Rotary cutting tool

Abstract

Provided is a large-diameter rotary cutting tool capable of supplying a coolant from the inside of a body part. A rotary cutting tool (100) is capable of rotating around a rotary shaft, and has a body part (1) and a cover (2) attached to the body part. The body part is provided with: a fitting part (16) into which a coolant is introduced and which is attached to a holder; a coolant reservoir groove (15) that is positioned farther to the outside in the radial direction than the fitting part; a first attachment hole (11) into which a bolt (41) for fixing the body part to the holder is inserted; and a coolant hole (14) that is continuous with the coolant reservoir groove and discharges the coolant.

Description

rotary cutting tools

[0001] The present disclosure relates to rotary cutting tools.

[0002] Japanese Patent Laid-Open Publication No. 2021-94680 (Patent Document 1) discloses a mounting member for a slotting cutter with a coolant hole. Japanese Patent Laid-Open Publication No. 2010-516483 (Patent Document 2) discloses a milling cutter assembly in which coolant is supplied to the milling cutter from a coolant supply source.

[0003] Japanese Patent Application Laid-Open No. 2021-94680 Special Publication No. 2010-516483

[0004] An object of the present disclosure is to provide a large diameter rotary cutting tool that can supply coolant from inside the body portion.

[0005] The rotary cutting tool according to the present disclosure is rotatable around a rotation axis and includes a main body and a cover attached to the main body. The main body includes a fitting portion into which coolant is introduced and which is attached to a holder, a coolant reservoir groove located radially outward of the fitting portion, a first mounting hole into which a bolt that secures the main body to the holder is inserted, and a coolant hole that is connected to the coolant reservoir groove and discharges the coolant. The cover includes a recess that sends coolant to the coolant reservoir groove. Let D1 be the maximum diameter of the main body, D2 be the outer diameter of the coolant reservoir groove, and R be the radial distance between the rotation axis and the center of the first mounting hole. When D1, D2, and R are expressed in millimeters, D1 satisfies Formula 1, D1 and D2 satisfy Formula 2, and R and D2 satisfy Formula 3.

[0006]

[0007]

[0008]

[0009] According to the present disclosure, it is possible to provide a large-diameter rotary cutting tool to which coolant can be supplied from inside the main body.

[0010] FIG. 1 is a first schematic perspective view showing the configuration of a rotary cutting tool according to this embodiment. FIG. 2 is an exploded schematic perspective view showing the configuration of a rotary cutting tool according to this embodiment. FIG. 3 is a second schematic perspective view showing the configuration of a rotary cutting tool according to this embodiment. FIG. 4 is a schematic plan view showing the configuration of a main body. FIG. 5 is a schematic plan view showing the configuration of a cover. FIG. 6 is a schematic plan view perspective view showing a state in which the cover is attached to the main body. FIG. 7 is a first schematic cross-sectional view showing a state in which a holder is attached to the rotary cutting tool. FIG. 8 is a second schematic cross-sectional view showing a state in which the holder is attached to the rotary cutting tool. FIG. 9 is a schematic perspective view showing a state in which a workpiece is being machined using the rotary cutting tool.

[0011] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure (also referred to as the present embodiments) will be listed and described.

[0012] (1) A rotary cutting tool according to the present disclosure is rotatable around a rotation axis and includes a main body and a cover attached to the main body. The main body includes a fitting portion through which coolant is introduced and which is attached to a holder, a coolant reservoir groove located radially outward of the fitting portion, a first mounting hole through which a bolt for securing the main body to the holder is inserted, and a coolant hole that is connected to the coolant reservoir groove and discharges the coolant. The cover includes a recess that directs coolant to the coolant reservoir groove. Let D1 be the maximum diameter of the main body, D2 be the outer diameter of the coolant reservoir groove, and R be the radial distance between the rotation axis and the center of the first mounting hole. If D1, D2, and R are all in millimeters, then D1 satisfies Equation 1, D1 and D2 satisfy Equation 2, and R and D2 satisfy Equation 3. This makes it possible to provide a large-diameter rotary cutting tool that can supply coolant from inside the main body.

