JP2024130753A - Tools and clamp bolts - Google Patents

Abstract

To provide a tool and a clamp bolt improving a tool life.SOLUTION: A tool 100 is equipped with a cutter 41, a tool holder 20, and a clamp bolt 51 for fixing the cutter 41 to the tool holder 20. The clamp bolt 51 extends in an axial direction of a rotation shaft of the tool holder 20, and includes a base portion 61 pressing the cutter 41 to the tool holder 20 in an axial direction of the rotation shaft. The base portion 61 is provided with a fluid discharge groove 76 that has a groove shape rotating around the rotation shaft while opening while turning outward in a radial direction of the rotation shaft of the tool holder 20 and discharges coolant supplied from the tool holder 20 toward the cutter 41.SELECTED DRAWING: Figure 1

Description

This invention relates to a tool and a clamp bolt.

For example, Japanese Patent Application Laid-Open No. 2004-276136 (Patent Document 1) discloses a fastening bolt used to fasten a face milling cutter attached to the lower end of an arbor. The fastening bolt has a male threaded portion that screws into the female threaded portion of the arbor, and a body portion that presses against the bottom surface of the face milling cutter.

The fastening bolt is provided with a flow passage within the bolt. The flow passage within the bolt extends along the axis of the male threaded portion and is composed of a main flow passage through which the cutting oil supplied from the arbor flows, and multiple branch flow passages that branch off from the end of the main flow passage and are provided with a downward incline toward the outer circumferential surface of the main body portion, and discharge the cutting oil toward the throw-away tip of the face milling cutter.

JP 2004-276136 A

In the fastening bolt disclosed in the above-mentioned Patent Document 1, cutting oil is discharged toward the machining point of the workpiece through the openings of multiple branch flow paths. However, due to flow path resistance in each branch flow path, the amount of cutting oil discharged may not be sufficient, and because the multiple branch flow paths open at intervals in the rotational direction (circumferential direction) of the face milling cutter, there is a possibility that the amount of cutting oil supplied to the machining point of the workpiece may vary. In such cases, the supply of cutting oil may not be effective enough in suppressing tool wear, and there is a concern that the tool life may be shortened.

In addition, in the fastening bolt disclosed in the above-mentioned Patent Document 1, the main flow path of the flow path inside the bolt is provided in the male thread portion that is screwed into the arbor. With this configuration, the rigidity of the male thread portion cannot be sufficiently ensured, and there is a concern that the tool life will be shortened due to damage to the male thread portion.

The object of this invention is to solve the above problems and provide a tool and clamp bolt that improves tool life.

A tool according to one aspect of the present invention includes a cutter, a tool holder, and a clamp bolt for fixing the cutter to the tool holder. The clamp bolt includes a base. The base extends in the axial direction of the rotation shaft of the tool holder and presses the cutter against the tool holder in the axial direction of the rotation shaft. The base is provided with a fluid discharge groove for discharging fluid supplied from the tool holder toward the cutter. The fluid discharge groove has a groove shape that opens toward the radially outward side of the rotation shaft and revolves around the rotation shaft.

A clamp bolt according to one aspect of the present invention is a clamp bolt for fixing a cutter to a tool holder. The clamp bolt has a base. The base extends in the axial direction of the rotation shaft of the tool holder and presses the cutter against the tool holder in the axial direction of the rotation shaft. The base is provided with a fluid discharge groove that discharges fluid supplied from the tool holder toward the cutter. The fluid discharge groove has a groove shape that opens toward the radially outward direction of the rotation shaft and revolves around the rotation shaft.

A tool according to another aspect of the present invention includes a cutter, a tool holder, and a clamp bolt for fixing the cutter to the tool holder. The clamp bolt includes a male threaded portion and a base. The male threaded portion extends on the rotation axis of the tool holder and is screwed into the tool holder. The base protrudes radially outward from the male threaded portion and extends in the axial direction of the rotation axis, pressing the cutter against the tool holder in the axial direction of the rotation axis. The base has an opposing surface. The opposing surface faces the tool holder in the axial direction of the rotation axis. A fluid passage is provided in the base. The fluid passage opens into the opposing surface, and fluid supplied from the tool holder is introduced through the opening and discharged toward the cutter.

