Milling cutter

Abstract

The problem to be solved by the present invention is to provide a milling cutter having a tip that can be replaced with ease at low cost.　The milling cutter has: a blade part 10 that has a plurality of tips 12 each provided with a bottom blade 121 and an outer peripheral blade 122, and a blade body part 11 which is a plate-like body to which the plurality of tips 12 are fixed at an outer periphery and has grooves 113 formed to match the positions of the tips 12; and a body 20 having a front end part 21, which has a front end surface to which the rear end surface of the blade body part 11 is fixed in a contactable and detachable manner, and a front end outer peripheral section which has an outer diameter of 100 / 100-92 / 100 with respect to the outer diameter of the blade part 10 and in which body-side grooves 211 continuous to the grooves 113 of the blade body part 11 in close contact are formed, the body 20 being rotatable about a rotation axis. A blade part mounting hole 11a is formed in the center of the blade body part 11, and a body mounting hole / orifice is formed in the center of the front end part 21. By inserting a fastening bolt in which the outer peripheral surface of the shaft part is in close contact with the inner peripheral surface of each mounting hole into the hole, radial positioning becomes possible.

Description

Milling cutter

[0001] The present invention relates to a milling cutter.

[0002] Milling cutters have tips made of cemented carbide, polycrystalline diamond, cubic boron nitride (CBN), or other ceramics attached to the outer periphery of a disk or cylinder. Among these, there is a type of milling cutter in which a replaceable blade with a tip fixed to the outer periphery of a disk is detachably attached to the tip of the body.

[0003] A typical insert-type milling cutter has multiple replacement blades, each attached to the body, making blade replacement cumbersome and limiting the number of blades that can be installed, especially when the blade diameter is small. In addition, a conventional head-replaceable milling cutter (Patent Document 2) has a replaceable blade with multiple cutting blades, and a spigot shaft and threaded portion are provided on the replaceable blade, and a spigot hole is provided on the body to fasten and align the replaceable blade to the body. However, due to the complex structure, it is difficult to manufacture the replaceable blade inexpensively. In addition, other conventional milling cutters (Patent Documents 1 and 3) have a replaceable blade with a spigot hole and a spigot shaft on the body to fasten and align the replaceable blade to the body, but interference from the fastening structure makes it difficult to reduce the size.

[0004] WO2021 / 060271A1 JP 2011-056594 A JP 2001-162430 A

[0005] The present invention was completed in view of the above-mentioned circumstances, and an object of the present invention is to provide a milling cutter in which the cutting portion can be replaced more easily than before and in which replaceable cutting edges can be manufactured at low cost and which can be made smaller.

[0006] (1) The milling cutter of the present invention that solves the above-mentioned problems has a cutting section having a plurality of inserts and a cutting body that is a plate-like body with cutting section mounting holes that penetrate the cutting body in the thickness direction and to which the plurality of inserts are fixed on the outer periphery; a front end surface to which the rear end surface of the cutting body can be attached in a manner that allows it to be detached; a front end portion in which a body mounting hole / hole opens in the center of the front end surface; an outer diameter of 100 / 100 to 92 / 100 based on the outer diameter of the cutting section (100 / 100); and a fastening bolt in which at least a portion of the outer peripheral surface of the shank between the head and the threaded portion is inserted into the inner peripheral surfaces of the cutting section mounting hole and the body mounting hole / hole, and when fastened, the outer peripheral surface of the shank is in close contact with the inner peripheral surfaces of the cutting section mounting hole and the body mounting hole / hole. In this specification, "hole" means a through-hole and "hole" means a bottomed recess, but they are not strictly distinguished, and the term "hole / bore" encompasses both a through-hole and a bottomed recess. The milling cutter of the present invention can be arbitrarily combined with one or more of the following components (2) to (5).

[0007] (2) In particular, it is preferable that a groove be formed on the outer periphery of the blade body in accordance with the position of the tip, and that a body side groove be formed on the outer periphery of the tip that connects to the groove when the blade body is in close contact. (3) The rear end surface of the blade body and the front end surface of the tip have a rotation prevention mechanism between the blade and the body. (4) The body is formed with a cutting fluid supply passage that communicates between a cutting fluid supply port opening at the rear end and a cutting fluid injection port opening at the front end.

