octagon, the perpendicular line L passing through rotation axis A of outer peripheral surface 12A... A The perpendicular line L passing through the rotation axis A to the outer peripheral surface 12B B The angles formed by them are equal. As a result, the symmetry of the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12 where the strain sensor 31 is installed relative to the rotation axis A becomes higher.

[0092] Furthermore, in this embodiment, the substrate 49 is configured such that, when viewed along the direction of the rotation axis A, it extends along the outer peripheral surfaces 12A and 12B of the expanded diameter portion 12. This makes it less likely for the substrate module 40 to move relative to the shaft portion 10. As a result, the accuracy of the information obtained from the strain sensor 31 is improved.

[0093] Furthermore, in this embodiment, a first recess 16 is formed on the outer peripheral surface 12B of the enlarged diameter portion 12. The strain sensor 31 is housed within the first recess 16. This simplifies the installation of the strain sensor 31.

[0094] Furthermore, in this embodiment, a second recess 15 is formed on the outer peripheral surfaces 12A and 12B of the enlarged diameter portion 12. The strain sensor 31 is configured to span the second recess 15. As a result, strain can be measured easily and with high accuracy.

[0095] Furthermore, in this embodiment, the second recess 15 is deeper than the first recess 16 and overlaps with the first recess 16. This facilitates the installation of the strain sensor 31 and allows for high-precision measurement of strain using the strain sensor 31.

[0096] Furthermore, in this embodiment, the second recess 15 is a groove extending circumferentially along the enlarged diameter portion 12. The first recess extends in a direction orthogonal to the second recess. This makes it easier to install the strain sensor 31 and to measure strain with high accuracy using the strain sensor 31.

[0097] Furthermore, in this embodiment, the sensor module 80 includes multiple acceleration sensors 52 for detecting the acceleration of the shaft. This allows for the simultaneous measurement of both strain and acceleration.

[0098] In this embodiment, the strain sensor 31 and the acceleration sensor 52 are disposed on the outer peripheral surfaces 12A and 12B of the enlarged diameter portion 12, which correspond to the different sides of the octagon described above. While the strain sensor 31 and the acceleration sensor 52 could also be disposed on the same outer peripheral surfaces 12A and 12B, disposing of them on different surfaces simplifies sensor placement.

[0099] Furthermore, in this embodiment, the wiring 32 constituting the strain sensor component 30 connects the strain sensor and the socket 53 in a sag manner. Therefore, the strain sensor 31 can be easily installed without adjusting the length of the wiring 32.

[0100] Furthermore, in this embodiment, the substrate 49 bends in a bendable region 49A, which is thinner than the first region 41 where the wireless communication unit 51 is mounted and the fifth region 45 where the AD converter 54 is mounted. This prevents the relatively large components, such as the wireless communication unit 51 and the AD converter 54, from peeling off due to deformation of the substrate 49, and makes deformation of the substrate used for installation easier.

[0101] Furthermore, in this embodiment, the substrate 49 is a rigid substrate. A groove is formed in the bendable region 49A of the substrate 49 to connect the two ends along the direction of the rotation axis A. As a result, the bendable region 49A can be easily formed.

[0102] (Example of substrate deformation)

[0103] Instead of the rigid substrate 49 described in the above embodiment, a modified substrate 49 as shown below may also be used. (Refer to...) Figure 17 as well as Figure 18 In this modified example, the substrate 49 includes: a main body portion 49B, which is a flexible substrate; and a reinforcing plate 72, which is disposed at least in a first region 41, which is a second region, and a fifth region 45, which is a third region, and the Young's modulus of the reinforcing plate 72 is greater than that of the main body portion 49B. In this modified example, the reinforcing plate 72 is disposed in the first region 41, the third region 43, the fifth region 45, and the seventh region 47. Thus, by using the main body portion 49B as a flexible substrate and forming a structure in which only the necessary parts are reinforced by the reinforcing plate 72, the same effect as in the above-described embodiment can be obtained.

[0104] (Other variations)

[0105] In the above embodiments, the case where strain sensor 31 and acceleration sensor 52 are used as the first sensor and the second sensor, respectively, has been described. However, for example, acceleration sensor 52, as the second sensor, may be omitted. Alternatively, strain sensor 31 may be omitted, and only acceleration sensor 52 may be used. That is, the first sensor may also be an acceleration sensor. Furthermore, one or both of strain sensor 31 and acceleration sensor 52 may be used instead, and sensors that detect physical quantities other than strain and acceleration may also be used in addition to them.

[0106] In the above embodiments, an end mill was described as an example of a cutting tool of this disclosure, but the cutting tools of this disclosure are not limited to this. The cutting tools of this disclosure may include, for example, drills, end mills, boring tools, reamers, taps, etc.