A clamp bolt according to another aspect of the present invention is a clamp bolt for fixing a cutter to a tool holder. The clamp bolt has a male threaded portion and a base portion. The male threaded portion extends on the rotation axis of the tool holder and is screwed into the tool holder. The base portion projects radially outward from the male threaded portion and extends in the axial direction of the rotation axis, pressing the cutter against the tool holder in the axial direction of the rotation axis. The base portion has an opposing surface. The opposing surface faces the tool holder in the axial direction of the rotation axis. A fluid passage is provided in the base portion. The fluid passage opens into the opposing surface, and fluid supplied from the tool holder is introduced through the opening and discharged toward the cutter.

This invention makes it possible to provide a tool and a clamp bolt that improves tool life.

1 is a partial cross-sectional view showing a tool according to an embodiment of the present invention. FIG. 2 is a perspective view showing a tool holder in FIG. 1 . FIG. 2 is a side view showing the clamp bolt in FIG. 1 . FIG. 2 is a perspective view showing a clamp bolt in FIG. 1 . 2 is an enlarged cross-sectional view showing an area surrounded by a two-dot chain line V in FIG. 1 . FIG. 2 is a cross-sectional view showing a modified example of the clamp bolt in FIG. 1 .

The embodiment of the present invention will be described with reference to the drawings. Note that in the drawings referred to below, the same or equivalent components are given the same numbers.

Figure 1 is a partial cross-sectional view showing a tool according to an embodiment of the present invention. In the figure, the tool holder 20 (described below) is shown in its external shape, and the cutter 41 and clamp bolt 51 (described below) are shown in cross-sectional shape.

Referring to FIG. 1, the tool 100 in this embodiment is used to machine a workpiece. The tool 100 is attached to the spindle of a machine tool such as a machining center or a multitasking machine, and machines the workpiece by rotating about a central axis 101.

First, the overall structure of the tool 100 will be described. The tool 100 has a tool holder 20, a cutter 41, and a clamp bolt 51. The tool holder 20 holds the cutter 41 and is configured to be detachable from the spindle of the machine tool. The cutter 41 is the part that comes into contact with the workpiece to be machined and machines the workpiece. The cutter 41 is held by the tool holder 20. The clamp bolt 51 is a fastener for fixing the cutter 41 to the tool holder 20.

When machining a workpiece, the rotational motion from the spindle of the machine tool is transmitted to the tool 100 through the tool holder 20. The tool holder 20, cutter 41, and clamp bolt 51 rotate together about a central axis 101. The central axis 101 corresponds to the rotation axis of the tool 100. The central axis 101 corresponds to the respective rotation axes of the tool holder 20, cutter 41, and clamp bolt 51.

Figure 2 is a perspective view showing the tool holder in Figure 1. Referring to Figure 2, the tool holder 20 has a holder body portion 21 and a shank portion 22. The holder body portion 21 and the shank portion 22 extend about the central axis 101.

The holder body 21 is a portion that holds the cutter 41. The shank portion 22 is a portion that is fixed to the spindle of a machine tool or that is held by an arm in an automatic tool changer (ATC: Automatic Tool Changer) of the machine tool. The specification of the shank portion 22 is CAPTO. The specification of the shank portion 22 is not particularly limited, and may be, for example, BT or HSK.

The holder body 21 extends cylindrically around the central axis 101. The end of the holder body 21 in the axial direction of the central axis 101 is connected to the shank 22.