[0008] (5) The blade portion mounting hole and the body mounting hole / hole are cylindrical and have the same or different diameters, and the outer surface of the shank of the fastening bolt is inserted via a clearance so as to be in line with the entire inner surface of the blade portion mounting hole and the entire inner surface of the body mounting hole / hole, with the blade body portion fastened to the tip portion.

[0009] The milling cutter of the present invention can accurately attach the blade body with a relatively small number of fastening bolts. Furthermore, since the number of fastening bolts required to attach the blade body is small, the size of the fastening bolts can be relatively large, resulting in high fastening strength.

[0010] 2 is a perspective view of a milling cutter of embodiment 1. FIG. 3 is a plan view of a milling cutter of embodiment 1. FIG. 4 is a front view of a milling cutter of embodiment 1. FIG. 5 is an exploded view of a milling cutter of embodiment 1. FIG. 6 is a cross-sectional view taken along the line A-A in FIG. 2. FIG. 7 is a perspective view of a milling cutter of embodiment 2. FIG. 8 is an exploded view of a milling cutter of embodiment 2. FIG. 9 is a cross-sectional view of embodiment 2.

[0011] The milling cutter of the present invention will be described in detail below based on an embodiment with reference to the drawings. The milling cutter of this embodiment is a multi-blade milling cutter with an increased number of blades, and is particularly suitable as a face milling cutter. It is particularly suitable for use in light metal processing. In this specification, the direction toward the workpiece in the direction of the milling cutter's rotation axis is referred to as the leading direction, and the opposite direction is referred to as the trailing direction. Due to issues with creating drawings from 3D models, lines that do not clearly appear on the surface of the actual product may appear in areas where the curvature of the curved surface changes (e.g., groove 113 and body groove 211 in Figures 1, 3, and 4, and areas corresponding to the groove and body groove in Figures 6 and 7).

[0012] Note that the numerical range "x to y" described in this specification includes a lower limit x and an upper limit y. Furthermore, a new numerical range can be constructed by arbitrarily combining these upper and lower limits, as well as the numerical values ​​listed in the specification or examples. The new numerical range can also be a range that does not include one or both of the upper and lower limits. For example, a range exceeding x or a range less than y can be adopted. Furthermore, numerical values ​​arbitrarily selected from any of the above numerical ranges can be used as the upper and lower limits of the new numerical range.

[0013] The milling cutter of this embodiment has a cutting edge, a body, and a fastening bolt. The cutting edge and the body are fixed so that the rear end surface of the cutting edge body that constitutes the cutting edge is in close contact with and abuts against the front end surface of the body. The two are fixed together by a fastening bolt. The rotation axis of the fastening bolt is arranged to coincide with the rotation axis of the cutting edge and the body.

[0014] The cutting section has multiple tips and a blade body to which the tips are fixed. The tips are sharpened with a bottom cutting edge and a peripheral cutting edge. The material that makes up the tips is not particularly limited, but examples include cemented carbide, polycrystalline diamond, CBN, and other ceramics. In particular, the material of the cutting edge and other parts can be changed. The number of tips is not particularly limited.

[0015] If the tip becomes worn or damaged, you can continue using the tool by removing the cutting section from the body and replacing it with a usable cutting section. Replacing the cutting section is easier than replacing or adjusting the tip. The removed cutting section can be re-sharpened, repaired, or replaced to restore the tip.

[0016] The blade body is generally plate-shaped and has a shape similar to a disk overall. The material for forming the blade body is not particularly limited, but alloy tool steel is preferred. The thickness of the blade body is preferably 4 mm or more, more preferably 5 mm or more, and even more preferably 6 mm or more. A thicker thickness can suppress deformation of the blade body, thereby improving the machining accuracy using the milling cutter of this embodiment.

