WO2024190028A1

WO2024190028A1 - Tool

Info

Publication number: WO2024190028A1
Application number: PCT/JP2023/045228
Authority: WO
Inventors: Makoto Muraoka
Original assignee: DMG Mori Co Ltd
Current assignee: DMG Mori Co Ltd
Priority date: 2023-03-15
Filing date: 2023-12-18
Publication date: 2024-09-19
Anticipated expiration: 2025-09-15
Also published as: EP4598703A1; JP2024132821A

Abstract

A tool includes 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) includes: a male thread portion (56) screwed into the tool holder (20); and a base portion (61) that protrudes outward in a radial direction of a rotation axis of the tool holder (20) beyond the male thread portion (56), extends in an axial direction of the rotation axis of the tool holder (20), and presses the cutter (41) against the tool holder (20) in the axial direction of the rotation axis of the tool holder (20). The base portion (61) has a facing surface (61a) that faces the tool holder (20) in the axial direction of the rotation axis of the tool holder (20). The base portion (61) is provided with a coolant path (70) having an opening at the facing surface (61a), and, via the opening, coolant supplied from the tool holder (20) is introduced into the coolant path (70) and discharged through the coolant path (70) toward the cutter (41).

Description

TOOL

The present invention relates to a tool.

For example, Japanese Patent Laying-Open No. 2004-276136 (PTL 1) discloses a fastening bolt used for fastening a front milling cutter attached to a lower end portion of an arbor. The fastening bolt has: a male thread portion that is screwed into a female thread portion of the arbor; and a body portion that presses a bottom surface portion of the front milling cutter.

The fastening bolt has an internal flow path provided inside the bolt. The internal flow path provided inside the bolt is formed of: a main flow path extending along the axial center of the male thread portion and through which cutting oil supplied from the arbor flows down; and a plurality of branch flow paths provided to branch from an end of the main flow path and inclined downward toward an outer circumferential surface of the body portion, and the cutting oil is discharged through the plurality of branch flow paths toward a throwaway tip of the front milling cutter.

PTL 1: Japanese Patent Laying-Open No. 2004-276136

In the fastening bolt disclosed in the above-mentioned PTL 1, cutting oil is discharged toward a machining point of a workpiece through openings of the plurality of branch flow paths. However, the cutting oil may not be sufficiently discharged due to the flow path resistance in each of the branch flow paths, or the amount of the cutting oil supplied to the machining point of the workpiece may vary since the plurality of branch flow paths open at intervals in the rotation direction (the circumferential direction) of the front milling cutter. In these cases, the effect of suppressing the wear of the tool by supplying the cutting oil cannot be sufficiently achieved, which causes a concern that the tool life may become short.

Further, in the fastening bolt disclosed in the above-mentioned PTL 1, the main flow path of the internal flow path provided inside the bolt is provided in the male thread portion that is screwed into the arbor. In such a configuration, the rigidity of the male thread portion cannot be sufficiently ensured, which causes a concern that the tool life may become short due to breakage of the male thread portion.

Thus, an object of the present invention is to solve the above-described problems and to provide a tool improved in 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 portion. The base portion extends in an axial direction of a rotation axis of the tool holder and presses the cutter against the tool holder in the axial direction of the rotation axis. The base portion is provided with a fluid discharge groove through which fluid supplied from the tool holder is discharged toward the cutter. The fluid discharge groove has a groove shape that opens to an outer side in a radial direction of the rotation axis and extends around the rotation axis.

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 includes a base portion. The base portion extends in an axial direction of a rotation axis of the tool holder and presses the cutter against the tool holder in the axial direction of the rotation axis. The base portion is provided with a fluid discharge groove through which fluid supplied from the tool holder is discharged toward the cutter. The fluid discharge groove has a groove shape that opens to an outer side in a radial direction of the rotation axis and extends around the rotation axis.