The holder main body 21 has a first shaft portion 26 and a second shaft portion 31. The first shaft portion 26 and the second shaft portion 31 are arranged in series in the axial direction of the central axis 101. The diameter of the first shaft portion 26 centered on the central axis 101 is larger than the diameter of the second shaft portion 31 centered on the central axis 101. The first shaft portion 26 is connected to the shank portion 22. The first shaft portion 26 has a step surface 26a. The step surface 26a is a plane perpendicular to the central axis 101. The second shaft portion 31 protrudes from the step surface 26a in the axial direction of the central axis 101. The step surface 26a extends in a ring shape around the second shaft portion 31.

The first shaft portion 26 is provided with a plurality of keys 27. The keys 27 are provided so as to protrude from the stepped surface 26a at a position spaced radially outward from the second shaft portion 31 with respect to the central axis 101. The multiple keys 27 are provided at intervals from one another in the circumferential direction of the central axis 101.

The tool holder 20 has a holder end face 31a. The holder end face 31a is a plane perpendicular to the central axis 101. The holder end face 31a is provided at the end of the tool holder 20 (holder body portion 21) in the axial direction of the central axis 101. The holder end face 31a corresponds to the end face of the second shaft portion 31 that is located at the end that protrudes from the step surface 26a. The holder end face 31a extends in a ring shape around the opening of the female thread portion 36 described below.

The tool holder 20 has a female thread 36. The female thread 36 is provided on the inner peripheral surface of the holder body 21. The female thread 36 extends about the central axis 101 and opens to the holder end face 31a.

The tool holder 20 is further provided with a first coolant supply passage 32p and a second coolant supply passage 32q. The first coolant supply passage 32p and the second coolant supply passage 32q are provided in the holder body 21.

The first coolant supply passage 32p and the second coolant supply passage 32q are provided in the second shaft portion 31. The second coolant supply passage 32q is recessed from the outer peripheral surface 31c of the second shaft portion 31, extends in the axial direction of the central axis 101, and has a groove shape that opens to the holder end surface 31a. The first coolant supply passage 32p extends in the radial direction of the central axis 101. The first coolant supply passage 32p communicates with the space inside the second shaft portion 31 at its radially inner end of the central axis 101, and communicates with the second coolant supply passage 32q at its radially outer end of the central axis 101.

The first coolant supply passage 32p and the second coolant supply passage 32q form a pair to form the coolant supply passage 32. The multiple coolant supply passages 32 are provided at intervals in the circumferential direction of the central axis 101. The multiple coolant supply passages 32 are provided at equal intervals in the circumferential direction of the central axis 101.

When the workpiece is machined by the tool 100, coolant is supplied from the spindle of the machine tool to the space inside the tool holder 20. As shown by the dotted arrow in FIG. 2, the coolant supplied to the space inside the tool holder 20 passes through the first coolant supply passage 32p and the second coolant supply passage 32q in the listed order, and is supplied toward the clamp bolt 51.

Referring to FIG. 1, the cutter 41 has a fitting portion 46. The fitting portion 46 extends cylindrically around the central axis 101. The fitting portion 46 is fitted onto the outer periphery of the second shaft portion 31. The fitting portion 46 abuts against the step surface 26a in the axial direction of the central axis 101. The second coolant supply passage 32q is covered by the fitting portion 46 on the radially outer side of the central axis 101.

The fitting portion 46 is provided with a number of key grooves 44. A number of keys 27 on the tool holder 20 side are inserted into the key grooves 44, respectively. The fitting structure of the keys 27 and the key grooves 44 functions as a rotation stopper for the cutter 41 relative to the tool holder 20.

The fitting portion 46 has a protrusion 43. The protrusion 43 has a convex shape that protrudes from the fitting portion 46 in the axial direction of the central axis 101. The protrusion 43 is provided radially inward of the central axis 101 from the cutting edge portion 47 described below.

The cutter 41 further has a cutting edge portion 47. The cutting edge portion 47 has a cutting edge shape for processing a workpiece. The cutting edge portion 47 protrudes from the fitting portion 46 in the axial direction of the central axis 101.