[0107] In the above embodiment, the case where the expanded diameter portion 12 of the region surrounded by the sensor portion 20 and disposed on the shaft portion 10 is octagonal when viewed along the direction of the rotation axis A has been described. However, the planar shape of the expanded diameter portion can be any 4n-sided polygon (n is a natural number of 2 or more), for example, it can also be a dodecagon, hexagon, or icosagon.

[0108] In the above embodiment, the strain sensor 31 was described as being disposed on all (four) of the outer peripheral surfaces 12B of the expanded diameter portion 12, which are each of the outer peripheral surfaces 12A and 12B corresponding to the sides of the octagon and are perpendicular to each other through the rotation axis A. However, the strain sensor only needs to be disposed on at least two surfaces. To describe it more generally, the first outer peripheral surface and the second outer peripheral surface, which are perpendicular to each other through the rotation axis in relation to the first outer peripheral surface, are considered as a group of three outer peripheral surfaces: either the first outer peripheral surface and the third outer peripheral surface, which are perpendicular to the rotation axis in relation to the first outer peripheral surface, are 90° to each other, or the third outer peripheral surface, which is 180° to the first outer peripheral surface in relation to the rotation axis, are considered as a group of three outer peripheral surfaces. The strain sensor is disposed on each of the outer peripheral surfaces in this group of outer peripheral surfaces. By placing strain sensors on the first and second outer peripheral surfaces, which are perpendicular to the axis of rotation and at 90° angles to each other, information related to the magnitude and direction of the load acting in a plane perpendicular to the axis of rotation can be obtained. Furthermore, by also placing a strain sensor on the third outer peripheral surface, the influence of loads parallel to the axis of rotation can be eliminated, resulting in more accurate information regarding the magnitude and direction of the load acting in a plane perpendicular to the axis of rotation. Multiple sets of the aforementioned set of outer peripheral surfaces can also exist. For example, if two sets of the aforementioned set of outer peripheral surfaces exist, strain sensors can be placed on each set of outer peripheral surfaces containing two or three outer peripheral surfaces. That is, strain sensors can be placed on a maximum of six outer peripheral surfaces. There is no angle limitation between the sets of outer peripheral surfaces in two groups.

[0109] In the above embodiments, the case where the first fixing member 63 and the second fixing member 65 are separate components has been described. However, the first fixing member 63 and the second fixing member 65 may also be integral. In this case, the first fixing member 63 and the second fixing member 65 may also be integral metal components.

[0110] (Other implementation methods)

[0111] Next, another embodiment of this disclosure will be described. Figure 19 This is a schematic perspective view showing the structure of the cutting tool in another embodiment. (Refer to...) Figure 19 The cutting tool 1 in this embodiment basically has the same characteristics as that based on Figures 1 to 18 The cutting tool 1 of the above-described embodiments has the same structure, operates in the same manner, and achieves the same effect. However, the cutting tool 1 of this embodiment differs from that of the above-described embodiments mainly in the structure of the shaft portion 10.

[0112] Specifically, refer to Figure 19In this embodiment, the shaft portion 10 includes a first annular protrusion 10D and a second protrusion 10E that project radially (in a direction perpendicular to the rotation axis A) in the region closer to the second end portion 10B than the sensor portion 20. When viewed from the first protrusion 10D, the second protrusion 10E is disposed on the second end portion 10B side. In the direction along the rotation axis A, the region between the first protrusion 10D and the second protrusion 10E of the shaft portion 10 is formed as a groove 10G. When viewed from the second protrusion 10E, the region on the side opposite to the first protrusion 10D is formed as a tapered portion 10F whose diameter decreases as it approaches the second end portion. That is, the shaft portion 10 of this embodiment includes a tapered portion 10F having a frustum-shaped form.

[0113] In the operating state of the cutting tool 1 in this embodiment, the cutting tool 1 is held on the machine tool spindle by inserting the tapered portion 10F into the recess formed in the machine tool spindle. The shapes of the tapered portion 10F, the first protrusion 10D, and the second protrusion 10E can be appropriately selected according to the tool holding mechanism provided by the machine tool spindle.

[0114] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not restrictive in any way. The scope of the invention is defined not by the foregoing description but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0115] Explanation of reference numerals in the attached figures