[0017] It is desirable that the rear end surface of the blade main body, which is the surface that abuts against the body, can be in close contact with the front end surface of the body described below, and it is preferable that the rear end surface and the front end surface have complementary shapes to improve the close contact. It is particularly desirable that the rear end surface and the front end surface are flat. The area where the rear end surface of the blade main body and the front end surface of the body are in close contact is preferably near the area where the tip is fixed. Since the close contact of the front end surface of the body can suppress deflection of the blade main body, by making the contact near the area where the tip is fixed, it is possible to suppress deflection of the area where the tip is fixed, thereby improving processing accuracy.

[0018] The blade body is provided with a blade attachment hole that penetrates in the thickness direction. The blade attachment hole works in conjunction with a body attachment hole / hole (to be described later) to precisely fix the blade to the body. Details will be explained together with the body attachment hole / hole (to be described later).

[0019] Multiple tips are fixed to the outer periphery of the blade body. Tips can be fixed by brazing, welding, adhesive bonding, or other methods. Tips can be fixed straight or with either a positive or negative helix angle depending on the application of the workpiece, etc. Increasing the helix angle in the positive direction improves chip removal and cutting performance, while increasing it in the negative direction improves the durability of the cutting edge formed on the tip. The helix angle can be approximately -20° to 20°, -15° to 15°, or -10° to 10° relative to the rotation axis, and these upper and lower limit values ​​can be combined as desired. The tip can be provided with either an end cutting edge or a peripheral cutting edge. The end cutting edge and peripheral cutting edge of the tip can be formed with any rake angle.

[0020] The arrangement of the multiple tips fixed to the outer periphery of the blade body is not particularly limited. For example, they can be arranged in rotationally symmetrical positions around the rotation axis, or in uneven positions that are not rotationally symmetrical. It is preferable that grooves are formed in the blade body to match the positions where the tips are fixed.

[0021] When fixing the tip to the outer periphery of the blade body, it is preferable to fix it so that the sum S of the runout of the rear end face of the blade body and the runout of the bottom cutting edge is 15 μm or less, since this allows for highly accurate milling. In this specification, "runout" refers to the maximum value of the runout width of the cutting edge when the blade part is rotated once around the rotation axis. The sum S is preferably 10 μm or less, and more preferably 5 μm or less.

[0022] The body has a tip to which the blade is fixed. The material for forming the body is not particularly limited, but alloy tool steel is preferred. The body can be formed in two or more sections, each section being made of a different material. The tip has a tip surface to which at least a portion of the rear end surface of the blade main body is attached in a tight and detachable manner.

[0023] The tip portion has a body mounting hole / hole opening in the center of the tip surface. A fastening bolt is inserted through the blade mounting hole with the rear end surface of the blade body of the blade portion tightly contacted to the tip surface of the tip portion. The inserted fastening bolt fastens and fixes the blade body to the tip portion. The fastening bolt has a shank with no thread formed between the threaded portion and the head. The head is biased toward the rear end of the blade body in the axial direction, thereby pressing and fastening the blade body toward the tip surface of the tip portion of the body so that the rear end surface is tightly contacted. Since it is desirable that the head does not protrude distally beyond the tip bottom cutting edge of the blade portion, the shape of the distal end side of the blade body is preferably such that the head is embedded. Considering damage to the tip, it is preferable that it does not protrude distally from the blade body.

[0024] When a flat head bolt with a flat head is used as the fastening bolt, the portion of the blade attachment hole in the blade body that is not in close contact with the shank toward the tip can be tapered, increasing in diameter as it moves toward the tip. The inclination of the taper is preferably the same as that of the flat head bolt. A larger head diameter is particularly preferable, as it increases the area that presses against the blade body, improving the adhesion between the blade body and the tip. Here, the portion where the head presses against the blade body (pressing portion) is preferably approximately circular, and the outer diameter of the pressing portion can have a preferred lower limit of 40%, 50%, or 60% of the outer diameter of the blade, and a preferred upper limit of 70%, 80%, or 90%. These lower and upper limits can be combined as desired.

