Fastening component

Abstract

To provide a fastening component which enables a fluid to be sprayed evenly to a cut portion while inhibiting complication of the structure and reducing the number of components.SOLUTION: A fastening component 100 is fastened to an arbor 10, fixes a cutter 20 serving as a rotary cutting tool to the arbor 10, and includes: a shaft part 30 screwed into a female screw 13c of the arbor 10; an engagement hole 40 formed at a shaft center on an end surface opposite to the side fastened to the arbor 10; a first flow path 50 which is formed at a shaft center AX of the shaft part 30 and open on an end surface at the side fastened to the arbor 10 of the shaft part 30; a third flow path 70 which is open at a position away from the shaft center at an end opposite to the side fastened to the arbor 10; and a second flow path 60 connecting the first flow path 50 and the third flow path 70.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to fastening parts.

Background Art

[0002] It is known to form a flow path in a fastening part that fixes a rotary cutting tool such as a face mill, shell end mill, boring cutter, side cutter, etc. to an arbor, and supply coolant to a cutting location by the rotary cutting tool through this flow path (see Patent Documents 1 to 4).

[0003] For example, Patent Document 1 shows a bolt having a groove that opens at an end face on the outer periphery of a shaft portion and extends in the axial direction. Further, Patent Document 2 shows a structure in which a single flow path branches into a plurality of flow paths. Furthermore, Patent Document 3 shows that a lid is attached to the head of a fastening part to block a groove formed in the head, thereby forming an injection passage that communicates with a flow path branched into a plurality from a single flow path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, although Patent Document 2 has a flow path branched into one to five, it is insufficient to uniformly spray fluid (coolant) onto the cutting portion, and moreover, the head becomes thick to form the branched flow path. Further, the fastening component described in Patent Document 3 requires a lid which is a separate member for forming the injection passage, leading to complication of the structure and increase in the number of components.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a fastening component capable of satisfactorily spraying fluid onto a cutting portion while suppressing complication of the structure and the number of components.

Means for Solving the Problems

[0007] A fixing member according to an aspect of the present invention is a fastening component that is fastened to an arbor to fix a rotary cutting tool to the arbor, and includes a shaft portion screwed into a male screw of the arbor, an engagement hole formed at the axis center of the end face on the side opposite to the fastening side to the arbor, a first flow path formed at the axis center of the shaft portion and opening at the end face on the fastening side of the shaft portion to the arbor, a third flow path opening at a position away from the axis center at the end portion on the side opposite to the fastening side to the arbor, and a second flow path connecting the first flow path and the third flow path.

[0008] In the fastening component having the above structure, the fluid supplied to the first flow path is guided to the third flow path via the second flow path, and has a structure of being discharged from this third flow path to the cutting portion. Thereby, fluid can be satisfactorily sprayed onto the cutting portion, and moreover, complication of the structure and the number of components can be suppressed as compared with those provided with a separate member such as a lid or those subjected to complicated machining. Further, since the first flow path is formed at the axis center of the shaft portion, a decrease in strength due to forming the flow path can be suppressed.

[0009] The second flow path may be formed at the position closest to the engagement hole.

[0010] The first flow path may have a larger cross-sectional area than the second flow path, and the second flow path may have a larger cross-sectional area than the third flow path.

[0011] The third flow path may have a greater number of channels than the second flow path, and the second flow path may have a greater number of channels than the first flow path.

[0012] The total number of channels in the second flow path and the third flow path may be an even number.

[0013] The third flow path is at least divided into a third main flow path and a third sub-flow path. In a top view, the third main flow path may be arranged linearly with the second flow path, and the third sub-flow path may be arranged obliquely with respect to the second flow path.

[0014] Adjacent third sub-flow paths may be arranged such that their respective extension lines intersect each other.

[0015] At least a part of the second flow path may be in a curved shape.

[0016] The third flow path may be opened on the side surface at the end opposite to the fastening side to the arbor.