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 thread portion and a base portion. The male thread portion extends on a rotation axis of the tool holder and is screwed into the tool holder. The base portion protrudes outward in a radial direction of the rotation axis beyond the male thread portion, extends in an axial direction of the rotation axis, and presses the cutter against the tool holder in the axial direction of the rotation axis. The base portion has a facing surface. The facing surface faces the tool holder in the axial direction of the rotation axis. The base portion is provided with a fluid path. The fluid path has an opening at the facing surface, and, via the opening, fluid supplied from the tool holder is introduced into the fluid path and discharged through the fluid path 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 includes a male thread portion and a base portion. The male thread portion extends on a rotation axis of the tool holder and is screwed into the tool holder. The base portion protrudes outward in a radial direction of the rotation axis beyond the male thread portion, extends in an axial direction of the rotation axis, and presses the cutter against the tool holder in the axial direction of the rotation axis. The base portion has a facing surface. The facing surface faces the tool holder in the axial direction of the rotation axis. The base portion is provided with a fluid path. The fluid path has an opening at the facing surface, and, via the opening, fluid supplied from the tool holder is introduced into the fluid path and discharged through the fluid path toward the cutter.

According to the present invention, a tool improved in tool life can be provided.

Fig. 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. 3 is a side view showing a clamp bolt in Fig. 1. Fig. 4 is a perspective view showing the clamp bolt in Fig. 1. Fig. 5 is an enlarged cross-sectional view of a region surrounded by a two-dot-dash line V in Fig. 1. Fig. 6 is a cross-sectional view showing a modification of the clamp bolt shown in Fig. 1.

Embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings referred to below, the same or corresponding members are denoted by the same reference characters.

Fig. 1 is a partial cross-sectional view showing a tool according to an embodiment of the present invention. Fig. 1 shows an external appearance of a tool holder 20 described later and cross sections of a cutter 41 and a clamp bolt 51, each of which is described later.

Referring to Fig. 1, a tool 100 according to the present embodiment is used for machining a workpiece. Tool 100 is attached to a spindle of a machine tool such as a machining center or a combined processing machine, and rotates around a central axis 101 to machine a workpiece.

First, the overall structure of tool 100 will be described. Tool 100 includes a tool holder 20, a cutter 41, and a clamp bolt 51. Tool holder 20 is configured to hold cutter 41 and to be attachable to and detachable from the spindle of the machine tool. Cutter 41 comes into contact with a workpiece to be machined and machines the workpiece. Cutter 41 is held by tool holder 20. Clamp bolt 51 is a fastener for fixing cutter 41 to tool holder 20.

During machining of the workpiece, the rotational motion from the spindle of the machine tool is transmitted to tool 100 through tool holder 20. Tool holder 20, cutter 41, and clamp bolt 51 integrally rotate around central axis 101. Central axis 101 corresponds to the rotation axis of tool 100. Central axis 101 corresponds to the rotation axis of each of tool holder 20, cutter 41, and clamp bolt 51.

Fig. 2 is a perspective view showing the tool holder in Fig. 1. Referring to Fig. 2, tool holder 20 includes a holder body portion 21 and a shank portion 22. Holder body portion 21 and shank portion 22 extend around central axis 101.

Holder body portion 21 holds cutter 41. Shank portion 22 is fixed to the spindle of the machine tool or gripped by an arm in an automatic tool changer (ATC) of the machine tool. The specifications of shank portion 22 comply with CAPTO. The specifications of shank portion 22 are not particularly limited and may comply, for example, with BT or HSK.

Holder body portion 21 extends in a cylindrical shape around central axis 101. An end portion of holder body portion 21 in the axial direction of central axis 101 is connected to shank portion 22.

Holder body portion 21 has a first shaft portion 26 and a second shaft portion 31. First shaft portion 26 and second shaft portion 31 are connected contiguously to each other in the axial direction of central axis 101. The diameter of first shaft portion 26 around central axis 101 is larger than the diameter of second shaft portion 31 around central axis 101. First shaft portion 26 is connected to shank portion 22. First shaft portion 26 has a stepped surface 26a. Stepped surface 26a is a flat plane orthogonal to central axis 101. Second shaft portion 31 protrudes from stepped surface 26a in the axial direction of central axis 101. Stepped surface 26a extends in a ring shape around second shaft portion 31.

First shaft portion 26 is provided with a plurality of keys 27. Each key 27 is provided to protrude from stepped surface 26a at a distance from second shaft portion 31 outward in the radial direction of central axis 101. The plurality of keys 27 are spaced apart from each other in the circumferential direction of central axis 101.