In this embodiment, the cutter 41 is a skiving cutter for machining a gear into a workpiece. The cutter 41 is integrally formed from a metal such as high speed steel or cemented carbide. While the workpiece and the tool 100 are rotated synchronously with each other, the tip 42 of the cutter 41 (cutting edge portion 47) in the axial direction of the central axis 101 and in the radial direction of the central axis 101 is brought into contact with the workpiece to form a tooth profile on the outer or inner surface of the workpiece.

The cutter in the present invention is not limited to the above-mentioned skiving cutter, but may be, for example, a milling cutter to which multiple throw-away tips are detachably attached.

Figure 3 is a side view of the clamp bolt in Figure 1. Figure 4 is a perspective view of the clamp bolt in Figure 1. Figure 5 is an enlarged cross-sectional view of the area surrounded by the two-dot chain line V in Figure 1.

Referring to Figures 1 to 5, the clamp bolt 51 is integrally formed from metal. The clamp bolt 51 has a base 61, a male threaded portion 56, and a head portion 57.

The male thread portion 56 is the portion that is connected to the tool holder 20. The male thread portion 56 extends on the axis of the central axis 101. The male thread portion 56 is made of a solid shaft body. The male thread portion 56 is screwed into the female thread portion 36 of the tool holder 20.

The base 61 extends around the central axis 101. The base 61 protrudes radially outward from the central axis 101 beyond the male threaded portion 56. The diameter of the base 61 around the central axis 101 is larger than the diameter of the male threaded portion 56 around the central axis 101. The base 61 is disposed inside the cutting blade portion 47 of the cutter 41.

The base 61 has an opposing surface 61a and a bolt end surface 61b. The opposing surface 61a and the bolt end surface 61b are each a plane perpendicular to the central axis 101. The bolt end surface 61b faces the opposite side to the opposing surface 61a in the axial direction of the central axis 101.

The opposing surface 61a faces the holder end surface 31a of the tool holder 20 in the axial direction of the central axis 101. The opposing surface 61a abuts against the convex portion 43 of the cutter 41 in the axial direction of the central axis 101. The fastening force of the male thread portion 56 against the female thread portion 36 causes the base 61 to press the cutter 41 (fitting portion 46) against the tool holder 20 in the axial direction of the central axis 101. The fitting portion 46 is sandwiched between the step surface 26a and the opposing surface 61a in the axial direction of the central axis 101, thereby fixing the cutter 41 to the tool holder 20.

A gap 81 is provided between the opposing surface 61a and the holder end surface 31a. The gap 81 is a space that has a constant height in the axial direction of the central axis 101 and extends in a ring shape around the central axis 101. The gap 81 is defined and formed between the male thread portion 56 and the protruding portion 43 in the radial direction of the central axis 101. The second coolant supply passage 32q is in communication with the gap 81. As an example, the height of the gap 81 in the axial direction of the central axis 101 is in the range of 0.5 mm to 1.5 mm.

The head 57 is provided on the axis of the central shaft 101. The head 57 protrudes from the bolt end face 61b in the axial direction of the central shaft 101. When viewed in the axial direction of the central shaft 101, the head 57 has a hexagonal shape that allows a wrench or the like to be hooked.

Next, we will explain the structure of the clamp bolt 51, which ejects the coolant supplied from the tool holder 20 toward the cutter 41.

Referring to Figures 1 to 5, the base 61 is provided with a coolant passage 70. The coolant passage 70 has a plurality of first openings 72 and a second opening 77. The coolant passage 70 extends between the plurality of first openings 72 and the second openings 77. Each of the first openings 72 serves as an inlet for coolant from the tool holder 20 to the clamp bolt 51. The second openings 77 serve as an outlet for coolant from the clamp bolt 51 to the cutter 41.

The multiple first openings 72 open to the opposing surface 61a. The multiple first openings 72 have a circular opening shape. The multiple first openings 72 are arranged at intervals from each other in the circumferential direction of the central axis 101. The coolant passage 70 communicates with the gap 81 through the multiple first openings 72.

