Tool holder attachment

Abstract

The tool holder attachment comprises an attachment body that connects a tool mounting portion included in a machine tool and a tool holder, and a sensor portion that is attached to the attachment body and has at least one sensor element that detects a physical quantity of the attachment body.

Description

[Technical field]

[0001] The present disclosure relates to a tool holder attachment. [Background technology]

[0002] When machining a workpiece using a machine tool, there is known a technique for grasping the state of a cutting tool by measuring the physical quantity of the cutting tool using a sensor (for example, U.S. Patent Application Publication No. 2015 / 0261207 (Patent Document 1), Japanese Patent Application Laid-Open No. 2018-54611 (Patent Document 2), Japanese Patent Application Laid-Open No. 2009-285804 (Patent Document 3), International Publication No. 2017 / 002762 (Patent Document 4), See Japanese Patent No. 5988066 (Patent Document 5), Utility Model Registration No. 3170029 (Patent Document 6), JP 2015-77658 A (Patent Document 7), WO 2015 / 056495 A (Patent Document 8), European Patent Application Publication No. 3292929 A (Patent Document 9), European Patent Application Publication No. 3292930 A (Patent Document 10), and U.S. Patent Application Publication No. 2009 / 0235763 A (Patent Document 11)). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2015 / 0261207 [Patent Document 2] JP 2018-54611 A [Patent Document 3] JP 2009-285804 A [Patent Document 4] International Publication No. 2017 / 002762 [Patent Document 5] JP 2016-221665 A [Patent Document 6] Utility model registration No. 3170029 [Patent Document 7] JP 2015-77658 A [Patent Document 8] International Publication No. 2015 / 056495 [Patent Document 9] European Patent Application Publication No. 3292929 [Patent Document 10] European Patent Application Publication No. 3292930 [Patent Document 11] US Patent Application Publication No. 2009 / 0235763 Summary of the Invention

[0004] A tool holder attachment according to the present disclosure comprises an attachment body that connects a tool holder to a tool mounting portion included in a machine tool, and a sensor portion attached to the attachment body and having at least one sensor element that detects a physical quantity of the attachment body. [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic front view showing a state in which an attachment and a tool holder are mounted on a tool mounting portion of a machine tool in an embodiment. [Diagram 2] FIG. 2 is a schematic perspective view of the attachment according to the embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along the line BB in FIG. [Figure 4] FIG. 4 is a schematic plan view of the attachment according to the embodiment as viewed in a second direction. [Diagram 5] FIG. 5 is a schematic bottom view of the attachment according to the embodiment as viewed in a first direction. [Figure 6] FIG. 6 is a schematic cross-sectional view taken along line CC in FIG. [Figure 7] FIG. 7 is a schematic perspective view of an attachment according to a modified example. [Figure 8] FIG. 8 is a schematic cross-sectional view taken along a line DD in FIG. [Figure 9] FIG. 9 is an enlarged view of part A in FIG. [Figure 10]FIG. 10 is a schematic bottom view of an attachment according to a modified example, as viewed in a first direction. [Figure 11] FIG. 11 is a schematic cross-sectional view of the attachment with the case attached, taken along a cross-section including line DD in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] [Problem that this disclosure aims to solve] When attempting to grasp the state of a cutting tool using a tool holder equipped with a sensor unit, the following problem occurs. Since it is necessary to select the type of tool holder to be used depending on the processing mode of a molded product, it is necessary to attach a sensor unit to each of the many types of tool holders. For example, when performing high-load cutting, it is necessary to use a milling chuck with high gripping force as the tool holder. For example, when performing high-precision cutting, it is necessary to use a hydrochuck or a shrink-fit holder as the tool holder.

[0007] Therefore, when a tool holder having sensor units attached thereto is used, there is a problem that the number of sensor units increases. Therefore, it is an object of the present disclosure to provide a tool holder attachment that can reduce the number of sensor units when attempting to grasp the state of a cutting tool using the sensor units when forming a molded product by cutting. Hereinafter, the tool holder attachment will be referred to as an "attachment."

[0008] [Effects of this disclosure] According to the attachment of the present disclosure, in the case where the state of a cutting tool is grasped by the sensor parts when a molded product is formed by cutting, the number of sensor parts can be reduced.

[0009] [Description of the embodiments of the present disclosure] First, the embodiments according to the present disclosure will be listed and described. The attachment according to the present disclosure includes an attachment body that connects a tool mounting part and a tool holder included in a machine tool, and a sensor unit that is attached to the attachment body and has at least one sensor element that detects a physical quantity of the attachment body.

[0010] In the attachment according to the present disclosure, a sensor unit is attached to the attachment body. Using this attachment, one tool holder selected from many types of tool holders as necessary is attached to the tool attachment part. As a result, even when many types of tool holders are used, the state of the cutting tool is grasped by the sensor unit attached to the attachment. As a result, when the state of the cutting tool is grasped by the sensor unit when forming a molded product by cutting processing, the number of sensor units can be reduced. As a result, not only can the initial cost required for introducing the sensor unit be reduced, but the maintenance work for the sensor unit can also be reduced, thereby reducing running costs. The state of the cutting tool means the current state of the cutting tool based on an evaluation based on physical quantities generated in the cutting tool (for example, wear, fatigue, breakage, peeling, plastic deformation, cracking). By grasping the state of the cutting tool, for example, it is possible to grasp the time to replace the cutting tool and predict abnormalities in the cutting tool.

[0011] In the attachment, the sensor unit may further include a wireless communication unit that transmits a signal generated in response to detection by the sensor element to the outside. With this configuration, a signal including information on the physical quantity of the attachment body is instantly transmitted to the outside by the wireless communication unit, making it possible to perform real-time processing.

[0012] In the attachment, the sensor section may further include a power supply section that supplies power to the sensor element. With this configuration, power can be supplied to the sensor element from the power supply section that is attached to the attachment body.

[0013] The attachment may further include a case for housing the at least one sensor element. With this configuration, the sensor element is more likely to be protected from foreign matter such as cutting chips.

[0014] The attachment may further include a seal portion that surrounds the at least one sensor element between an outer circumferential surface of the attachment body and the case. This configuration can reduce the amount of foreign matter, such as liquid and fine chips, that enters the case.

[0015] In the attachment, the attachment body may have a base, a shank, and a grip. The shank protrudes from the base along a first direction from the tool holder toward the tool mounting part, and is attached to the tool mounting part. The grip protrudes from the base along a second direction from the tool mounting part toward the tool holder, and includes an insertion hole into which the shank of the tool holder is inserted. The outer peripheral surface of the shank may include a tapered surface that approaches a central axis as it progresses in the first direction. With this configuration, when the attachment is mounted to the tool mounting part, the tapered surface of the shank is likely to come into close contact with the inner peripheral surface of the tool mounting part, and the binding force of the attachment to the tool mounting part is likely to increase. In addition, it is possible to reduce the deviation of the central axis of the attachment from the central axis of the tool mounting part.