Tool holder 20 has a holder end surface 31a. Holder end surface 31a is a flat plane orthogonal to central axis 101. Holder end surface 31a is provided at an end portion of tool holder 20 (holder body portion 21) in the axial direction of central axis 101. Holder end surface 31a corresponds to an end surface of second shaft portion 31 that is located at a tip end protruding from stepped surface 26a. Holder end surface 31a extends in a ring shape around an opening of a female thread portion 36 described later.

Tool holder 20 is provided with female thread portion 36. Female thread portion 36 is provided on the inner circumferential surface of holder body portion 21. Female thread portion 36 extends around central axis 101 and opens at holder end surface 31a.

Tool holder 20 is further provided with a first coolant supply path 32p and a second coolant supply path 32q. First coolant supply path 32p and second coolant supply path 32q are provided in holder body portion 21.

First coolant supply path 32p and second coolant supply path 32q are provided in second shaft portion 31. Second coolant supply path 32q has a groove shape that is recessed from an outer circumferential surface 31c of second shaft portion 31, extends in the axial direction of central axis 101, and opens at holder end surface 31a. First coolant supply path 32p extends in the radial direction of central axis 101. First coolant supply path 32p communicates with the space inside second shaft portion 31 at an inner end portion in the radial direction of central axis 101, and communicates with second coolant supply path 32q at an outer end portion in the radial direction of central axis 101.

First coolant supply path 32p and second coolant supply path 32q are paired to form a coolant supply path 32. A plurality of coolant supply paths 32 are spaced apart from each other in the circumferential direction of central axis 101. These coolant supply paths 32 are provided at regular intervals in the circumferential direction of central axis 101.

During machining of the workpiece by tool 100, coolant is supplied from the spindle of the machine tool into the space inside tool holder 20. As indicated by dotted-line arrows in Fig. 2, the coolant supplied into the space inside tool holder 20 flows through first coolant supply path 32p and second coolant supply path 32q in this order and is then supplied toward clamp bolt 51.

Referring to Fig. 1, cutter 41 includes a fitting portion 46. Fitting portion 46 extends in a cylindrical shape around central axis 101. Fitting portion 46 is fitted on the outer circumference of second shaft portion 31. Fitting portion 46 is in contact with stepped surface 26a in the axial direction of central axis 101. Second coolant supply path 32q is covered by fitting portion 46 on the outer side in the radial direction of central axis 101.

Fitting portion 46 is provided with a plurality of key grooves 44. A plurality of keys 27 on the tool holder 20 side are respectively inserted into the plurality of key grooves 44. The structure in which keys 27 are fitted in key grooves 44 functions to stop rotation of cutter 41 relative to tool holder 20.

Fitting portion 46 has a protruding portion 43. Protruding portion 43 has a protruding shape protruding from fitting portion 46 in the axial direction of central axis 101. Protruding portion 43 is provided on the inner side of a cutting edge portion 47 (described later) in the radial direction of central axis 101.

Cutter 41 further includes cutting edge portion 47. Cutting edge portion 47 has a shape of a cutting edge for machining a workpiece. Cutting edge portion 47 protrudes from fitting portion 46 in the axial direction of central axis 101.

In the present embodiment, cutter 41 is a skiving cutter for machining a gear on a workpiece. Cutter 41 is integrally formed of metal such as high-speed steel (HSS) or cemented carbide. While the workpiece and tool 100 are rotated in synchronization with each other, a tip end portion 42 of cutter 41 (cutting edge portion 47) in the axial direction of central axis 101 and in the radial direction of central axis 101 is brought into contact with the workpiece to thereby form gear teeth on the outer circumferential surface or the inner circumferential 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 a plurality of throwaway tips are detachably attached.

Fig. 3 is a side view showing the clamp bolt in Fig. 1. Fig. 4 is a perspective view showing the clamp bolt in Fig. 1. Fig. 5 is an enlarged cross-sectional view of a region surrounded by a two-dot-dash line V in Fig. 1.

Referring to Figs. 1 to 5, clamp bolt 51 is integrally formed of metal. Clamp bolt 51 includes a base portion 61, a male thread portion 56, and a head portion 57.

Male thread portion 56 is connected to tool holder 20. Male thread portion 56 extends axially on central axis 101. Male thread portion 56 is formed of a solid shaft body. Male thread portion 56 is screwed into female thread portion 36 of tool holder 20.