[0013] (2) In the rotary cutting tool according to (1) above, where the inner diameter of the coolant hole is D3 and the length of the coolant hole as viewed along the rotation axis is L, and D3 and L are expressed in millimeters, D3 may satisfy Formula 4, and D3 and L may satisfy Formula 5. This can reduce breakage of the long drill when the long drill is used to form the coolant hole in the rotary cutting tool.

[0014]

[0015]

[0016] (3) In the rotary cutting tool according to (1) or (2), the recess may be cross-shaped when viewed along the rotation axis. This allows coolant to be evenly directed toward the coolant reservoir groove. The recess may be formed in the cover so as not to overlap with the first mounting hole through which the bolt is inserted.

[0017] (4) According to any one of the rotary cutting tools (1) to (3), the cover may be provided with a second mounting hole into which a screw for fixing the cover to the main body is inserted. The second mounting hole may be located radially inward of the coolant reservoir groove. This reduces coolant leakage from the gap between the main body and the cover, even when the coolant pressure is high. This allows coolant to be effectively supplied to the cutting insert during cutting. As a result, the life of the cutting insert can be extended.

[0018] (5) According to any one of the rotary cutting tools (1) to (4) above, the cover may be provided with a third mounting hole into which a screw for fixing the cover to the main body is inserted. The third mounting hole may be located radially outward of the coolant reservoir groove. This reduces coolant leakage from the gap between the main body and the cover, even when the coolant pressure is high. This allows coolant to be effectively supplied to the cutting insert during cutting. As a result, the life of the cutting insert can be extended.

[0019] Specific examples of rotary cutting tools according to embodiments of the present disclosure will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and descriptions thereof will not be repeated.

[0020] Fig. 1 is a first perspective schematic view showing the configuration of a rotary cutting tool 100 according to this embodiment. Fig. 2 is an exploded perspective schematic view showing the configuration of the rotary cutting tool 100 according to this embodiment.

[0021] As shown in Figures 1 and 2, the rotary cutting tool 100 according to this embodiment is a side cutter that can rotate around a rotation axis A. The rotary cutting tool 100 mainly includes a main body 1, a cover 2, a bolt 41, a cover setscrew 44, a cutting insert 4, and an insert fastening portion 3. The main body 1 has a first side surface 31, a second side surface 32, and an outer peripheral surface 33. The second side surface 32 is located opposite the first side surface 31. The outer peripheral surface 33 is continuous with each of the first side surface 31 and the second side surface 32. The outer peripheral surface 33 surrounds the rotation axis A. The cutting insert 4 is disposed on the outer peripheral surface 33.

[0022] As shown in Fig. 2, the main body 1 is provided with a fitting portion 16, a first mounting hole 11, a fifth mounting hole 12, and a sixth mounting hole 13. The fitting portion 16 is a portion that is attached to a holder 7, which will be described later. The fitting portion 16 is, for example, a spigot portion. The fitting portion 16 extends along the rotation axis A. The fitting portion 16 is a through hole. The fitting portion 16 opens to each of the first side surface 31 and the second side surface 32.

[0023] A cover placement groove 17 is provided in the first side surface 31. The cover placement groove 17 is composed of a bottom surface 17a and an inner peripheral surface 17b. The inner peripheral surface 17b is continuous with the bottom surface 17a. The fitting portion 16, the first mounting hole 11, the fifth mounting hole 12, and the sixth mounting hole 13 each open to the bottom surface 17a. The first mounting hole 11 is a through hole. The first mounting hole 11 opens to the second side surface 32. The fifth mounting hole 12 and the sixth mounting hole 13 are each holes with bottoms.

[0024] The cover 2 is attached to the main body 1. The cover 2 is placed in the cover placement groove 17. The cover 2 is provided with a second attachment hole 22, a third attachment hole 23, and a fourth attachment hole 21. Each of the second attachment hole 22, the third attachment hole 23, and the fourth attachment hole 21 is a through hole.