[0025] The fastening bolt can be, and preferably is, configured such that the head and shank are integrated, but it may also be configured such that the head is removable. To make the head removable, a thread can be formed on the side connected to the head, opposite the side connected to the threaded portion of the shank, and a nut or cap screw-like member formed to screw onto the thread can be used as the head.

[0026] The shank is formed in a position that allows it to come into close contact with both the blade portion mounting hole and the body mounting hole / hole when the fastening bolt is fastened to the blade portion mounting hole and the body mounting hole / hole (fastened state). The outer peripheral surface of the shank is shaped to come into close contact with the inner peripheral surfaces of the blade portion mounting hole and the body mounting hole / hole in the fastened state. The shank is formed in a position that allows it to come into close contact with both the blade portion mounting hole and the body mounting hole / hole when the fastening bolt is fastened to the blade portion mounting hole and the body mounting hole / hole (fastened state). By adopting this configuration, the blade is positioned in a direction perpendicular to the rotation axis with the body via the inner peripheral surface of the blade portion mounting hole, the outer peripheral surface of the shank of the fastening bolt relative to that inner peripheral surface, and the inner peripheral surface of the body mounting hole / hole relative to that outer peripheral surface.

[0027] For example, the outer peripheral surface of the shank, the inner peripheral surfaces of the blade attachment hole, and the body attachment hole / hole can be cylindrical or partially or entirely formed as a truncated cone. A cylindrical shape is particularly preferable, as this improves machining accuracy. By reducing the clearance between the outer peripheral surface of the shank and the blade attachment hole / hole in the fastened state, the attachment accuracy in the direction perpendicular to the rotation axis of the blade and body is determined. The size of the clearance can be, for example, approximately 10 μm to 20 nm.

[0028] The diameters of the outer circumferential surface of the shank in the fastened state at the portion where it comes into close contact with the inner circumferential surface of the blade section mounting hole and the portion where it comes into close contact with the body mounting hole / bore may be the same or different. Furthermore, even at the portion where the outer circumferential surface of the shank in the fastened state comes into close contact with the inner circumferential surface of the blade section mounting hole, there may be portions with different diameters at different axial locations. Similarly, there may be portions with different diameters at the portion where the outer circumferential surface of the shank in the fastened state comes into close contact with the inner circumferential surface of the body mounting hole / bore.

[0029] In addition, if the diameters of the portions of the outer peripheral surface of the shank that come into close contact with the blade section mounting hole and the body mounting hole / hole are different, it is preferable to change the diameters so that they are the same or gradually smaller as the direction of insertion of the fastening bolt into the blade section mounting hole and the body mounting hole / hole, or to combine these. Furthermore, the inner peripheral surfaces of the blade section mounting hole and the body mounting hole / hole may contact the outer peripheral surface of the shank over the entire surface, a partial surface, or just a point. Furthermore, they do not necessarily have to contact just a point. The shank of the fastening bolt, the blade section mounting hole, and the body mounting hole / hole have a fit tolerance that limits movement of the fastening bolt in a direction perpendicular to the axial direction, ensuring the installation accuracy between the blade section and the body.

[0030] The tip surface is preferably configured to fit closely to the blade body, particularly near the outer periphery of the blade body. Furthermore, the tip surface is preferably configured to fit closely to the entire rear end surface of the blade. This tip surface has a shape complementary to the rear end surface of the blade body. If the rear end surface is flat, the tip surface is also flat. If the rear end surface is uneven, the tip surface has unevenness that fits closely to the unevenness. This uneven shape can also function as a rotation prevention mechanism by preventing relative rotation between the rear end surface and the tip surface. Specifically, an example of a rotation prevention mechanism formed as a complementary shape between the tip surface and the rear end surface is a protruding member such as a pin on one of the tip surface or the rear end surface and a rotation prevention hole on the other of the tip surface or the rear end surface large enough to accommodate the protruding member. Inserting the protruding member into the rotation prevention hole limits relative rotation between the blade and the body. Another possible rotation prevention mechanism is a removable key.