Base portion 61 extends around central axis 101. Base portion 61 protrudes outward in the radial direction of central axis 101 beyond male thread portion 56. The diameter of base portion 61 around central axis 101 is larger than the diameter of male thread portion 56 around central axis 101. Base portion 61 is disposed inside cutting edge portion 47 of cutter 41.

Base portion 61 has a facing surface 61a and a bolt end surface 61b. Each of facing surface 61a and bolt end surface 61b is a flat plane orthogonal to central axis 101. Bolt end surface 61b faces away from facing surface 61a in the axial direction of central axis 101.

Facing surface 61a faces holder end surface 31a of tool holder 20 in the axial direction of central axis 101. Facing surface 61a is in contact with protruding portion 43 of cutter 41 in the axial direction of central axis 101. With the fastening force of male thread portion 56 on female thread portion 36, base portion 61 presses cutter 41 (fitting portion 46) against tool holder 20 in the axial direction of central axis 101. Fitting portion 46 is sandwiched between stepped surface 26a and facing surface 61a in the axial direction of central axis 101, and thereby, cutter 41 is fixed to tool holder 20.

A gap 81 is provided between facing surface 61a and holder end surface 31a. Gap 81 is a space having a fixed height in the axial direction of central axis 101 and extending in a ring shape around central axis 101. Gap 81 is defined between male thread portion 56 and protruding portion 43 in the radial direction of central axis 101. Second coolant supply path 32q communicates with gap 81. By way of example, the height of gap 81 in the axial direction of central axis 101 is in the range of 0.5 mm or more and 1.5 mm or less.

Head portion 57 is provided axially on central axis 101. Head portion 57 protrudes from bolt end surface 61b in the axial direction of central axis 101. When viewed in the axial direction of central axis 101, head portion 57 has a hexagonal shape such that a spanner or the like can be hooked over head portion 57.

The following describes the structure of clamp bolt 51 with which the coolant supplied from tool holder 20 is discharged toward cutter 41.

Referring to Figs. 1 to 5, base portion 61 is provided with a coolant path 70. Coolant path 70 has a plurality of first openings 72 and a second opening 77. Coolant path 70 extends between the plurality of first openings 72 and second opening 77. Each first opening 72 serves as an inlet port of coolant that flows from tool holder 20 to clamp bolt 51. Second opening 77 serves as a discharge port of coolant that flows from clamp bolt 51 to cutter 41.

The plurality of first openings 72 open at facing surface 61a. Each first opening 72 has a circular opening shape. The plurality of first openings 72 are spaced apart from each other in the circumferential direction of central axis 101. Coolant path 70 communicates with gap 81 through the plurality of first openings 72.

Second opening 77 opens at an outer circumferential surface 61c of base portion 61. Second opening 77 is located between facing surface 61a and bolt end surface 61b in the axial direction of central axis 101. Second opening 77 has a band-like opening shape having a fixed height in the axial direction of central axis 101 and extending around central axis 101 by 360°.

Coolant path 70 includes a plurality of coolant introduction holes 71 and a coolant discharge groove 76. Coolant supplied from tool holder 20 is introduced into coolant introduction hole 71. Through coolant discharge groove 76, the coolant having flowed in via coolant introduction hole 71 is discharged toward cutter 41.

The plurality of coolant introduction holes 71 respectively have a plurality of first openings 72. Each coolant introduction hole 71 extends from the corresponding first opening 72 in the direction away from facing surface 61a in the axial direction of central axis 101 and is connected at its distal end to coolant discharge groove 76. The plurality of coolant introduction holes 71 are spaced apart from each other in the circumferential direction of central axis 101. The plurality of coolant introduction holes 71 are provided at regular intervals in the circumferential direction of central axis 101.

Coolant introduction hole 71 extends obliquely with respect to central axis 101. Coolant introduction hole 71 extends to incline from the inner side toward the outer side in the radial direction of central axis 101 as it extends from first opening 72 toward coolant discharge groove 76.

Note that the configuration of coolant introduction hole 71 is not limited to the above, but may extend in parallel to central axis 101 or may extend to incline in the rotation direction of tool 100 or in the direction opposite to the rotation direction of tool 100 as it extends from first opening 72 toward coolant discharge groove 76.