[0016] In the attachment, the attachment body may have a base, a shank, and a grip. The shank protrudes from the base along a first direction from the tool holder toward the tool mounting part, and is attached to the tool mounting part. The grip protrudes from the base along a second direction from the tool mounting part toward the tool holder, and includes an insertion hole into which the shank of the tool holder is inserted. An inner circumferential surface surrounding the insertion hole may include a tapered surface that approaches a central axis as it progresses in the first direction. With this configuration, when the tool holder is attached to the attachment, the outer circumferential surface of the shank in the tool holder is likely to come into close contact with the inner circumferential surface of the attachment, and the binding force of the tool holder with respect to the attachment is likely to increase. In addition, the deviation of the central axis of the tool holder from the central axis of the attachment can be reduced.

[0017] In the attachment, a virtual plane perpendicular to the second direction and intersecting the at least one sensor element may intersect the insertion hole. With this configuration, the sensor element can be disposed in a portion of the attachment close to the tool holder, making it easy to grasp a state of the cutting tool.

[0018] In the attachment, the at least one sensor element may include a detection area that is an area for detecting the physical quantity, and the imaginary plane that intersects the detection area may intersect the insertion hole. With this configuration, the detection area of ​​the sensor element is disposed at a position close to the insertion hole, making it easier to detect the physical quantity of the attachment body.

[0019] In the attachment, a recess may be formed in the outer peripheral surface of the attachment body, in which at least a portion of the at least one sensor element is disposed. With this configuration, it is easy to specify a position where the sensor element should be disposed with respect to the outer peripheral surface of the attachment body.

[0020] In the attachment, the sensor unit may further include a substrate and wiring electrically connecting the substrate and the at least one sensor element. The at least one sensor element may be disposed in a region of the substrate that is located in a second direction from the tool attachment portion toward the tool holder. With this configuration, the sensor element is disposed in a portion of the attachment body that is close to the tool holder, making it easy to grasp the state of the cutting tool.

[0021] In the attachment, the gripping portion may have a placement portion in which the at least one sensor element is placed and recessed from an outer peripheral surface of the gripping portion. The thickness between the outer peripheral surface included in the gripping portion and an inner peripheral surface surrounding the insertion hole may be configured to change in a third direction along an intersection line between the imaginary plane and the inner surface. The placement portion may be formed at a position shifted in the third direction with respect to a portion of the outer peripheral surface included in the gripping portion that corresponds to the minimum value of the thickness. With this configuration, it is possible to specify the position where the sensor element should be placed, while reducing a decrease in rigidity of the attachment body due to the formation of the placement portion.

[0022] In the attachment, the at least one sensor element may include a force sensor element. With this configuration, it is possible to grasp the strain generated in the attachment body.

[0023] In the attachment, the at least one sensor element may include an acceleration sensor element or an AE (Acoustic Emission) sensor element. With this configuration, the acceleration sensor element or the AE sensor element is disposed in a location close to the insertion hole, making it easier to detect vibrations occurring in the attachment.

[0024] In the attachment, the at least one sensor element may include a temperature sensor element. With this configuration, the temperature sensor element is disposed near the insertion hole, so that the temperature sensor element can be easily disposed at a position away from the cooling passage through which the cooling water passes. As a result, the temperature sensor element is less affected by the cooling water and can appropriately detect the heat conducted from the tool holder.

[0025] In the attachment, the attachment body may have a slit formed in an outer peripheral surface of the attachment body along an intersection line between the outer surface and the imaginary plane. The at least one sensor element may include a force sensor element attached so as to straddle the slit. With this configuration, strain generated in the portion where the force sensor element is attached is locally amplified, making it easy to increase sensitivity to strain caused by the force sensor element.

[0026] In the attachment, an outer circumferential surface of the shank portion and an inner circumferential surface surrounding the insertion hole may have the same shape. With this configuration, an extension can be used as the attachment.

[0027] In the attachment, an inner circumferential surface of the shank portion and an inner circumferential surface surrounding the insertion hole may have different shapes. With this configuration, an adapter can be used as the attachment.

[0028] [Details of the embodiment of the present disclosure] Next, an embodiment of the attachment 10 according to the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated.

[0029] FIG. 1 is a schematic front view showing an example of a state in which an attachment 10 and a tool holder 4 according to the present embodiment are attached to a machine tool. Referring to FIG. 1, the attachment 10 according to the present embodiment is attached between a tool attachment portion 6 of the machine tool and the tool holder 4. The machine tool forms a molded product by performing cutting processing on a workpiece. Examples of the machine tool include machine tools that mainly perform turning processing, such as a machining center and a milling machine (a general-purpose milling machine, an NC (Numerical Control) milling machine, etc.), and machine tools that mainly perform turning processing, such as a lathe (a general-purpose lathe, an NC lathe). In the present embodiment, a machine tool that mainly performs turning processing will be described as an example of the machine tool.

[0030] 1, in the present disclosure, the direction from the tool holder 4 to the tool mounting part 6 is defined as a "first direction D1." The direction from the tool mounting part 6 to the tool holder 4 is defined as a "second direction D2." The tool mounting part 6 in this embodiment is a main shaft (spindle). Therefore, in this embodiment, both the first direction D1 and the second direction D2 are aligned along the rotation axis R1 of the tool holder 4 and the tool mounting part 6 (main shaft).

[0031] Of the two opposite directions along the arc centered on the rotation axis R1, the clockwise (right-handed) direction as viewed in the second direction D2 is defined as the "third direction R3," and the counterclockwise (left-handed) direction is defined as the "fourth direction R4." The descriptions "first direction D1," "second direction D2," "third direction R3," and "fourth direction R4" are merely labels for distinguishing the directions and do not imply any order of priority.

[0032] In this disclosure, "parallel" includes not only cases where two lines, sides, faces, etc. do not intersect when extended, but also cases where the angle between them is within 3 degrees when they intersect. "Perpendicular" includes not only cases where two lines, sides, faces, etc. intersect at 90 degrees when extended, but also cases where they intersect within a range of 90 degrees ±3 degrees.

[0033] 1, the machine tool has a tool mounting portion 6 to which an attachment 10 can be attached. Not only the attachment 10 but also the tool holder 4 can be directly attached to the tool mounting portion 6. The tool mounting portion 6 includes an opening (hereinafter referred to as an insertion opening 61). Either the shank portion 12 of the attachment 10 or the shank 41 of the tool holder 4 can be inserted into the insertion opening 61.

[0034] A cutting tool 5 is attached to the tool holder 4. In this embodiment, a milling tool is used as the cutting tool 5. Examples of the milling tool include an end mill, a drill, a milling cutter, a boring tool, a reamer, and a tap.