[0031] The shape of the outer periphery of the tip portion (tip outer periphery) is preferably such that the projection shape in the direction of the rotation axis is equivalent to the projection shape of the blade body portion in the direction of the rotation axis. Specifically, the outer diameter is 100 / 100 to 92 / 100, with the outer diameter of the blade portion as the reference (100 / 100). In particular, the shape of the tip surface is also preferably 100 / 100 to 92 / 100, with the outer diameter of the blade portion as the reference. The lower limit values ​​of the outer diameters of the tip portion and tip surface are preferably 96 / 100. By making the body (tip portion) have an outer shape similar to the outer shape of the blade body portion, it is possible to suppress wobbling due to rotation of the blade body portion. The outer diameter of the blade body portion is not particularly limited, but can be approximately 25 mm to 50 mm.

[0032] The outer periphery of the tip preferably has a body groove formed thereon, which is continuous with the groove in the blade body that is in close contact with it. Chips generated during machining are discharged through the groove in the blade body and then through the body groove, if present. The projected shape of the body groove in the direction of the rotation axis is generally the same as the projected shape of the groove in the blade body.

[0033] The body can be formed with a cutting fluid supply passage having an outlet for supplying cutting fluid to the body groove. The opening diameter of the outlet is not particularly limited, but can be approximately 0.5 mm to 3 mm. The outlet is formed as close to the cutting edge as possible in the body groove. In particular, it is formed so as to open at a portion adjacent to the tip surface. The cutting fluid supply passage is formed as nearly parallel as possible to the rotation axis so that the cutting fluid is discharged from the outlet toward the tip of the rotation axis so that the cutting fluid is discharged from the outlet toward the tip of the rotation axis. If the length of the milling cutter in the rotation axis direction is insufficient, the cutting fluid supply passage may be formed in a bent shape. If there are multiple body grooves connected to the groove corresponding to the portion where the tip is fixed, it is preferable that the outlet open to all of the body grooves.

[0034] When the tip fixed to the blade body has a positive helix angle (axial rake), a second peripheral cutting edge can be provided on the outer periphery rearward of the tip. The second peripheral cutting edge has a negative helix angle. When cutting with a peripheral cutting edge having a positive helix angle, chips are forced toward the rear end, which can result in so-called burrs. These burrs can be removed by forcing them toward the tip with a second peripheral cutting edge having a negative helix angle. The second peripheral cutting edge is attached to the second tip. The second tip may be fixed to the rear end side of the blade body, or to the tip side of the body. Furthermore, the second cutting edge may be configured by being fixed to a second blade body, which is a separate member from the blade body and the body.

[0035] The second blade body portion preferably has the same projected shape in the direction of the rotation axis as the blade body portion, and preferably has approximately the same thickness. In many cases, it is sufficient to have fewer second tips than the tips on the blade portion.

[0036] 1 to 5, the milling cutter 1 of this embodiment has a cutting portion 10 and a body 20. The cutting portion 10 has a cutting body portion 11 and twelve tips 12. The cutting portion 10 is fastened to the body 20 with a fastening bolt 30. The fastening bolt 30 has a hexagonal hole 31 in its head 34. The cutting portion 10 can be easily detached and attached using the fastening bolt 30, and no further adjustment is required. Therefore, even if the tips 12 are worn or chipped, machining can be resumed immediately by replacing the entire cutting portion 10. Because only the cutting portion 10 needs to be replaced, costs can be reduced compared to preparing a spare milling cutter and replacing the entire milling cutter.

[0037] The milling cutter 1 of this embodiment has a rotation axis extending in the front-to-back direction of the paper at the center of Fig. 2. The front direction of the paper in Fig. 2 and the upward direction in Fig. 3 are the leading end direction, and the rear direction of the paper in Fig. 2 and the downward direction in Fig. 3 are the trailing end direction.

[0038] The blade body 11 is made of alloy tool steel and has a generally disk-like shape with a thickness of 5 mm and a diameter of 50 mm. The blade body 11 has a blade attachment hole 11a in the center and two anti-rotation holes 11b around the blade attachment hole 11a into which the tip of an anti-rotation pin 214 serving as an anti-rotation mechanism can be inserted.