Coolant discharge groove 76 has second opening 77. Coolant discharge groove 76 has a groove shape that opens at second opening 77 toward the outer side in the radial direction of central axis 101 and extends around central axis 101.

Coolant discharge groove 76 is provided in parallel to a flat plane orthogonal to central axis 101. Coolant discharge groove 76 defines a ring-shaped space having a fixed height in the axial direction of central axis 101 and extending around central axis 101 by 360°.

Base portion 61 has a pair of wall portions 64 (64u, 64v) each forming a groove wall of coolant discharge groove 76. Each wall portion 64 is a flat plane orthogonal to central axis 101. The pair of wall portions 64 face each other in the axial direction of central axis 101. Coolant introduction hole 71 opens at wall portion 64u.

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

In the case where each of

wall portions

64u and 64v is extended outward in the radial direction of central axis 101, tip end portion 42 of cutter 41 is located between the extended surface of wall portion 64u and the extended surface of wall portion 64v.

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

In tool 100 and clamp bolt 51 according to the present embodiment, coolant discharge groove 76 has a groove shape that opens to the outer side in the radial direction of central axis 101 and extends around central axis 101.

According to the configuration as described above, the coolant can be discharged from coolant discharge groove 76 toward cutter 41 at a high flow rate and more uniformly in the circumferential direction of central axis 101. Thereby, the progress of wear of cutting edge portion 47 in cutter 41 can be suppressed, so that tool 100 can be improved in life length. In addition, by efficiently removing swarf from between cutter 41 and the workpiece, the machining accuracy for the workpiece can be improved.

Further, in tool 100 and clamp bolt 51 in the present embodiment, base portion 61 is provided with coolant path 70 through which the coolant is introduced from tool holder 20 and discharged toward cutter 41.

According to the configuration as described above, coolant path 70 is not provided in male thread portion 56, and thus, the rigidity of male thread portion 56 can be sufficiently ensured. Thereby, breakage of male thread portion 56 can be prevented, and tool 100 can be improved in life length.

Further, in the present embodiment, base portion 61 includes a pair of wall portions 64 facing each other in the axial direction of central axis 101, the pair of wall portions 64 each being a flat plane orthogonal to central axis 101 and each forming a groove wall of coolant discharge groove 76.

According to the configuration as described above, clamp bolt 51 rotates integrally with tool holder 20 around central axis 101, and thereby, centrifugal force acting from the inner side to the outer side in the radial direction of central axis 101 is applied to the coolant flowing through coolant discharge groove 76. In this case, each of the pair of wall portions 64 each forming the groove wall of coolant discharge groove 76 is a flat plane orthogonal to central axis 101, and therefore, the coolant having flowed into coolant discharge groove 76 via the plurality of coolant introduction holes 71 can be more smoothly directed by the centrifugal force toward second opening 77 of coolant discharge groove 76.

Base portion 61 has facing surface 61a that faces tool holder 20 in the axial direction of central axis 101. Base portion 61 is provided with a plurality of coolant introduction holes 71 each having an opening at facing surface 61a and communicating with coolant discharge groove 76, and the coolant supplied from tool holder 20 is introduced into base portion 61 via each opening. The plurality of coolant introduction holes 71 are spaced apart from each other in the circumferential direction of central axis 101.

According to the configuration as described above, the coolant flowing through each of the plurality of coolant introduction holes 71 flows into coolant discharge groove 76 from a corresponding one of the positions spaced apart from each other in the circumferential direction of central axis 101, which makes it possible to suppress variations in the amount of coolant flowing into coolant discharge groove 76 in the circumferential direction of central axis 101.

Further, clamp bolt 51 includes male thread portion 56 that protrudes from facing surface 61a in the axial direction of central axis 101 and that is screwed into tool holder 20. Tool holder 20 has a holder end surface 31a that faces facing surface 61a in the axial direction of central axis 101. Gap 81 extending around male thread portion 56 is provided between facing surface 61a and holder end surface 31a, and the coolant from tool holder 20 flows into gap 81.

According to the configuration as described above, gap 81 provided between facing surface 61a and holder end surface 31a functions as a space in which the coolant to be introduced from tool holder 20 into the plurality of coolant introduction holes 71 is temporarily stored. Thus, the coolant can be more smoothly introduced from tool holder 20 into the plurality of coolant introduction holes 71.