[0035] (Outline of the structure of Attachment 10) Fig. 2 is a schematic perspective view showing the structure of the attachment 10 according to the present embodiment. Fig. 3 is a schematic cross-sectional view taken along a cross section including line BB in Fig. 2 and intersecting with the sensor element 31. Case 7 is omitted in Figs. 2 and 3. With reference to Figs. 2 and 3, the attachment 10 according to the present embodiment includes an attachment main body 1, a fixing screw 2 attached within the attachment main body 1, a sensor unit 3 attached to the outer circumferential surface of the attachment main body 1, and a case 7. With reference to Fig. 1, the attachment 10 is disposed between the tool attachment portion 6 and the tool holder 4, thereby connecting the tool attachment portion 6 and the tool holder 4.

[0036] Examples of the attachment 10 include an extension and an adapter. The extension is disposed between the tool mounting portion 6 and the tool holder 4, and can extend the distance between the tool mounting portion 6 and the tool holder 4 compared to when the tool holder 4 is directly attached to the tool mounting portion 6. In the extension, the outer peripheral surface of the portion (shank portion 12) inserted into the tool mounting portion 6 and the gripping portion inner peripheral surface 141 surrounding the insertion hole 15 into which the shank 41 of the tool holder 4 is inserted have the same shape. The adapter is disposed between the tool mounting portion 6 and the tool holder 4 having the shank 41 that cannot be directly attached to the tool mounting portion 6, and can attach the tool holder 4 to the tool mounting portion 6. In the adapter, the outer peripheral surface of the portion (shank portion) inserted into the tool mounting portion 6 and the gripping portion inner peripheral surface 141 surrounding the insertion hole 15 into which the shank 41 of the tool holder 4 is inserted have different shapes. The "different shapes" mentioned here also includes similar shapes. That is, the adapter also includes a reduction adapter. In this embodiment, an extension will be taken as an example of the attachment 10 for explanation.

[0037] In this disclosure, "same" includes cases where the objects to be compared are considered to be the same, and is not "same" in the strict sense. In this disclosure, "different" means that the objects to be compared are other than the same.

[0038] (Structure of attachment body 1) The attachment body 1 connects the tool mounting portion 6 and the tool holder 4. With reference to Fig. 3, the attachment body 1 includes a base portion 11, a shank portion 12 protruding from the base portion 11 in a first direction D1, and a grip portion 13 protruding from the base portion 11 in a second direction D2. The shank portion 12, the base portion 11, and the grip portion 13 are arranged in this order along the second direction D2. Examples of materials for the attachment body 1 include metals. Examples of metals include aluminum alloys and iron alloys (steels such as stainless steel).

[0039] The base 11 is a portion that supports the shank portion 12 and the grip portion 13. The base 11 extends from a first end portion 114 to a second end portion 115 along the second direction D2. The base 11 is formed in a cylindrical shape. The central axis of the base 11 coincides with the rotation axis R1 of the main shaft. The outer diameter at the first end portion 114 and the outer diameter at the second end portion 115 are the same. The diameter of the outer peripheral surface of the base 11 (hereinafter, the base outer peripheral surface 111) is constant from the first end portion 114 to the second end portion 115.

[0040] The base outer peripheral surface 111 does not have to be formed in a cylindrical shape. The base outer peripheral surface 111 may be, for example, a polygon such as a square, a pentagon, or a hexagon when viewed in the second direction D2. The diameter of the base outer peripheral surface 111 does not have to be constant from the first end 114 to the second end 115, and may have a shape such as a constriction or a protrusion between the first end 114 and the second end 115.

[0041] Referring to FIG. 2, at least one groove 112 is formed on the base outer peripheral surface 111. The base 11 according to this embodiment includes a plurality of grooves 112. The plurality of grooves 112 are formed in a shape that allows a changer arm of an automatic tool changer (ATC; Automatic Tool Changer) to be hooked. After the changer arm is inserted into the groove 112, the changer arm moves in the first direction D1 or the second direction D2, whereby the attachment 10 is attached to and detached from the tool mounting portion 6. Each groove 112 is formed along the base outer peripheral surface 111 on a virtual plane perpendicular to the first direction D1 (second direction D2). That is, the groove 112 is formed along the intersection line between the virtual plane perpendicular to the first direction and the base outer peripheral surface 111. The plurality of grooves 112 according to this embodiment are formed intermittently at regular intervals on the base outer peripheral surface 111 along the third direction R3.

[0042] The base 11 may be configured to have only one groove 112. The one groove 112 may be formed on the base outer peripheral surface 111 over the entire length in the third direction R3, or may be continuous in the third direction R3 and only a part of the third direction R3 is interrupted. That is, the one groove 112 may be annular or C-shaped. The automatic tool changer may be a turret-type automatic tool changer, a magazine-type automatic tool changer, or a robot arm installed inside or outside the device.

[0043] The shank portion 12 is a portion that is attached to the tool attachment portion 6. Referring to FIG. 3, the shank portion 12 is formed in a cylindrical shape. Here, FIG. 4 is a schematic plan view of the attachment 10 viewed in the second direction D2. Referring to FIG. 4, the shank portion 12 according to this embodiment has a circular inner peripheral surface 122 and a non-circular outer peripheral surface 123 viewed in the second direction D2. The shank portion 12 has three protrusions 121 that protrude radially from a virtual circle K2 that is concentric with the inner peripheral surface 122 at 120 degree intervals. The diameter of the virtual circle K2 is larger than that of the inner peripheral surface 122. The tip surface of each of the protrusions 121 is a curved surface. The outer peripheral surface 123 is formed in a so-called Reuleaux triangle shape viewed in the second direction D2 because the shank portion 12 has three protrusions 121. The outer peripheral surface 123 according to this embodiment is formed in a three-fold rotationally symmetric shape viewed in the second direction D2.

[0044] The outer peripheral surface 123 of the shank portion 12 may include a surface parallel to the first direction D1, or may include a tapered surface that approaches the rotation axis R1 as it progresses in the first direction D1. In this embodiment, the outer peripheral surface 123 of the shank portion 12 is configured as a tapered surface that approaches the rotation axis R1 as it progresses in the first direction D1. Examples of the gradient of the tapered surface include a 7 / 24 taper and a 1 / 10 taper.

[0045] The maximum distance L1 between the end of the outer peripheral surface 123 of the shank portion 12 in the second direction D2 and the rotation axis R1 (the central axis of the attachment body 1) is shorter than the minimum distance L2 between the outer edge of the first end portion 114 of the base portion 11 and the rotation axis R1. Therefore, the first end portion 114 of the base portion 11 has a surface (hereinafter referred to as a flange surface 113) perpendicular to the rotation axis R1. When the attachment 10 is attached to the tool attachment portion 6, the flange surface 113 faces the tool attachment portion 6. At this time, the outer peripheral surface 123 of the shank portion 12 contacts the inner peripheral surface of the insertion opening 61, and the flange surface 113 contacts the end surface of the tool attachment portion 6 in the second direction D2. As a result, the attachment 10 is attached to the tool attachment portion 6 by two-surface constraint. The attachment of the attachment 10 to the tool mounting portion 6 may be restrained only by contact between the outer peripheral surface 123 of the shank portion 12 and the inner peripheral surface of the insertion opening 61, i.e., a gap may be present between the flange surface 113 and the tool mounting portion 6.