The second opening 77 opens into the outer peripheral surface 61c of the base 61. The second opening 77 is disposed between the opposing surface 61a and the bolt end surface 61b in the axial direction of the central axis 101. The second opening 77 has a constant height in the axial direction of the central axis 101 and forms a band-like opening shape that rotates 360° around the central axis 101.

The coolant passage 70 is composed of multiple coolant introduction holes 71 and a coolant discharge groove 76. The coolant introduction holes 71 introduce coolant supplied from the tool holder 20. The coolant discharge groove 76 discharges the coolant that has flowed in from the coolant introduction holes 71 toward the cutter 41.

The multiple coolant introduction holes 71 each have multiple first openings 72. The coolant introduction holes 71 extend from the first openings 72 in a direction away from the opposing surface 61a in the axial direction of the central axis 101, and are connected at their ends to the coolant discharge grooves 76. The multiple coolant introduction holes 71 are spaced apart from one another in the circumferential direction of the central axis 101. The multiple coolant introduction holes 71 are evenly spaced apart in the circumferential direction of the central axis 101.

The coolant introduction hole 71 extends obliquely relative to the central axis 101. As the coolant introduction hole 71 approaches the coolant discharge groove 76 from the first opening 72, it shifts from the radial inner side to the radial outer side of the central axis 101.

The coolant introduction hole 71 is not limited to the above, and may extend, for example, parallel to the central axis 101, or may extend so as to shift in the direction of rotation of the tool 100 or in the opposite direction to the direction of rotation of the tool 100 as it approaches the coolant discharge groove 76 from the first opening 72.

The coolant discharge groove 76 has a second opening 77. The coolant discharge groove 76 has a groove shape that opens toward the radially outward direction of the central axis 101 at the second opening 77 and revolves around the central axis 101.

The coolant discharge groove 76 is provided parallel to a plane perpendicular to the central axis 101. The coolant discharge groove 76 has a constant height in the axial direction of the central axis 101 and defines a ring-shaped space that rotates 360° around the central axis 101.

The base 61 has a pair of walls 64 (64u, 64v) that form the groove walls of the coolant discharge groove 76. Each wall 64 is formed of a plane perpendicular to the central axis 101. The pair of walls 64 face each other in the axial direction of the central axis 101. The coolant introduction hole 71 opens in the wall 64u.

The height Ta of the coolant discharge groove 76 in the axial direction of the central axis 101 (the distance between a pair of wall portions 64) is, for example, in the range of 1 mm or more and 2 mm or less. The height Ta of the coolant discharge groove 76 in the axial direction of the central axis 101 may be equal to or greater than the height of the gap 81 in the axial direction of the central axis 101, or may be less than the height of the gap 81 in the axial direction of the central axis 101.

When each of the wall portions 64u and 64v is extended radially outward from the central axis 101, the tip 42 of the cutter 41 is located between the extended surface of the wall portion 64u and the extended surface of the wall portion 64v.

The thickness Tb of the clamp bolt 51 (base 61) between the opposing surface 61a and the coolant discharge groove 76 (wall portion 64u) in the axial direction of the central axis 101 is greater than the thickness Tc between the coolant discharge groove 76 (wall portion 64v) and the bolt end face 61b in the axial direction of the central axis 101 (Tb>Tc).

In the tool 100 and clamp bolt 51 of this embodiment, the coolant discharge groove 76 has a groove shape that opens radially outward from the central axis 101 and circles around the central axis 101.

With this configuration, coolant can be discharged from the coolant discharge groove 76 toward the cutter 41 more evenly in the circumferential direction of the central axis 101 and at a large flow rate. This makes it possible to suppress the progression of wear on the cutting edge portion 47 of the cutter 41 and improve the life of the tool 100. In addition, by efficiently removing chips from between the cutter 41 and the workpiece, the machining accuracy of the workpiece can be improved.