Advantages of the Invention

[0017] According to the present invention, there is provided a fastening component capable of spraying fluid well onto a cutting portion while suppressing the complexity of the structure and the number of components.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the fastening component 100 according to this embodiment is a bolt for fixing a cutter (rotary cutting tool) 20 to an arbor 10 and is fastened to the arbor 10. In this example, the case of fixing the cutter 20 to the arbor 10 is illustrated. However, the rotary cutting tool is not limited to a face mill, and may be a rotary cutting tool such as a shell end mill, a boring cutter, or a side cutter.

[0020] The arbor 10 is, for example, attached to a machine tool such as a machining center, and mainly has a shank portion 11, a flange portion 12, and a boss portion 13.

[0021] The shank portion 11 has a tapered shape and is inserted into a tapered hole (not shown) of the main shaft of the machine tool. Thereby, the arbor 10 is fixed to the main shaft of the machine tool.

[0022] The flange portion 12 is provided on the side opposite to the mounting side to the main shaft of the machine tool with respect to the shank portion 11. This flange portion 12 has a V-groove 12a and a key groove 12b. The V-groove 12a is a groove portion that is gripped when being stored in the magazine of the automatic tool changer of the machine tool or when exchanging tools by a tool changing arm, and is formed over the circumferential direction of the flange portion 12. The key groove 12b is a groove portion into which a key (not shown) of the machine tool is locked. By being locked to the key, the arbor 10 is fixed in the circumferential direction with respect to the main shaft of the machine tool.

[0023] The boss portion 13 is provided on the side opposite to the shank portion 11 with respect to the flange portion 12. The boss portion 13 has a mounting shaft 13a and a key 13b at its tip. The mounting shaft 13a is formed in a cylindrical shape having a female thread 13c on its inner peripheral surface. The key 13b is formed at two locations around the mounting shaft 13a.

[0024] The cutter 20 is a rotary cutting tool mainly used for face machining of a workpiece, and is mounted on the boss portion 13 of the arbor 10. The cutter 20 has a plurality (six in this example) of tip seats 21 and a mounting hole 22. The tip seats 21 project outward in the circumferential direction, and cutting tips 23 are respectively attached to these tip seats 21. The mounting hole 22 is formed at the center of the cutter 20, and the mounting shaft 13a provided on the boss portion 13 of the arbor 10 is inserted into this mounting hole 22. Further, the cutter 20 has two key holes (not shown) on the mounting side to the boss portion 13 of the arbor 10, into which the key 13b provided on the boss portion 13 is engaged.

[0025] The fastening component 100 is screwed and fastened to the female thread of the mounting shaft 13a of the boss portion 13 of the arbor 10 with the cutter 20 mounted on the boss portion 13 of the arbor 10. Thereby, the cutter 20 is fixed to the boss portion 13 of the arbor 10. Further, the fastening component 100 is a fixing bolt provided with a flow path for discharging the fluid (coolant) supplied through the arbor 10 to the cutting location by the cutting tip 23 of the cutter 20. Note that the fluid supplied to the cutting location is not limited to the coolant, and various lubricants and coolants can be used, and mist or air may also be supplied.

[0026] Next, the fastening component 100 will be described. As shown in FIG. 3, the fastening component 100 has a shaft portion 30 and an engagement hole 40. The shaft portion 30 has a head portion 31 at one end. The head portion 31 is formed in a disk shape having a larger diameter than the shaft portion 30.

[0027] The fastening component 100 is formed, for example, by a metal powder sintering 3D printer that three-dimensionally forms a shaped object using metal powder. Examples of the forming method by the metal powder sintering 3D printer include powder bed fusion, electron beam melting (EBM) that melts the powder using an electron beam, or selective laser melting (SLM) that melts the powder using a laser beam.

[0028] The shaft portion 30 is a portion that is screwed onto the mounting shaft 13a of the boss portion 13 of the arbor 10, and has an external thread formed on its outer periphery.

[0029] The engagement hole 40 is formed at the axial center on the end face of the fastening component 100 on the side opposite to the fastening side to the arbor 10. The engagement hole 40 is a hole into which a tool such as a hexagon wrench can be inserted, and a tool is inserted into this engagement hole 40 when fastening and releasing the fastening of the fastening component 100 to the arbor 10. Then, by rotating the tool, the fastening and release of the fastening component 100 are performed. Note that this engagement hole 40 is not limited to a hexagon hole, and can be a hole that can be changed to a shape into which various tools such as a Torx (registered trademark) hole can be inserted.