[0046] 3, the gripping portion 13 is a portion that holds the shank 41 of the tool holder 4. The gripping portion 13 has an outer peripheral wall 14 and an insertion hole 15 into which the shank 41 is inserted. The outer peripheral wall 14 protrudes in a second direction D2 from a second end portion 115 of the base portion 11. The outer peripheral wall 14 has an inner peripheral surface (hereinafter referred to as a gripping portion inner peripheral surface 141), an outer peripheral surface (hereinafter referred to as a gripping portion outer peripheral surface 142), and a contact surface 143. In the present disclosure, the terms "the outer peripheral surface of the attachment main body 1" and "the outer peripheral surface included in the attachment main body 1" refer to a surface constituted by the base outer peripheral surface 111 and the gripping portion outer peripheral surface 142, and do not include the outer peripheral surface 123 of the shank portion 12.

[0047] 5 is a schematic bottom view of the attachment 10 as viewed in the first direction D1. Referring to FIG. 5, when the insertion hole 15 is viewed in the first direction D1, the gripping inner circumferential surface 141 has a non-circular shape. When viewed in the first direction D1, the gripping inner circumferential surface 141 of the insertion hole 15 according to this embodiment has a so-called Reuleaux triangle shape. In other words, the shape of the gripping inner circumferential surface 141 surrounding the insertion hole 15 has a three-fold rotational symmetry shape when viewed in the first direction D1.

[0048] The grip inner peripheral surface 141 may include a surface parallel to the first direction D1, or may include a tapered surface that approaches the rotation axis R1 as it progresses in the second direction D2. In this embodiment, the grip inner peripheral surface 141 is configured as a tapered surface that approaches the rotation axis R1 as it progresses in the second direction D2. The gradient of the tapered surface may be, for example, a 7 / 24 taper or a 1 / 10 taper, similar to the outer peripheral surface 123 of the shank portion 12. In this embodiment, the grip inner peripheral surface 141 surrounding the insertion hole 15 is formed in the same shape as the outer peripheral surface of the shank portion 12.

[0049] 3, the gripper outer peripheral surface 142 is formed in a cylindrical shape. The diameter of the gripper outer peripheral surface 142 is the same as the outer diameter of the base 11. The contact surface 143 is a surface at the end of the gripper 13 in the second direction D2. The contact surface 143 is perpendicular to the second direction D2. When the shank 41 of the tool holder 4 is inserted into the insertion hole 15, the contact surface 143 contacts the flange surface of the tool holder 4. This allows the gripper 13 to hold the tool holder 4 by two-surface constraint by the gripper inner peripheral surface 141 and the contact surface 143 that form the insertion hole 15.

[0050] 5, the thickness of the outer peripheral wall 14 changes continuously along the third direction R3. The thickness of the outer peripheral wall 14 means the distance from the gripping portion inner peripheral surface 141 to the gripping portion outer peripheral surface 142 in the radial direction of the gripping portion outer peripheral surface 142 (hereinafter, sometimes referred to as the "radial direction"). When viewed in the first direction D1, the thickness L3 of a portion P1 of the outer peripheral wall 14 corresponding to the apex P2 of the insertion hole 15 is thinner than other portions. That is, the portion P1 of the outer peripheral wall 14 where the thickness is the minimum is the portion corresponding to the apex P2 of the insertion hole 15 when viewed in the first direction D1.

[0051] 3, the outer peripheral wall 14 has a placement portion 144 in which the sensor element 31 is placed. In the present embodiment, the placement portion 144 is recessed in the grip portion outer peripheral surface 142 relative to other portions. The recessed placement portion 144 makes it easy to identify the position where the sensor element 31 should be placed. However, the placement portion 144 does not have to be recessed in the grip portion outer peripheral surface 142 and may be formed, for example, by a printed mark.

[0052] 5, the arrangement portion 144 is offset in the third direction R3 with respect to a portion P1 of the grip portion outer peripheral surface 142 where the thickness of the outer peripheral wall 14 is at its minimum. In this case, it is preferable that the entire region of each arrangement portion 144 is away from the portion P1. This allows the sensor element 31 to be arranged at a position offset from the portion P1 in the grip portion 13 without being arranged at the thinnest portion P1. However, the arrangement portion 144 may be formed at a position overlapping the portion P1 on the grip portion outer peripheral surface 142. A portion of the plurality of arrangement portions 144 may be formed at a position overlapping the portion P1 on the grip portion outer peripheral surface 142.

[0053] The insertion hole 15 is a space into which the shank 41 is inserted. With reference to FIG. 3, the insertion hole 15 is formed by an end face (hereinafter, sometimes referred to as a hole bottom face 151) of the second end 115 of the base 11 and a gripping portion inner peripheral surface 141. The end face of the insertion hole 15 in the second direction D2 is an opening face. When the shank 41 of the tool holder 4 is inserted into the insertion hole 15 through the opening face, the hole bottom face 151 faces the end face of the shank 41 in the first direction D1. The hole bottom face 151 is formed with an insertion hole 152 for passing the fixing screw 2 through. The insertion hole 152 penetrates from the hole bottom face 151 to the end face of the shank portion 12 in the first direction D1.

[0054] 3, the base 11 has a position restricting portion 116 that rotatably holds the fixing screw 2. The position restricting portion 116 is formed on the inner circumferential surface of the insertion hole 152. The shape of the position restricting portion 116 in a cross section perpendicular to the first direction D1 is circular. The diameter of the position restricting portion 116 is larger than the diameter of the insertion hole 152. The position restricting portion 116 is formed in the base 11 between the second end portion 115 and the first end portion 114.

[0055] (Structure of Fixing Screw 2) The fixing screw 2 fixes the tool holder 4 to the attachment body 1. Referring to FIG. 3, the fixing screw 2 has a shaft portion 21 and a head portion 22. The outer shape of the head portion 22 is formed in a circular shape when viewed in the second direction D2. The outer diameter of the head portion 22 is larger than the outer diameter of the shaft portion 21. A swivel hole 221 is formed in the head portion 22. The swivel hole 221 is formed on the end surface of the head portion 22 in the first direction D1. The swivel hole 221 has a polygonal shape, such as a triangle, a rectangle, a pentagon, or a hexagon. The head portion 22 of the fixing screw 2 is accommodated in the position restricting portion 116, and the shaft portion 21 protrudes into the insertion hole 15 through the insertion hole 152. As a result, the fixing screw 2 is rotatably attached to the attachment body 1.

[0056] A thread 211 is formed on the shaft portion 21. The shank 41 is inserted into the insertion hole 15, and the fixing screw 2 is turned, whereby the shank 41 is fixed to the attachment body 1. In this way, the tool holder 4 can be attached to the attachment 10.