[0025] The first mounting hole 11 is positioned in the fourth mounting hole 21. A bolt 41 passes through each of the first mounting hole 11 and the fourth mounting hole 21. The cover locking screw 44 has an inner positioning screw 42 and an outer positioning screw 43. The second mounting hole 22 is positioned in the fifth mounting hole 12. The inner positioning screw 42 passes through the second mounting hole 22 and reaches the fifth mounting hole 12. The inner positioning screw 42 is fastened to the main body 1 at the fifth mounting hole 12.

[0026] The third mounting hole 23 is positioned in the sixth mounting hole 13. The outer mounting screw 43 passes through the third mounting hole 23 and reaches the sixth mounting hole 13. The outer mounting screw 43 is fastened to the main body 1 at the sixth mounting hole 13. The inner mounting screw 42 and the outer mounting screw 43 each secure the cover 2 to the main body 1.

[0027] Figure 3 is a second perspective schematic diagram showing the configuration of the rotary cutting tool 100 according to this embodiment. As shown in Figure 3, a protrusion 5 is provided on the second side surface 32 of the main body 1. The first mounting hole 11 opens into the protrusion 5. The protrusion 5 is provided with a groove 8 extending in the radial direction. The radial direction is the direction extending radially from the rotation axis A. The fitting portion 16 opens into the protrusion 5. The groove 8 is continuous with the fitting portion 16.

[0028] Fig. 4 is a schematic plan view showing the configuration of the main body 1. As shown in Fig. 4, a coolant reservoir groove 15 is provided in the main body 1. The coolant reservoir groove 15 is provided on the bottom surface 17a. The coolant reservoir groove 15 is located radially outward of the fitting portion 16. When viewed along the rotation axis A, the coolant reservoir groove 15 is, for example, annular. The coolant reservoir groove 15 surrounds the rotation axis A. The coolant reservoir groove 15 is not limited to being annular. The coolant reservoir groove 15 may be, for example, arc-shaped.

[0029] The bottom surface 17a is provided with first mounting holes 11, fifth mounting holes 12, and sixth mounting holes 13. The number of first mounting holes 11 is, for example, four. When viewed along the rotation axis A, the first mounting holes 11 are arranged at equal intervals along the rotation direction B of the rotary cutting tool 100. The number of fifth mounting holes 12 and sixth mounting holes 13 is, for example, eight. When viewed along the rotation axis A, the fifth mounting holes 12 and sixth mounting holes 13 are arranged at equal intervals along the rotation direction B of the rotary cutting tool 100.

[0030] In the radial direction, the fifth mounting hole 12 is located outside the fitting portion 16. In the radial direction, the fifth mounting hole 12 is located inside the coolant reservoir groove 15. In the radial direction, the center of the fifth mounting hole 12 is located outside the center of the first mounting hole 11.

[0031] In the radial direction, the sixth mounting hole 13 is located outside the fitting portion 16. In the radial direction, the sixth mounting hole 13 is located outside the coolant reservoir groove 15. In the radial direction, the center of the sixth mounting hole 13 is located outside the center of the first mounting hole 11.

[0032] As shown in Figure 4, the maximum diameter of the main body 1 is D1. The outer diameter of the coolant reservoir groove 15 is D2. The distance in the radial direction between the rotation axis A and the center of the first mounting hole 11 is R. The units of D1, D2, and R are mm. D1 satisfies Equation 1. D1 and D2 satisfy Equation 2. R and D2 satisfy Equation 3.

[0033]

[0034]

[0035]

[0036] D1 may be 200 mm or more, 250 mm or more, or 300 mm or more. D1 may be 650 mm or less, 600 mm or less, or 550 mm or less.

[0037] D2 may be 0.2 times or more, or 0.3 times or more, of D1. D2 may be 0.8 times or less, or 0.6 times or less, of D1. R is larger than the radius of the fitting portion 16. R is smaller than half the inner diameter of the coolant reservoir groove 15.