Further, base portion 61 has: facing surface 61a that faces tool holder 20 and is in contact with cutter 41 in the axial direction of central axis 101; and bolt end surface 61b that faces away from facing surface 61a in the axial direction of central axis 101. Clamp bolt 51 further includes male thread portion 56 that protrudes from facing surface 61a in the axial direction of central axis 101 and is screwed into tool holder 20. Thickness Tb of clamp bolt 51 between facing surface 61a and coolant discharge groove 76 in the axial direction of central axis 101 is larger than thickness Tc of clamp bolt 51 between coolant discharge groove 76 and bolt end surface 61b in the axial direction of central axis 101.

According to the configuration as described above, when facing surface 61a of base portion 61 is in contact with cutter 41, clamp bolt 51 presses cutter 41 against tool holder 20 in the axial direction of central axis 101. In this case, the rigidity of clamp bolt 51 can be sufficiently ensured by the above-mentioned relation of Tb > Tc.

Cutter 41 is a skiving cutter. Through coolant discharge groove 76, coolant is discharged toward tip end portion 42 of cutter 41 in the axial direction of central axis 101 and in the radial direction of central axis 101.

According to the configuration as described above, swarf can be efficiently removed from between the workpiece and tip end portion 42 of cutter 41 that serves as a machining point in the skiving cutter.

Fig. 6 is a cross-sectional view showing a modification of the clamp bolt shown in Fig. 1. Referring to Fig. 6, in the present modification, coolant discharge groove 76 is located in parallel to a conical surface centered on central axis 101. Coolant discharge groove 76 is inclined with respect to a plane orthogonal to central axis 101. Coolant discharge groove 76 extends away from facing surface 61a in the axial direction of central axis 101 as it extends from the inner side to the outer side in the radial direction of central axis 101.

In place of head portion 57 in Fig. 1, clamp bolt 51 is provided with a hexagonal hole 58 into which a hexagonal wrench or the like can be inserted.

As shown in the present modification, the direction in which coolant discharge groove 76 extends is not particularly limited as long as it is directed from the inner side to the outer side in the radial direction of central axis 101.

In Fig. 6, clamp bolt 51 is provided to protrude in the axial direction of central axis 101 beyond tip end portion 42 of cutter 41, but in the present invention, clamp bolt 51 may be provided so as not to protrude beyond the tip end portion of cutter 41. The fluid in the present invention is not limited to coolant but may be air, for example.

It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the meaning and scope equivalent to the terms of the claims.

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

Claims

A tool comprising:
a cutter;
a tool holder; and
a clamp bolt for fixing the cutter to the tool holder, wherein
the clamp bolt includes
a male thread portion extending on a rotation axis of the tool holder and screwed into the tool holder, and
a base portion protruding outward in a radial direction of the rotation axis beyond the male thread portion and extending in an axial direction of the rotation axis, the base portion pressing the cutter against the tool holder in the axial direction of the rotation axis,
the base portion has a facing surface that faces the tool holder in the axial direction of the rotation axis, and
the base portion is provided with a fluid path having an opening at the facing surface, and, via the opening, fluid supplied from the tool holder is introduced into the fluid path and discharged through the fluid path toward the cutter.
The tool according to claim 1, wherein the fluid path includes a fluid discharge groove having a groove shape that opens to an outer side in the radial direction of the rotation axis, the groove shape extending around the rotation axis, and fluid being discharged through the fluid discharge groove toward the cutter.
The tool according to claim 2, wherein the base portion has a pair of wall portions facing each other in the axial direction of the rotation axis, the pair of wall portions each being a flat plane orthogonal to the rotation axis and each forming a groove wall of the fluid discharge groove.
The tool according to claim 2, wherein
the base portion further has a bolt end surface that faces away from the facing surface in the axial direction of the rotation axis, and
a thickness of the base portion between the facing surface and the fluid discharge groove in the axial direction of the rotation axis is larger than a thickness of the base portion between the fluid discharge groove and the bolt end surface in the axial direction of the rotation axis.
The tool according to claim 1, wherein
the tool holder has a holder end surface that faces the facing surface in the axial direction of the rotation axis, and
a gap extending around the male thread portion is provided between the facing surface and the holder end surface, and fluid from the tool holder flows into the gap.