[0057] The attachment 10 has a cooling passage 16 formed along the central axis. The cooling passage 16 according to this embodiment penetrates from the tip surface of the shank portion 12, which is the tip surface in the first direction D1, through the base portion 11 and the fixing screw 2, to the tip surface of the fixing screw 2, which is the tip surface in the second direction D2. When the tool holder 4 is connected to the attachment 10, the cooling passage 16 communicates with a flow passage formed in the tool holder 4. This allows cooling water supplied from the machine tool to be supplied to the cutting edge of the cutting tool 5.

[0058] (Structure of sensor part 3) The sensor unit 3 has at least one sensor element 31 that detects a physical quantity of the attachment body 1. With reference to Fig. 2, the sensor unit 3 is attached to the attachment body 1. In the present embodiment, the sensor unit 3 is attached to the outer circumferential surface of the attachment body 1, but it may be disposed between the grip portion outer circumferential surface 142 and the grip portion inner circumferential surface 141 in the attachment body 1, or may be attached to the grip portion inner circumferential surface 141. The sensor unit 3 has at least one sensor element 31, as well as a plurality of substrates 32, a power supply unit 33, an AD converter 34, and a wireless communication unit 35.

[0059] Examples of the sensor element 31 include a force sensor element, a temperature sensor element, an acceleration sensor element, and an AE (Acoustic Emission) sensor element. When a plurality of sensor elements 31 are used, two or more types of sensor elements 31 are selected from a force sensor element, a temperature sensor element, an acceleration sensor element, and an AE sensor element. The acceleration sensor element detects acceleration as a physical quantity of the attachment body 1 and an elastic wave generated in the attachment body 1. The AE sensor element detects an elastic wave generated in the attachment body 1 as a physical quantity of the attachment body 1. The elastic wave can be generated by, for example, cracks, wear, vibration, and deformation in the attachment body 1. The force sensor element detects a force applied to the attachment body 1 as a physical quantity of the attachment body 1. The force sensor element can measure the strain generated in the attachment body 1. The force sensor element may be a strain sensor element or a piezoelectric stress sensor element. The temperature sensor element detects heat as a physical quantity of the attachment body 1.

[0060] 3, the sensor element 31 is attached to the grip portion outer peripheral surface 142 of the grip portion 13. An imaginary plane K1 that is perpendicular to the first direction D1 and intersects the sensor element 31 also intersects the insertion hole 15. In other words, the sensor elements 31 are arranged in a radial direction with respect to the insertion hole 15. A plurality of imaginary planes K1 that intersect the sensor element 31 are assumed, but in this embodiment, all of the imaginary planes K1 that intersect the sensor element 31 intersect the insertion hole 15. However, in the present disclosure, it is sufficient that at least one of the imaginary planes K1 that intersect the sensor element 31 intersects the insertion hole 15.

[0061] The sensor element 31 includes a detection area 312 and a connection portion 313 electrically connected to the detection area 312. In this embodiment, the detection area 312 in each sensor element 31 is disposed in the arrangement portion 144. The imaginary plane K1 intersecting the insertion hole 15 intersects with the detection area 312. The detection area 312 means an area in the sensor element 31 where the physical quantity of the attachment body 1 is input. For example, when the sensor element 31 is a strain sensor element, the detection area 312 is a grid portion in a metal foil resistor, and the connection portion 313 is a gauge lead. For example, when the sensor element 31 is a piezoelectric acceleration sensor element, the detection area 312 is a piezoelectric body, and the connection portion 313 is a lead wire. For example, when the sensor element 31 is a piezo-resistance acceleration sensor element, the detection area 312 is a piezo-resistance body, and the connection portion 313 is a lead wire.

[0062] With this configuration, when an acceleration sensor element is used as the sensor element 31, the sensor element 31 is disposed in a position in the attachment body 1 corresponding to a hollow portion having a smaller moment of area second than the thick portion (base portion 11). This allows the sensor element 31 to be disposed in a portion of the attachment body 1 where the amount of deflection is likely to be relatively large. Therefore, with this configuration, the acceleration sensor element can easily detect at least one of vibration and deflection occurring in the attachment 10.

[0063] When the gripping inner peripheral surface 141 surrounding the insertion hole 15 of the attachment 10 includes a tapered surface that approaches the rotation axis R1 as it advances in the first direction D1, the shank 41 of the tool holder 4 may be able to be inserted even if foreign matter such as cutting chips is attached to the opening periphery of the insertion hole 15. In this case, the position of the tip of the cutting tool 5 is shifted from the designed position, so that the precision of the molded product is impaired, and vibration due to rotation is likely to occur in the cutting tool 5 and the tool holder 4. However, by attaching at least one of an acceleration sensor element or an AE sensor element to the attachment 10, it is possible to detect elastic waves generated when a foreign matter is caught between the shank 41 and the insertion hole 15. When at least one of the acceleration sensor element or the AE sensor element is aligned radially with respect to the insertion hole 15, the distance to the origin of the elastic wave is shortened, so that the attenuation of the elastic wave can be reduced and the SN ratio (signal / noise ratio) can be increased. As a result, the occurrence of an abnormality in the attachment 10 can be detected early.

[0064] When a force sensor element is used as the sensor element 31, the force sensor element is disposed in a portion thinner than the base 11. That is, the force sensor element can be disposed in a portion of the attachment body 1 where distortion is likely to occur. Therefore, with this configuration, it is easy to improve the accuracy of measuring distortion generated in the attachment 10 by using the force sensor element.

[0065] When a temperature sensor element is used as the sensor element 31, the temperature sensor elements are arranged radially with respect to the insertion hole 15, and therefore the heat conducted from the tool holder 4 can be properly detected. That is, when cooling water passes through the cooling passage 16, the base 11 and the fixing screw 2 are cooled by the cooling water, but the outer peripheral wall 14 of the gripping part 13, which is not in direct contact with the cooling passage 16, is less affected by the cooling water. As a result, by arranging the temperature sensor element on the gripping part outer peripheral surface 142, the heat conducted from the tool holder 4 can be properly detected while reducing the effect of the cooling water.

[0066] Referring to FIG. 2, the plurality of substrates 32 are electrically connected to the sensor element 31. The plurality of substrates 32 are attached so as to be aligned with the outer peripheral surface of the attachment body 1. The attachment of the substrates 32 to the attachment body 1 is performed, for example, by gluing or screwing. The sensor element 31 is disposed in an area located in the second direction D2 from the substrate 32. The plurality of substrates 32 are electrically connected to each other by wiring 36. In this embodiment, the detection area 312 of the plurality of sensor elements 31 is disposed at an interval in the second direction D2 with respect to the edge of the plurality of substrates 32 located closest to the second direction D2. With this configuration, the sensor element 31 can be disposed on the grip portion outer peripheral surface 142 without being disposed on the substrate 32. In this embodiment, all the substrates 32 are disposed along the base outer peripheral surface 111 of the attachment body 1.