[0038] Fig. 5 is a schematic plan view showing the configuration of the cover 2. As shown in Fig. 5, the cover 2 has an opposing surface 25 that faces the main body 1. The diameter of the cover 2 is D4. D4 is smaller than D1 and larger than D2. A recess 24 is provided in the cover 2. The recess 24 opens to the opposing surface 25. The recess 24 does not open to the surface opposite the opposing surface 25. In other words, the recess 24 is a hole with a bottom.

[0039] As shown in Fig. 5, the recess 24 is, for example, cross-shaped when viewed along the rotation axis A. The recess 24 intersects with the rotation axis A. The recess 24 extends radially from the rotation axis A. The center of the cross-shaped recess 24 is located on the rotation axis A. The recess 24 is a flow path that sends coolant to the coolant reservoir groove 15. The shape of the recess 24 is not limited to a cross. The recess 24 may be, for example, linear.

[0040] 5 , the opposing surface 25 is provided with second mounting holes 22, third mounting holes 23, and fourth mounting holes 21. The number of each of the second mounting holes 22 and third mounting holes 23 is, for example, eight. When viewed along the rotation axis A, the second mounting holes 22 and the third mounting holes 23 are arranged at equal intervals along the rotation direction B of the rotary cutting tool 100. The number of the fourth mounting holes 21 is, for example, four. When viewed along the rotation axis A, the fourth mounting holes 21 are arranged at equal intervals along the rotation direction B of the rotary cutting tool 100.

[0041] 6 is a plan view perspective schematic diagram showing the state in which the cover 2 is attached to the main body 1. In the radial direction, the second mounting hole 22 and the fourth mounting hole 21 are each located inside the coolant reservoir groove 15. In the radial direction, the third mounting hole 23 is located outside the coolant reservoir groove 15.

[0042] 6 , when viewed along the rotation axis A, the recess 24 overlaps with each of the fitting portion 16 and the coolant reservoir groove 15. The first mounting hole 11, the second mounting hole 22, and the third mounting hole 23 overlap with the fourth mounting hole 21, the fifth mounting hole 12, and the sixth mounting hole 13, respectively. The first mounting hole 11, the second mounting hole 22, the third mounting hole 23, the fourth mounting hole 21, the fifth mounting hole 12, and the sixth mounting hole 13 do not overlap with the recess 24.

[0043] Coolant holes 14 are provided in the main body 1. The coolant holes 14 open to the outer peripheral surface 33 of the main body 1. The coolant holes 14 are connected to the coolant reservoir grooves 15. The coolant holes 14 extend from the coolant reservoir grooves 15 to the outer peripheral surface 33. Coolant is discharged from the coolant holes 14 to the outside. The number of coolant holes 14 is, for example, 10. When viewed along the rotation axis A, the openings of the coolant holes 14 on the outer peripheral surface 33 may be arranged at equal intervals in the rotation direction B.

[0044] The outer peripheral surface 33 is provided with an outer peripheral groove 33a, an insert placement groove 33b, and an outermost peripheral surface portion 33c. In the radial direction, the outer peripheral groove 33a is located more inward than the outermost peripheral surface portion 33c. The coolant hole 14 opens at the bottom of the outer peripheral groove 33a. The cutting insert 4 is placed in the insert placement groove 33b. The cutting insert 4 is attached to the outer peripheral surface 33 of the main body 1 using the insert fastening portion 3.

[0045] The inner diameter of the coolant hole 14 is defined as D3. The length of the coolant hole 14 as viewed in the direction along the rotation axis A is defined as L. The units of D3 and L are mm. D3 satisfies Equation 4. D3 and L satisfies Equation 5. The length of the coolant hole 14 is defined as the maximum length of the inner wall that constitutes the coolant hole 14.

[0046]

[0047]

[0048] D3 may be 1.2 mm or more, or 1.4 mm or more. D3 may be 2.8 mm or less, or 2.6 mm or less. L / D3 may be 12 or more, or 14 or more. L / D3 may be 28 or less, or 26 or less.

[0049] 7 is a first cross-sectional schematic view showing a state in which the holder 7 is attached to the rotary cutting tool 100. The first cross section is a plane that is parallel to the rotation axis A, does not include the rotation axis A, and intersects the two bolts 41.