[0030] As shown in FIGS. 4 to 6, the fastening component 100 has a first flow path 50, a second flow path 60, and a third flow path 70.

[0031] The first flow path 50 is formed at the axial center AX of the shaft portion 30. This first flow path 50 opens at the end face on the fastening side to the arbor 10, and this opening portion is the inlet 51.

[0032] The second flow path 60 is formed in a greater number (eight in this example) than the first flow path 50. The second flow paths 60 are each formed at the position closest to the engagement hole 40. That is, these second flow paths 60 are formed at positions passing closer to the engagement hole 40 than the first flow path 50 and the third flow path 70. The second flow paths 60 are formed between the position near the end on the head 31 side in the shaft portion 30 and the position on the inner diameter side of the head 31, and the end on the shaft portion 30 side is communicated with the first flow path 50. These second flow paths 60 are each formed in a curved shape, and the middle portion thereof is passed near the engagement hole 40. These second flow paths 60 are formed radially around the axis center AX of the shaft portion 30.

[0033] The third flow path 70 is formed in a greater number (twenty-four in this example) than the second flow path 60. The third flow paths 70 are each formed in the head 31. One end of the third flow path 70 is communicated with the second flow path 60. In this example, three third flow paths 70 are respectively communicated with one second flow path 60. Further, the other end of the third flow path 70 is opened at the outer peripheral surface 31a of the head 31, which is the side surface at the end opposite to the fastening side to the arbor 10 of the fastening component 100. And the opening portion at the outer peripheral surface 31a of this head 31 is taken as the discharge port 71. In this example, the third flow path 70 is opened at the outer peripheral surface 31a of the head 31, but the third flow path 70 may be opened in a direction away from the axis center of the fastening component 100. For example, it may be opened at the end surface of the fastening component 100 (the upper surface of the head 31) or at the ridge line portion (the corner portion of the head 31) where the end surface and the side surface of the fastening component 100 intersect.

[0034] Thus, in the fastening component 100, the first flow path 50 and the third flow path 70 are connected by the second flow path 60. Thereby, as shown in FIG. 7, the fluid flowing in from the inlet 51 of the first flow path 50 through the arbor 10 (see arrow A in FIG. 7) flows through the first flow path 50 and is branched into the second flow paths 60, and further flows through the second flow paths 60 and is branched into the third flow paths 70. Then, the fluid flows through each third flow path 70 and is discharged radially outward from the head 31 from the discharge port 71, and is discharged toward the cutting portion by the cutting tip 23 of the cutter 20 (see arrow B in FIG. 7).

[0035] Here, the first flow path 50 has a larger cross-sectional area than the second flow path 60, and the second flow path 60 has a larger cross-sectional area than the third flow path 70. That is, the cross-sectional areas of the first flow path 50, the second flow path 60, and the third flow path 70 decrease in this order. Therefore, when the fluid flows from the first flow path 50 to the second flow path 60 and the third flow path 70 in sequence, the pressure loss of the fluid can be suppressed, and it can be sprayed well onto the cutting portion.

[0036] Also, the total number of the second flow paths 60 and the third flow paths 70 is an even number. In this example, there are 8 second flow paths 60 and 24 third flow paths 70, and the total number of these is 32. And in the fastening component 100, these second flow paths 60 and third flow paths 70 are arranged at point-symmetrical positions, whereby the weight balance and dynamic balance of the fastening component 100 are well maintained.

[0037] Also, as shown in FIG. 8, the three third flow paths 70 communicated with each second flow path 60 are one third main flow path 73 and two third sub-flow paths 75. And in a top view of the fastening component 100, the third main flow path 73 is arranged linearly with the second flow path 60, and the third sub-flow path 75 is arranged obliquely with respect to the second flow path 60. Thereby, the third sub-flow path 75 extends in a direction gradually separating from the third main flow path 73 from the communication portion with the second flow path 60 toward the outer peripheral surface 13a of the head 31.