[0067] The substrate 32 is disposed along the base outer peripheral surface 111, but may be disposed along the gripping portion outer peripheral surface 142. The substrate 32 may be disposed across the base outer peripheral surface 111 and the outer peripheral surface of the gripping portion 13. The attachment 10 has a plurality of substrates 32, but may have only one substrate 32.

[0068] The power supply unit 33 is electrically connected to the substrate 32 via wiring 36, and supplies power to the sensor element 31. In this embodiment, the power supply unit 33 is a secondary battery. The power supply unit 33 is not limited to a secondary battery, and may be, for example, a primary battery or a capacitor. The power supply unit 33 is removably held by a holder 331 attached to the outer circumferential surface of the attachment body 1.

[0069] The AD converter 34 converts an electric signal (hereinafter, sometimes referred to as a detection signal) generated in response to detection by the sensor element 31 into a digital signal. The detection signal is input to the wireless communication unit 35 through the AD converter 34. The wireless communication unit 35 is a wireless communication module attached to the substrate 32. The wireless communication unit 35 is electrically connected to the sensor element 31, and can receive a digital signal converted from the detection signal. The wireless communication unit 35 transmits the digital signal input from the AD converter 34 to the outside. That is, the wireless communication unit 35 can transmit a signal generated in response to detection by the sensor element 31 to the outside.

[0070] (Case 7 Structure) FIG. 6 is a cross-sectional view of the attachment 10 in a state in which the case 7 is attached to the attachment body 1, and is a cross-sectional view including the line CC in FIG. 1. In FIG. 6, a part of the attachment body 1 is omitted. Referring to FIG. 6, the case 7 is attached to the outer circumferential surface of the attachment body 1. At least the sensor element 31 is housed in the case 7. In this embodiment, the sensor unit 3 (the multiple sensor elements 31, the multiple boards 32, the power supply unit 33, the AD converter 34, and the wireless communication unit 35) is housed in the case 7. Examples of materials constituting the case 7 include synthetic resin and metal. Examples of metal include aluminum alloys and iron alloys (steel such as stainless steel). The case 7 is removably attached to the outer circumferential surface of the attachment body 1. The case 7 can be attached to the outer circumferential surface of the attachment body 1 by, for example, screwing, snap fitting, inserting, or bonding.

[0071] When the case 7 is made of a material with high radio wave shielding properties (e.g., aluminum alloy, iron alloy), a part of the case 7 may be made of a material with lower radio wave shielding properties (a material with high radio wave permeability) than the other parts. Examples of materials with low radio wave shielding properties include synthetic resin, pulp, rubber, wood, and cloth. This makes it possible to reduce degradation of communication performance (reduction in radio wave intensity) even if the wireless communication unit 35 is covered by the case 7.

[0072] 6, the case 7 includes a first housing section 71 that houses the plurality of sensor elements 31, the plurality of boards 32, the AD converter 34, and the wireless communication section 35, and a second housing section 72 that houses the power supply section 33. The first housing section 71 communicates with the second housing section 72. The inside of the case 7 is a sealed space separated from the space outside the case 7.

[0073] The first housing section 71 is formed in a cross-sectional arc shape when viewed along the second direction D2. The first housing section 71 is disposed at an interval with respect to the outer peripheral surface of the attachment body 1. In the space between the outer peripheral surface of the attachment body 1 and the first housing section 71, a plurality of sensor elements 31, a plurality of boards 32, an AD converter 34, and a wireless communication section 35 are disposed. The second housing section 72 protrudes radially outward from the first housing section 71. An opening surface is formed on the protruding tip surface of the second housing section 72, and the opening surface is closed by a lid 721 so as to be openable and closable. The power supply section 33 is disposed in the space between the outer peripheral surface of the attachment body 1 and the second housing section 72. When the lid 721 is removed from the opening surface, the power supply section 33 can be removed through the opening surface. According to the case 7 according to this embodiment, the power supply section 33 can be replaced without removing the entire case 7 by removing the lid 721 from the opening surface.

[0074] The attachment 10 further includes a seal portion 37 disposed between the outer peripheral surface of the attachment body 1 and the outer edge of the case 7. Referring to FIG. 2, the seal portion 37 surrounds at least the sensor element 31. In this embodiment, the seal portion 37 surrounds the multiple sensor elements 31, the multiple boards 32, the power supply portion 33, the AD converter 34, and the wireless communication portion 35. This configuration can reduce the amount of liquid (e.g., oil, water) that penetrates into the case 7. Examples of the seal portion 37 include rubber and soft resin. Examples of the rubber include ethylene propylene rubber, urethane rubber, silicone rubber, and fluororubber.

[0075] The inside of the first housing portion 71 may be filled with a filler material with the components such as the sensor element 31 arranged therein. As a result, the components such as the sensor element 31 are fixed not only to the outer peripheral surface of the attachment body 1 but also to the case 7. By fixing the components such as the sensor element 31 to the outer peripheral surface of the attachment body 1 and the case 7, the effect of centrifugal force can be reduced even if the attachment 10 rotates. The inside of the second housing portion 72 does not need to be filled with a filler material. As a result, the work of replacing the power supply unit 33 is less likely to be hindered.

[0076] (operation) Referring to FIG. 1, when the spindle rotates about the rotation axis R1, the attachment 10 rotates in a third direction R3 or a fourth direction R4. Then, the tool holder 4 rotates according to the rotation of the attachment 10. The cutting tool 5 attached to the tool holder 4 comes into contact with the workpiece, so that the workpiece is machined. At this time, the physical quantities such as strain and temperature generated in the attachment 10 are detected by the sensor element 31. The information on the physical quantities, which is an analog signal, is converted into a digital signal by the AD converter 34, and then transmitted to the outside by the wireless communication unit 35. This signal is received and analyzed outside. As a result of analyzing the physical quantities generated in the attachment 10, the state of the cutting tool 5 is grasped.

[0077] (First Modification) When a force sensor element is employed as the sensor element 31, the attachment 10 may be formed as follows: The sensor element 31 according to this modification is a force sensor element 311, more specifically, a strain sensor element.

[0078] FIG. 7 is a schematic perspective view showing the structure of the attachment 10 according to the modified example. FIG. 8 is a schematic cross-sectional view of the base 11 and the grip 13 in the attachment 10 according to the modified example. FIG. 9 is a schematic enlarged view of the A portion in FIG. 8. FIG. 10 is a schematic bottom view of the attachment 10 according to the modified example seen in the first direction D1. FIG. 11 is a schematic cross-sectional view showing the state in which the case 7 is attached in the attachment 10 according to the modified example, and shows a cross section including the line DD in FIG. 7. FIG. 11 mainly shows a schematic cross-sectional view of the base 11, the grip 13, and the case 7. The case 7 is omitted in FIGS. 7 to 10.