[0039] The blade mounting hole 11a has an inner diameter such that its inner peripheral surface is in close contact with the outer peripheral surface of the shank 38 of the fastening bolt 30. The fastening bolt 30 has a flat head 34, a threaded portion 36, and a shank 38 that connects the head 34 and the threaded portion 36. A recess that can accommodate the flat head 34 is formed on the distal end of the blade body 11. The head 34 is slightly recessed so as not to protrude distally from the distal end of the tip 21. The outer diameter of the head 34 is 32 mm, which is 64% of the outer diameter (50 mm) of the blade body 11 of the cutting portion 10. The fastening bolt 30 has a cutting fluid supply passage 32 that connects an inlet 32b that opens toward the rear end of the threaded portion 36 to an outlet 32a that opens toward the rear end of the shank 38 at a position slightly reduced in diameter.

[0040] Twelve tips 12 are fixed to the outer periphery of the blade body 11. The outer periphery of the blade body 11 is divided into 12 sections at 30° intervals, and tip seats 112 are provided in the 12 sections. Twelve tips 12 are fixed to each of the 12 tip seats 112. Grooves 113 are formed in the blade body 11 at positions corresponding to the positions of the 12 divided tip seats 112.

[0041] The tip 12 is sharpened to a bottom cutting edge 121 and a peripheral cutting edge 122. The corners of the bottom cutting edge 121 and the peripheral cutting edge 122 are sharpened with chamfering edges. The tip 12 is fixed to the tip seat 112 so that the bottom cutting edge 121 protrudes toward the tip of the blade body 11 and the peripheral cutting edge 122 protrudes in the outer diameter direction of the blade body 11. Fixation to the tip seat 112 can be performed by brazing. The tip 12 is fixed so that the peripheral cutting edge 122 has a positive helix angle. The bottom cutting edge 121 has a positive rake angle.

[0042] The outer shapes of the leading edge surface and the trailing edge surface of the blade body 11 are the same projected shape in the direction of the rotation axis and are parallel planes perpendicular to the rotation axis. The trailing edge surface of the blade body 11 can be fully in contact with the leading edge surface of the leading edge portion 21 of the body 20, thereby suppressing deformation of the blade body 11. Therefore, since the precision of the trailing edge surface of the blade body 11 and the leading edge surface of the leading edge portion 21 directly affects the machining precision of the milling cutter, the blade body 11 is manufactured to minimize runout of the leading edge surface and the trailing edge surface. Specifically, the sum S of the runout of the bottom cutting edge 121 attached to the tip 12 and the runout of the trailing edge surface is set to 5 μm or less. Furthermore, the thickness of the blade body 11 makes it less likely for bending to occur due to external forces or thermal fluctuations, allowing for high machining precision.

[0043] The body 20 has a tip portion 21 and a base portion 22 integrally formed on the rear end side of the tip portion 21. The body 20 is made of alloy tool steel or aluminum alloy. A body mounting hole 21a is formed on the tip surface, into which a fastening bolt 30 is fastened. The body mounting hole 21a has an inner diameter such that the inner peripheral surface of the portion where the shank 38 of the fastening bolt 30 is located is in close contact with the shank 38. The threaded portion 36 of the fastening bolt 30 is threadedly engaged with the arbor of a processing device. The base portion 22 has a substantially cylindrical outer shape, and a fitting groove 222 is cut out at the rear end side so that the threaded portion 36 of the fastening bolt 30 can be connected to the processing device. It is also possible to form a threaded portion in the body mounting hole 21a that can be fastened with the threaded portion 36 of the fastening bolt 30, and fasten the threaded portion 36.

[0044] The external shape of the tip portion 21 when projected in the direction of the rotation axis is generally the same as the external shape of the blade body portion 11. The tip surface of the tip portion 21 is flat and is in close contact with the rear end surface of the blade body portion 11. Therefore, the rear end surface of the blade body portion 11 is supported as a whole by the tip surface of the tip portion 21, which can prevent the blade body portion 11 from bending during cutting. From the perspective of preventing bending during cutting, it is preferable that the tip surface have a shape projected in the direction of the rotation axis such that the tip surface is located near the tip seat 112 to which the tip 12 is fixed.