[0038] Thereby, the fluid guided from the second flow path 60 to the third main flow path 73 is discharged on the extension line of the second flow path 60, and the fluid guided from the second flow path 60 to the third sub-flow path 75 is discharged in an oblique direction with respect to the second flow path 60. Thereby, the fluid can be sprayed evenly onto the cutting portion.

[0039] Also, in the head 31, the adjacent third sub-flow paths 75 are arranged such that their respective extension lines L intersect each other. Therefore, the flow rates are compensated by the collision of the fluids discharged from the adjacent third sub-flow paths 75, and sufficient fluid can be sprayed onto the cutting portion.

[0040] As described above, according to the fastening component 100 according to the present embodiment, the fluid supplied to the first flow path 50 is guided to the third flow path 70 via the second flow path 60 and discharged from the third flow path 70 to the cutting portion. Thus, the fluid can be satisfactorily sprayed onto the cutting portion, and moreover, the complexity of the structure and the number of components can be suppressed as compared with those provided with a separate member such as a lid or those subjected to complicated machining. Further, since the first flow path 50 is formed at the axial center AX of the shaft portion 30, a decrease in strength due to forming the flow path can be suppressed.

[0041] Further, by forming the second flow path 60 at the position closest to the engagement hole 40, the first flow path 50 and the third flow path 70 can be connected while avoiding the engagement hole 40 and achieving miniaturization.

[0042] Moreover, since the second flow path 60 has a curved shape, it is possible to suppress the flow velocity loss of the fluid flowing through the second flow path 60 and to bring the second flow path 60 closer to the engagement hole 40 to achieve the compactification of the fastening component 100.

[0043] Further, since the number of the third flow paths 70 is larger than that of the second flow paths 60 and the number of the second flow paths 60 is larger than that of the first flow paths 50, the fluid discharged from the third flow path 70 can be evenly sprayed onto the cutting portion. Further, by forming the third flow paths 70 having a larger number than the second flow paths 60, the number of the second flow paths 60 can be suppressed, and the fluid can be satisfactorily sprayed onto the cutting portion while suppressing a decrease in strength around the engagement hole 40.

Explanation of reference numerals

[0044] 10 Arbor 13c Female screw 20 Cutter (rotary cutting tool) 30 Shaft portion 40 Engagement hole 50 First flow path 60 Second flow path 70 Third flow path 73 Third main flow path 75 Third sub-flow path 100 Fastening part AX-axis center

Claims

1. A fastening component that is fastened to a spindle and fixes a rotary cutting tool to the spindle, a shaft portion screwed into the internal thread of the spindle, an engagement hole formed at the axis center on the end face opposite to the fastening side to the spindle, a first flow path formed at the axis center of the shaft portion and opening at the end face on the fastening side of the shaft portion to the spindle, a third flow path opening at a position away from the axis center at the end opposite to the fastening side to the spindle, a second flow path connecting the first flow path and the third flow path, having a fastening component.

2. The second flow path is formed at the position closest to the engagement hole, The fastening component according to claim 1.

3. The first flow path has a larger cross-sectional area than the second flow path, and the second flow path has a larger cross-sectional area than the third flow path, The fastening component according to claim 1.

4. The number of the third flow paths is larger than that of the second flow paths, and the number of the second flow paths is larger than that of the first flow paths, The fastening component according to claim 1.

5. The total number of the second flow path and the third flow path is an even number, The fastening component according to claim 1.

6. The third flow path is at least divided into a third main flow path and a third sub-flow path, In a top view, the third main flow path is arranged linearly with the second flow path, and the third sub-flow path is arranged obliquely with respect to the second flow path, The fastening component according to claim 1.

7. The adjacent third sub-flow paths are arranged such that their extension lines intersect each other, The fastening component according to claim 6.

8. At least a part of the second flow path has a curved shape, The fastening component according to claim 1.

9. The third flow path is opened on a side surface at an end opposite to the fastening side to the arbor, The fastening component according to claim 1.

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