[0079] 7 to 9, the gripper outer peripheral surface 142 has a slit 145 formed along an arc centered on the rotation axis R1. The slit 145 is formed along the third direction R3 and the fourth direction R4. With reference to FIG. 8, the minimum distance L4 between the bottom surface of the slit 145 and the rotation axis R1 is shorter than the minimum distance L5 between the bottom surface of the arrangement portion 144 and the rotation axis R1. With reference to FIG. 9, the depth DP2 of the slit 145 from the gripper outer peripheral surface 142 is deeper than the depth DP1 of the arrangement portion 144 from the gripper outer peripheral surface 142. With reference to FIG. 7, the slit 145 is formed on the gripper outer peripheral surface 142 over the entire circumference in the third direction R3, and is formed in an annular shape. The slit 145 may be interrupted in a part of the third direction R3, that is, may be formed in a C-shape. The slit 145 may be formed continuously or intermittently along the third direction R3.

[0080] 9, the detection area 312 of the force sensor element 311 is attached in the arrangement portion 144 so as to straddle the slit 145. Referring to FIG. 10, the angle θ1 formed by the line segment connecting the center of the detection area 312 of each force sensor element 311 and the rotation axis R1 is 90 degrees when viewed in the first direction D1. That is, the multiple force sensor elements 311 are arranged at 90 degree intervals when viewed in the first direction D1. With this configuration, the force sensor element 311 can easily appropriately detect the strain occurring in the attachment 10.

[0081] In this modification, the power supply unit 33 is composed of two secondary batteries 332. Referring to FIG. 10, the power supply units 33 according to the first modification are arranged at regular intervals on the outer circumferential surface of the attachment body 1. When the attachment 10 is viewed along the first direction D1, the angle θ2 between the line segments connecting the center of the power supply unit 33 and the rotation axis R1 is 90 degrees. In other words, the multiple power supply units 33 are arranged at regular intervals in the third direction R3. With this configuration, the center of gravity of the attachment 10 is likely to be located on the rotation axis R1. Therefore, by adopting the attachment 10 according to the first modification, stable rotation can be obtained and deterioration of balance during rotation can be reduced.

[0082] 11, case 7 includes a ring-shaped fixing member 73 fixed to attachment body 1, and a cylindrical cover member 74. Case 7 is a rotating body centered on rotation axis R1 of attachment body 1. Therefore, attachment 10 according to this modification can achieve stable rotation even when case 7 is attached to attachment body 1, and deterioration of balance during rotation can be reduced.

[0083] The fixing member 73 has an inner circumferential surface facing the outer circumferential surface of the attachment body 1. In this modification, an O-ring 371 serving as a seal portion 37 is disposed between the inner circumferential surface of the fixing member 73 and the outer circumferential surface of the attachment body 1, thereby fixing the fixing member 73 to the outer circumferential surface of the attachment body 1. The fixing member 73 may be fixed to the outer circumferential surface of the attachment body 1 by press-fitting. The fixing member 73 has a plurality of through holes 731 penetrating both end faces in the first direction D1. A screw device 75 is inserted into each of the plurality of through holes 731.

[0084] The cover member 74 covers the sensor unit 3 (the multiple sensor elements 31, the multiple substrates 32, the power supply unit 33, the AD converter 34, and the wireless communication unit 35). The cover member 74 includes a cylindrical outer peripheral portion 741, a first attachment portion 742 that protrudes in a tapered shape from an end of the outer peripheral portion in the second direction D2, and a second attachment portion 743 that protrudes from an end of the outer peripheral portion in the first direction D1 toward the central axis. A female screw 744 is formed in the first attachment portion 742 at a portion facing the attachment body 1. The female screw 744 is configured to be screwable into a male screw 146 formed on the outer peripheral surface (the gripping portion outer peripheral surface 142) of the attachment body 1. When the female screw 744 of the first attachment portion 742 is screwed into the male screw 146 of the attachment body 1, the second attachment portion 743 is adjacent to the fixing member 73. The second mounting portion 743 has a plurality of screw holes 745 formed at positions corresponding to the plurality of through holes 731 of the fixing member 73. With the female threads 744 of the first mounting portion 742 screwed into the male threads 146 of the attachment body 1, the screw device 75 passed through the through hole 731 of the fixing member 73 is screwed into the screw hole 745 of the second mounting portion 743. In this way, the case 7 is attached to the outer circumferential surface of the attachment body 1.

[0085] (Other variations) In the embodiment, the third direction R3 is a clockwise direction when viewed in the second direction D2, and the fourth direction R4 is a counterclockwise direction when viewed in the second direction D2, but the fourth direction R4 may be a clockwise direction when viewed in the second direction D2, and the third direction R3 may be a counterclockwise direction when viewed in the second direction D2.

[0086] In the embodiment, the case where the sensor element 31 is any one of a force sensor element, an acceleration sensor element, and a temperature sensor element has been described. As the sensor element 31, a plurality of sensor elements 31 selected from a force sensor element, an acceleration sensor element, and a temperature sensor element may be adopted. For example, a force sensor element may be adopted as the first sensor element, and a temperature sensor may be adopted as the second sensor element. For example, an acceleration sensor element may be adopted as the first sensor element, and a temperature sensor may be adopted as the second sensor element. For example, a force sensor element may be adopted as the first sensor element, and an acceleration sensor element may be adopted as the second sensor element. As the sensor element 31 included in the sensor unit 3, a sensor element 31 (for example, a gyro sensor element) that detects a physical quantity other than a force sensor element, an acceleration sensor element, and a temperature sensor element may be adopted.

[0087] In the above embodiment, the machine tool that mainly performs turning processing has been described, but the machine tool may be a multi-tasking machine or a lathe such as a general-purpose lathe or an NC lathe. That is, the tool attachment portion 6 is not limited to a spindle. For example, when the machine tool is a lathe, the tool attachment portion 6 may be a tool rest. That is, the attachment 10 according to the present disclosure is not limited to an attachment 10 used for a tool holder 4 for a turning tool, but may be an attachment 10 used for a tool holder 4 for a turning tool (including a tool holder and a boring bar). A turning tool (including an insert) may be used as the cutting tool 5.

[0088] The sensor unit 3 may further include at least one component selected from the group consisting of a switch and a variable resistor mounted on the substrate 32.