[0045] The outer periphery of the tip portion 21 is formed with a body groove 211 extending from the groove 113 formed in the blade body 11 with the same cross-sectional shape as the groove 113. The body groove 211 is slightly twisted so as to advance clockwise toward the tip. Each body groove 211 has a cutting fluid outlet 213a. A cutting fluid supply port 213b opens inside the body 20, and supply paths 213 are formed connecting each cutting fluid supply port 213b and the cutting fluid outlet 213a. Cutting fluid flows from the inlet 32b of the fastening bolt 30 through the outlet 32a, then through a gap between the thread portion 36 and the body to the cutting fluid supply port 213b and is discharged from the cutting fluid outlet 213a toward the tip 12.

[0046] (Embodiment 2) A milling cutter of this embodiment will be described with reference to the drawings. The milling cutter of this embodiment is composed of substantially the same elements as the milling cutter of embodiment 1, and the same components are designated by the same reference numerals with an "A" prefix.

[0047] As shown in FIG. 6, the milling cutter A1 of this embodiment has a cutting edge A10, a body A20, and a fastening bolt A30.

[0048] The milling cutter of this embodiment has a smaller outer diameter than the milling cutter of embodiment 1. The body A20 of this milling cutter has a tip end A21, a base end A22, and a shank A23 at the rear end side of the base end A22. This milling cutter is attached to a machine tool via the shank A23.

[0049] 1, A1... milling cutter 10, A10... cutting portion 11... cutting body portion 11a... cutting portion mounting hole 12... tip 112... tip seat 113... groove 121... bottom cutting edge 122... peripheral cutting edge 20, A20... body 21, A21... tip portion 21a... body mounting hole 22, A22... base end portion A23... shank 211... body side groove 213... supply path 213a... cutting fluid outlet 213b... cutting fluid supply port 214... pin 222... fitting groove 30, A30... fastening bolt 32... cutting fluid supply path 32a... outlet 32b... inlet 34... head 36... threaded portion 38... shaft portion

Claims

1. A milling cutter having: a cutting section having a plurality of inserts and a blade body which is a plate-like body with cutting section mounting holes that penetrate the thickness direction and to which the plurality of inserts are fixed on the outer periphery; a body which has a front end surface to which the rear end surface of the blade body can be attached in a manner that allows it to be detached, has a front end where a body mounting hole / hole opens at the center of the front end surface, and has an outer diameter of 100 / 100 to 92 / 100 based on the outer diameter of the cutting section (100 / 100); and a fastening bolt in which at least a portion of the outer surface of the shank between the head and threaded portion is inserted into the inner surfaces of the cutting section mounting hole and the body mounting hole / hole, and when fastened, the outer surface of the shank is in close contact with the inner surfaces of the cutting section mounting hole and the body mounting hole / hole.

2. A milling cutter as claimed in claim 1, wherein a groove is formed on the outer periphery of the blade body in accordance with the position of the tip, and a body side groove is formed on the outer periphery of the tip that connects to the groove when the blade body is in close contact.

3. A milling cutter as claimed in claim 1, wherein the rear end surface of the cutting body and the tip surface of the tip portion have a rotation prevention mechanism between the cutting portion and the body.

4. A milling cutter as described in claim 1, wherein the body has a cutting fluid supply passage formed therein that connects the cutting fluid supply port opening at the rear end and the cutting fluid injection port opening at the front end.

5. A milling cutter as described in claim 1, wherein the cutting edge mounting hole and the body mounting hole / hole are cylindrical and have the same or different diameters, and the outer surface of the shank of the fastening bolt is inserted via a clearance so as to achieve the required assembly accuracy with the entire inner surface of the cutting edge mounting hole and the entire inner surface of the body mounting hole / hole when the cutting edge body is fastened to the tip portion.

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