In addition, in the tool 100 and clamp bolt 51 of this embodiment, a coolant passage 70 is provided in the base 61 through which coolant is introduced from the tool holder 20 and discharged toward the cutter 41.

With this configuration, the coolant passage 70 is not provided in the male thread portion 56, so the rigidity of the male thread portion 56 can be sufficiently ensured. This prevents damage to the male thread portion 56 and improves the life of the tool 100.

Furthermore, in this embodiment, the base 61 has a pair of wall portions 64, each of which is made of a plane perpendicular to the central axis 101, which face each other in the axial direction of the central axis 101 and form the groove walls of the coolant discharge groove 76.

With this configuration, the clamp bolt 51 rotates around the central axis 101 together with the tool holder 20, and centrifugal force acts on the coolant flowing through the coolant discharge groove 76 from the radially inner side to the radially outer side of the central axis 101. In this case, since each of the pair of wall portions 64 forming the groove wall of the coolant discharge groove 76 is made of a plane perpendicular to the central axis 101, the coolant that has flowed into the coolant discharge groove 76 from the multiple coolant introduction holes 71 can be directed more smoothly toward the second opening 77 of the coolant discharge groove 76 by the centrifugal force.

The base 61 also has an opposing surface 61a that faces the tool holder 20 in the axial direction of the central axis 101. The base 61 is provided with a plurality of coolant introduction holes 71 that open into the opposing surface 61a, through which the coolant supplied from the tool holder 20 is introduced and that communicate with the coolant discharge groove 76. The multiple coolant introduction holes 71 are spaced apart from one another in the circumferential direction of the central axis 101.

With this configuration, the coolant flowing through the multiple coolant introduction holes 71 flows into the coolant discharge groove 76 from positions spaced apart from each other in the circumferential direction of the central axis 101, thereby preventing variation in the amount of coolant flowing into the coolant discharge groove 76 in the circumferential direction of the central axis 101.

The clamp bolt 51 also includes a male threaded portion 56 that protrudes from the facing surface 61a in the axial direction of the central axis 101 and is screwed into the tool holder 20. The tool holder 20 has a holder end face 31a that faces the facing surface 61a in the axial direction of the central axis 101. Between the facing surface 61a and the holder end face 31a, a gap 81 is provided that runs around the male threaded portion 56 and through which coolant from the tool holder 20 flows.

With this configuration, the gap 81 provided between the opposing surface 61a and the holder end surface 31a functions as a space for temporarily storing the coolant introduced from the tool holder 20 to the multiple coolant introduction holes 71. This allows the coolant to be introduced more smoothly from the tool holder 20 to the multiple coolant introduction holes 71.

The base 61 also has an opposing surface 61a that faces the tool holder 20 and abuts against the cutter 41 in the axial direction of the central axis 101, and a bolt end surface 61b that faces the opposite side to the opposing surface 61a in the axial direction of the central axis 101. The clamp bolt 51 further includes a male thread portion 56 that protrudes from the opposing surface 61a in the axial direction of the central axis 101 and is screwed into the tool holder 20. A thickness Tb of the clamp bolt 51 between the opposing surface 61a and the coolant discharge groove 76 in the axial direction of the central axis 101 is greater than a thickness Tc of the clamp bolt 51 between the coolant discharge groove 76 and the bolt end surface 61b in the axial direction of the central axis 101.

With this configuration, the opposing surface 61a of the base 61 abuts against the cutter 41, and the clamp bolt 51 presses the cutter 41 against the tool holder 20 in the axial direction of the central axis 101. In this case, the above-mentioned relationship Tb>Tc ensures sufficient rigidity of the clamp bolt 51.

The cutter 41 is a skiving cutter. The coolant discharge groove 76 discharges coolant toward the tip 42 of the cutter 41 in the axial direction of the central axis 101 and in the radial direction of the central axis 101.

This configuration allows for efficient removal of chips from between the workpiece and the tip 42 of the cutter 41, which is the processing point of the skiving cutter.