[0050] As shown in Fig. 7, the retainer 7 has a bolt insertion hole 9. The bolt 41 is fastened to the retainer 7 through the bolt insertion hole 9. The bolt 41 fixes the main body 1 to the retainer 7. The bolt 41 is inserted into the first mounting hole 11. The bolt 41 passes through the first mounting hole 11 and reaches the bolt insertion hole 9.

[0051] 8 is a second cross-sectional schematic view showing a state in which the holder 7 is attached to the rotary cutting tool 100. The second cross section is parallel to the rotation axis A and is a plane including the rotation axis A.

[0052] As shown in FIG. 8 , the holder 7 has a first region 7a and a second region 7b. The second region 7b is continuous with the first region 7a. The outer diameter of the first region 7a is larger than the outer diameter of the second region 7b. The second region 7b protrudes from the end face of the first region 7a. The second region 7b is inserted into the fitting portion 16. The front end face of the first region 7a may contact the protruding portion 5. The outer peripheral surface of the second region 7b may contact the inner peripheral surface of the protruding portion 5. The holder 7 is provided with a coolant introduction hole 7c. The coolant introduction hole 7c penetrates both the first region 7a and the second region 7b.

[0053] The arrows in Figure 8 indicate the flow of coolant. The coolant is introduced into the coolant introduction hole 7c provided in the holder 7. The coolant is introduced from the holder 7 into the fitting portion 16 of the main body 1. After passing through the fitting portion 16, the coolant flows toward the recess 24 provided in the cover 2. The coolant flows through the recess 24 toward the coolant reservoir groove 15. The coolant flows through the coolant reservoir groove 15 toward the coolant hole 14. The coolant is released to the outside of the main body 1 through the coolant hole 14.

[0054] FIG. 9 is a perspective schematic view showing a state in which a workpiece is being machined using the rotary cutting tool 100.

[0055] As shown in FIG. 9 , the rotary cutting tool 100 is attached to a holder 7. The holder 7 is, for example, an arbor. A plurality of cutting inserts 4 are attached to the outer peripheral surface 33 of the main body 1 of the rotary cutting tool 100. As the holder 7 rotates, the rotary cutting tool 100 rotates around a rotation axis A. The rotary cutting tool 100 is movable along a plane perpendicular to the rotation axis A while rotating around the rotation axis A. A workpiece 60 is cut by the cutting inserts 4. During cutting, coolant is released from coolant holes 14 provided in the main body 1 toward the cutting inserts 4.

[0056] Next, the effects of the rotary cutting tool 100 according to this embodiment will be described. With the rotary cutting tool 100 according to this embodiment, where D1 is the maximum diameter of the main body 1, D2 is the outer diameter of the coolant reservoir groove 15, and R is the radial distance between the rotation axis A and the center of the first mounting hole 11, and D1, D2, and R are all expressed in millimeters, D1 satisfies Formula 1, D1 and D2 satisfy Formula 2, and R and D2 satisfy Formula 3. This makes it possible to provide a large-diameter rotary cutting tool 100 capable of supplying coolant from inside the main body 1. Specifically, by making D2 and R satisfy Formula 3, the coolant reservoir groove 15 can be formed outside the first mounting hole 11. Furthermore, by making D1 satisfy Formula 1 and making D1 and D2 satisfy Formula 2, when a long drill is used to form the coolant hole 14 in the main body 1, the long drill can be prevented from breaking.

[0057] According to the rotary cutting tool 100 of this embodiment, when the inner diameter of the coolant hole 14 is D3 and the length of the coolant hole 14 as viewed along the rotation axis A is L, and the units of D3 and L are mm, D3 may satisfy Formula 4, and D3 and L may also satisfy Formula 5. This makes it possible to reduce breakage of the long drill when forming the coolant hole 14 in the rotary cutting tool 100 using the long drill.