[0089] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0090] 10 attachment, 1 attachment body, 11 base, 111 base outer peripheral surface, 112 groove, 113 flange surface, 114 first end, 115 second end, 116 position regulation portion, 12 shank portion, 121 protrusion, 122 inner peripheral surface, 123 outer peripheral surface, 13 grip portion, 14 outer peripheral wall, 141 grip portion inner peripheral surface, 142 grip portion outer peripheral surface, 143 contact surface, 144 arrangement portion, 145 slit, 146 male thread, 15 insertion hole, 151 hole bottom surface, 152 insertion hole, 16 cooling path, 2 fixing screw, 21 shaft portion, 211 screw, 22 head portion, 221 swivel hole, 3 sensor portion, 31 sensor element, 311 force sensor element, 312 detection area, 313 Connection portion, 32 board, 33 power supply portion, 331 holder, 332 secondary battery, 34 AD converter, 35 wireless communication portion, 36 wiring, 37 sealing portion, 371 O-ring, 4 tool holder, 41 shank, 5 cutting tool, 6 tool mounting portion, 61 insertion opening, 7 case, 73 fixing member, 731 through hole, 74 cover member, 741 outer periphery, 742 first mounting portion, 743 second mounting portion, 744 female thread, 745 screw hole, 75 screw tool, K1 virtual plane, K2 virtual circle, P1 part, P2 vertex, R1 rotation axis, D1 first direction, D2 second direction, R3 third direction, R4 fourth direction.

Claims

1. an attachment body that connects a tool mounting portion included in a machine tool and a tool holder; a sensor unit attached to the attachment body to which the tool holder is integrally fixed so as not to move relative to the attachment body during machining, and configured to detect a physical quantity of the attachment body; Tool holder attachment.

2. The sensor unit includes: At least one sensor element that detects a physical quantity of the attachment body; The tool holder attachment according to claim 1 , further comprising: a wireless communication unit configured to transmit a signal generated in response to detection by the sensor element to an outside.

3. The sensor unit includes: At least one sensor element that detects a physical quantity of the attachment body; 2. The tool holder attachment of claim 1, further comprising: a power supply for supplying power to the sensor element.

4. The sensor unit has at least one sensor element that detects a physical quantity of the attachment body, The tool holder attachment of claim 1 , further comprising a case in which the at least one sensor element is housed.

5. The attachment comprises: The tool holder attachment according to claim 4 , further comprising a seal portion surrounding the at least one sensor element between an outer circumferential surface of the attachment body and the case.

6. The attachment body includes: A base and a shank portion protruding from the base portion along a first direction from the tool holder toward the tool attachment portion and attached to the tool attachment portion; a gripping portion protruding from the base portion along a second direction from the tool attachment portion toward the tool holder and including an insertion hole into which a shank of the tool holder is inserted; The attachment of a tool holder according to claim 1 , wherein an outer peripheral surface of the shank portion includes a tapered surface that approaches a central axis as it progresses in the first direction.

7. The attachment body includes: A base and a shank portion protruding from the base portion along a first direction from the tool holder toward the tool attachment portion and attached to the tool attachment portion; a gripping portion protruding from the base portion along a second direction from the tool attachment portion toward the tool holder and including an insertion hole into which a shank of the tool holder is inserted; The attachment of a tool holder according to claim 1 , wherein an inner circumferential surface surrounding the insertion hole includes a tapered surface that approaches a central axis as it progresses in the first direction.

8. An attachment body that connects a tool mounting portion included in a machine tool and a tool holder; a sensor unit attached to the attachment body and having at least one sensor element that detects a physical quantity of the attachment body; The attachment body includes: A base and a shank portion protruding from the base portion along a first direction from the tool holder toward the tool attachment portion and attached to the tool attachment portion; a gripping portion protruding from the base portion along a second direction from the tool attachment portion toward the tool holder and including an insertion hole into which a shank of the tool holder is inserted; The outer peripheral surface of the shank portion includes a tapered surface that approaches a central axis as it advances in the first direction, A tool holder attachment, wherein an imaginary plane perpendicular to the second direction and intersecting the at least one sensor element intersects the insertion hole.

9. An attachment body that connects a tool mounting portion included in a machine tool and a tool holder; a sensor unit attached to the attachment body and having at least one sensor element that detects a physical quantity of the attachment body; The attachment body includes: A base and a shank portion protruding from the base portion along a first direction from the tool holder toward the tool attachment portion and attached to the tool attachment portion; a gripping portion protruding from the base portion along a second direction from the tool attachment portion toward the tool holder and including an insertion hole into which a shank of the tool holder is inserted; an inner circumferential surface surrounding the insertion hole includes a tapered surface that approaches a central axis as it advances in the first direction, A tool holder attachment, wherein an imaginary plane perpendicular to the second direction and intersecting the at least one sensor element intersects the insertion hole.

10. the at least one sensor element includes a detection area to which the physical quantity is input; 10. The attachment of claim 8 or 9, wherein the imaginary plane intersecting the detection area intersects the insertion hole.

11. The sensor unit has at least one sensor element that detects a physical quantity of the attachment body, 10. The tool holder attachment according to claim 1, wherein a recess is formed in an outer peripheral surface of the attachment body, in which at least a portion of the at least one sensor element is disposed.

12. An attachment body that connects a tool mounting portion included in a machine tool and a tool holder; a sensor unit attached to the attachment body and having at least one sensor element that detects a physical quantity of the attachment body; The sensor unit includes: A substrate; Wiring electrically connecting the substrate and the at least one sensor element; and Attachment of a tool holder, wherein the at least one sensor element is positioned in an area relative to the substrate in a second direction from the tool attachment portion toward the tool holder.

13. the gripping portion has an arrangement portion in which the at least one sensor element is arranged and which is recessed from an outer circumferential surface of the gripping portion; a thickness between an outer circumferential surface included in the gripping portion and an inner circumferential surface surrounding the insertion hole is configured to change in a third direction along an intersection line between the imaginary plane and the inner circumferential surface; 10. The attachment of claim 8 or 9, wherein the arrangement portion is formed at a position shifted in the third direction with respect to a portion of the outer peripheral surface of the gripping portion that corresponds to the minimum value of the thickness.

14. The sensor unit has at least one sensor element that detects a physical quantity of the attachment body, Attachment of a tool holder according to claim 1 , claim 8 , claim 9 and claim 12 , wherein the at least one sensor element comprises a force sensor element.

15. The sensor unit has at least one sensor element that detects a physical quantity of the attachment body, Attachment of a tool holder according to any one of claims 1, 8, 9 and 12, wherein the at least one sensor element comprises an acceleration sensor element or an AE sensor element.

16. The sensor unit has at least one sensor element that detects a physical quantity of the attachment body, 13. The tool holder attachment of claim 1, claim 8, claim 9 and claim 12, wherein the at least one sensor element comprises a temperature sensor element.

17. The attachment body has an outer peripheral surface included in the attachment body, and a slit is formed along an intersection line between the virtual plane and the outer peripheral surface, The at least one sensor element includes a force sensor element mounted across the slit.

10. An attachment for a tool holder according to claim 8 or claim 9.

18. 10. The attachment for a tool holder according to claim 6, wherein an outer peripheral surface of the shank portion and an inner peripheral surface surrounding the insertion hole have the same shape.

19. 10. The attachment for a tool holder according to claim 6, wherein an outer peripheral surface of the shank portion and an inner peripheral surface surrounding the insertion hole have different shapes.

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