[0116] 1: Cutting tool; 10: Shaft portion; 10A: First end portion; 10B: Second end portion; 10C: Through hole; 10D: First protrusion; 10E: Second protrusion; 10F: Tapered portion; 11: Main body portion; 11A: First small diameter portion; 11B: Second small diameter portion; 12: Expanded diameter portion; 12A: Outer peripheral surface; 12B: Outer peripheral surface; 13: Recess; 15: Second recess; 16: First recess; 16A: Bottom surface; 20: Sensor portion; 21: Housing; 22: Cover; 22A: Through hole; 23: Side wall portion; 24: Bottom wall portion; 30: Sensor component; 31: Strain sensor; 32: Wiring; 33: Connector; 40: Substrate module ; 41: First zone; 42: Second zone; 43: Third zone; 44: Fourth zone; 45: Fifth zone; 46: Sixth zone; 47: Seventh zone; 48: Eighth zone; 49: Substrate; 49A: Bendable area; 49B: Main body; 51: Wireless communication unit; 52: Accelerometer; 53: Socket; 54: AD converter; 61: Housing body; 61A: Through hole; 62: Threaded hole; 63: First fixing member; 63A: Inner circumferential surface; 64: Threaded hole; 65: Second fixing member; 65A: Inner circumferential surface; 66: Threaded hole; 72: Reinforcing plate; 80: Sensor module; 91: Cutting blade; 92: Screw; A: Rotating shaft; L A L B : Vertical line; θ: Angle; d1, d2: Depth; a, b: Measurement range.

Claims

1. A cutting tool comprising: a shaft portion extending from a first end portion to a second end portion along a rotation axis; and a sensor portion configured to surround a part of a length direction of the shaft portion, the cutting tool performing cutting of a workpiece by rotating around the rotation axis of the shaft portion, wherein the sensor portion includes: a sensor module including a plurality of first sensors that detect a first physical quantity of the shaft portion, a substrate electrically connected to the first sensors, and a wireless communication portion electrically connected to the substrate and externally transmitting a signal including information of the first physical quantity detected by the first sensors; and a housing that houses the sensor module, a region of the shaft portion surrounded by the sensor portion includes a first region that is a 4n-sided polygon when viewed in a direction along the rotation axis, n is a natural number of 2 or more, when viewed in the direction along the rotation axis, the plurality of first sensors are disposed on at least two faces of the outer peripheral surface of the first region that are 90° apart from each other by a perpendicular line to the rotation axis among each of the faces of the outer peripheral surface of the first region corresponding to each side of the 4n-sided polygon, when viewed in the direction along the rotation axis, the substrate is disposed to follow the outer peripheral surface of the first region along the outer peripheral surface of the first region corresponding to a plurality of sides of the 4n-sided polygon. when viewed in the direction along the rotation axis, angles formed by perpendicular lines to the rotation axis of each of the faces of the outer peripheral surface of the first region corresponding to circumferentially adjacent sides of the 4n-sided polygon are equal.

2. The cutting tool of claim 1, wherein, 3. The cutting tool according to claim 1, wherein a first recess is formed in an outer peripheral surface of the shaft portion, the first sensor is housed in the first recess.

4. The cutting tool according to any one of claims 1 to 3, wherein the first sensor is a strain sensor.

5. The cutting tool according to claim 4, wherein a second recess is formed in the outer peripheral surface of the shaft portion, the first sensor is disposed to straddle the second recess.

6. The cutting tool according to claim 1, wherein the first sensor is a strain sensor, a first recess and a second recess deeper than the first recess and overlapping the first recess are formed in the outer peripheral surface of the shaft portion, the first sensor is disposed to straddle the second recess and is housed in the first recess.

7. The cutting tool according to claim 6, wherein the second recess is a groove extending in a circumferential direction of the shaft portion, the first recess extends in a direction orthogonal to the second recess.

8. The cutting tool according to any one of claims 1 to 3, wherein the first sensor is an acceleration sensor.

9. The cutting tool according to any one of claims 1 to 3, wherein the sensor module further includes a plurality of second sensors that detect a second physical quantity of the shaft portion different from the first physical quantity, the substrate is electrically connected to the second sensors, the wireless communication portion is electrically connected to the substrate and externally transmits a signal including information of the second physical quantity detected by the second sensors. ​ 10. The cutting tool according to claim 9, wherein the first sensor is a strain sensor that detects strain as the first physical quantity, the second sensor is an acceleration sensor that detects acceleration as the second physical quantity.

11. The cutting tool according to claim 9, wherein the first sensor and the second sensor are disposed on the outer peripheral surface of the first region corresponding to different sides of the 4n-sided polygon.

12. The cutting tool according to any one of claims 1 to 3, wherein the sensor module further includes a wiring connected to the first sensor, the wiring connects the first sensor to the substrate in a manner having a sag.

13. The cutting tool according to any one of claims 1 to 3, wherein the sensor module further includes an AD converter disposed on the substrate, the substrate has a smaller thickness in a fourth region other than a second region in which the wireless communication section is mounted and a third region in which the AD converter is mounted than in the second region and the third region, and the substrate is bent in the fourth region.

14. The cutting tool according to claim 13, wherein the substrate is a rigid substrate, a groove connecting both ends in a direction along the rotation axis is formed in the fourth region of the substrate.

15. The cutting tool according to claim 13, wherein the substrate includes: a main body portion that is a flexible substrate; and a reinforcing plate disposed on the second region and the third region, and the reinforcing plate has a larger Young's modulus than the Young's modulus of the main body portion. ​

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