Figure 6 is a cross-sectional view showing a modified example of the clamp bolt in Figure 1. Referring to Figure 6, in this modified example, the coolant discharge groove 76 is arranged parallel to a conical surface centered on the central axis 101. The coolant discharge groove 76 is inclined with respect to a plane perpendicular to the central axis 101. The coolant discharge groove 76 extends in the axial direction of the central axis 101, moving away from the opposing surface 61a as it moves from the radially inner side to the radially outer side of the central axis 101.

Instead of the head 57 in FIG. 1, the clamp bolt 51 has a hexagonal hole 58 into which a hexagonal wrench or the like can be inserted.

As shown in this modified example, the direction in which the coolant discharge groove 76 extends is not particularly limited as long as it is a direction approaching the radially outer side from the radially inner side of the central axis 101.

In FIG. 6, the clamp bolt 51 is provided so as to protrude in the axial direction of the central axis 101 beyond the tip 42 of the cutter 41, but in the present invention, the clamp bolt may be provided in a form that does not protrude from the tip of the cutter. Also, the fluid in the present invention is not limited to coolant, and may be, for example, air.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

20 tool holder, 21 holder body, 22 shank, 26 first shaft, 26a step surface, 27 key, 31 second shaft, 31a holder end surface, 31c, 61c outer circumferential surface, 32 coolant supply passage, 32p first coolant supply passage, 32q second coolant supply passage, 36 female thread, 41 cutter, 42 tip, 43 convex, 44 key groove, 46 fitting portion, 47 cutting edge, 51 clamp bolt, 56 male thread, 57 head, 58 hexagonal hole, 61 base, 61a opposing surface, 61b bolt end surface, 64, 64u, 64v wall, 70 coolant passage, 71 coolant introduction hole, 72 first opening, 76 coolant discharge groove, 77 second opening, 81 gap, 100 Tool, 101 Central axis.

Claims (4)

Cutter and
A tool holder;
a clamp bolt for fixing the cutter to the tool holder;
the clamp bolt includes a base portion extending in an axial direction of a rotation shaft of the tool holder and pressing the cutter against the tool holder in the axial direction of the rotation shaft,
the base is provided with a fluid discharge groove that opens radially outward from the rotation shaft and rotates around the rotation shaft, the fluid discharge groove discharging fluid supplied from the tool holder toward the cutter. A clamp bolt for fixing a cutter to a tool holder,
a base portion extending in an axial direction of a rotation shaft of the tool holder and pressing the cutter against the tool holder in the axial direction of the rotation shaft;
the base portion is provided with a fluid discharge groove that opens radially outward from the rotation shaft and rotates around the rotation shaft, the fluid discharge groove discharging fluid supplied from the tool holder toward the cutter. Cutter and
A tool holder;
a clamp bolt for fixing the cutter to the tool holder;
The clamp bolt is
a male thread portion extending on a rotation axis of the tool holder and screwed into the tool holder;
a base portion that protrudes radially outward from the rotating shaft beyond the male thread portion and extends in an axial direction of the rotating shaft to press the cutter against the tool holder in the axial direction of the rotating shaft,
the base portion has an opposing surface facing the tool holder in an axial direction of the rotation shaft,
The base portion is provided with a fluid passage that opens into the opposing surface, through which fluid supplied from the tool holder is introduced and through which fluid is discharged toward the cutter. A clamp bolt for fixing a cutter to a tool holder,
a male thread portion extending on a rotation axis of the tool holder and screwed into the tool holder;
a base portion that protrudes radially outward from the rotating shaft beyond the male thread portion and extends in an axial direction of the rotating shaft to press the cutter against the tool holder in the axial direction of the rotating shaft,
the base portion has an opposing surface facing the tool holder in an axial direction of the rotation shaft,
The base portion is provided with a fluid passage that opens to the opposing surface, through which fluid supplied from the tool holder is introduced and through which fluid is discharged toward the cutter.

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