[0058] According to the rotary cutting tool 100 of this embodiment, the recess 24 may be cross-shaped when viewed along the rotation axis A. This allows the coolant to be evenly sent toward the coolant reservoir groove 15. Furthermore, the recess 24 can be formed in the cover 2 so as not to overlap with the first mounting hole 11 into which the bolt 41 is inserted.

[0059] According to the rotary cutting tool 100 of this embodiment, the second mounting hole 22 may be located radially inward of the coolant reservoir groove 15. This reduces the risk of coolant leaking from the gap between the main body 1 and the cover 2, even when the coolant pressure is high (e.g., 7 MPa or more and 10 MPa or less). This allows the coolant to be effectively supplied to the cutting insert 4 during cutting. As a result, the life of the cutting insert 4 can be extended.

[0060] According to the rotary cutting tool 100 of this embodiment, the third mounting hole 23 may be located radially outward of the coolant reservoir groove 15. This reduces the leakage of coolant from the gap between the main body 1 and the cover 2 even when the coolant pressure is high (e.g., 7 MPa or more and 10 MPa or less). This allows the coolant to be effectively supplied to the cutting insert 4 during cutting. As a result, the life of the cutting insert 4 can be extended.

[0061] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the above-described embodiments, and is intended to include meanings equivalent to the claims and all modifications within the scope thereof.

[0062] 1 Main body portion, 2 Cover, 3 Insert fastening portion, 4 Cutting insert, 5 Protrusion portion, 7 Holder, 7a First region, 7b Second region, 7c Coolant introduction hole, 8 Groove portion, 9 Bolt insertion hole, 11 First mounting hole, 12 Fifth mounting hole, 13 Sixth mounting hole, 14 Coolant hole, 15 Coolant reservoir groove, 16 Fitting portion, 17 Cover placement groove, 17a Bottom surface, 17b Inner peripheral surface, 21 Fourth mounting hole, 22 Second mounting hole, 23 Third mounting hole, 24 Recess, 25 Opposing surface, 31 First side surface, 32 Second side surface, 33 Outer peripheral surface, 33a Outer peripheral groove, 33b Insert placement groove, 33c Outermost peripheral surface portion, 41 Bolt, 42 Inner placement screw, 43 Outer placement screw, 44 Cover fixing screw, 60 Workpiece, 100 Rotary cutting tool, A A axis of rotation, B direction of rotation.

Claims

1. A rotary cutting tool rotatable about a rotation axis, comprising a main body portion and a cover attached to the main body portion, wherein in the main body portion, there are provided a fitting portion into which a coolant is introduced and which is attached to a holder, a coolant reservoir groove located radially outside the fitting portion, a first attachment hole into which a bolt for fixing the main body portion to the holder is inserted, and a coolant hole that is continuous with the coolant reservoir groove and discharges the coolant; in the cover, there is provided a recess for sending the coolant to the coolant reservoir groove; when the maximum diameter of the main body portion is D1, the outer diameter of the coolant reservoir groove is D2, and the distance between the rotation axis and the center of the first attachment hole in the radial direction is R, with the units of D1, D2, and R being mm, D1 satisfies Equation 1, D1 and D2 satisfy Equation 2, and R and D2 satisfy Equation 3, the rotary cutting tool.

2. In the case where the inner diameter of the coolant hole is D3, the length of the coolant hole as viewed along the rotation axis is L, and the units of D3 and L are mm, D3 satisfies Equation 4, and D3 and L satisfy Equation 5. The rotary cutting tool according to claim 1.

3. The rotary cutting tool according to claim 1 or 2, wherein, when viewed along the rotation axis, the concave portion has a cross shape.

4. In the cover, a second mounting hole into which a screw for fixing the cover to the main body portion is inserted is provided, and in the radial direction, the second mounting hole is located inside the coolant reservoir groove. The rotary cutting tool according to any one of claims 1 to 3.

5. In the cover, a third mounting hole into which a screw for fixing the cover to the main body portion is inserted is provided, and in the radial direction, the third mounting hole is located outside the coolant reservoir groove. The rotary cutting tool according to any one of claims 1 to 4.

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