milling machine

Abstract

The challenge to be addressed is to provide a milling cutter that allows for inexpensive and easy replacement of the inserts. The device has a blade section 10 having a plurality of chips 12 with a bottom blade 121 and an outer peripheral blade 122, and a blade body 11 which is a plate-like body on which the plurality of chips 12 are fixed to the outer circumference, with grooves 113 formed to match the positions of the chips 12; a tip section 21 having a tip surface to which the rear end surface of the blade body 11 can be fixed in close contact and detachably, and a tip outer circumference having an outer diameter of 100 / 100 to 92 / 100 based on the outer diameter of the blade section 10, and a body side groove 211 which is connected to the groove 113 of the blade body 11 that is in close contact with it, and a body 20 which is rotatable around a rotation axis. A blade section mounting hole 11a is formed in the center of the blade body 11, and a body mounting hole / hole is formed in the center of the tip section 21, and radial positioning is possible by inserting fastening bolts into which the outer circumference surface of the shaft is in close contact with the inner circumference surface of the respective mounting hole.

Description

Technical Field

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

Background Art

[0002] In a milling cutter, a tip made of cemented carbide, polycrystalline diamond, cubic boron nitride (CBN), or other ceramics is attached to the outer periphery of a disk or a cylinder. Among them, there is a milling cutter in which an exchangeable blade with a tip fixed to the outer periphery of a disk is detachably fixed to the tip of a body.

[0003] In a general insert type milling cutter, since it has a plurality of exchangeable blades and the exchangeable blades are respectively attached to the body, the replacement of the blade part is complicated, and particularly when the diameter of the blade part is small, the number of exchangeable blades that can be mounted is limited. In addition, in a conventional head-exchangeable milling cutter (Patent Document 2), an inlay shaft and a screw part are provided on an exchangeable blade having a plurality of cutting edges, and an inlay hole is provided in the body. The exchangeable blade and the body are fastened and aligned, but since it has a complicated structure, it has been difficult to manufacture the exchangeable blade at a low cost. In addition, in other conventional milling cutters (Patent Documents 1 and 3), an inlay hole is provided in the exchangeable blade and an inlay shaft is provided in the body, and the exchangeable blade and the body are fastened and aligned. However, miniaturization has been difficult due to interference in the fastening structure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] This invention was completed in view of the above circumstances, and aims to solve the problem of providing a milling cutter that can manufacture replacement blades that are easier to replace and smaller than conventional blades at a low cost. [Means for solving the problem]

[0006] (1) The milling cutter of the present invention, which solves the above problems, has a blade portion having a plurality of chips and a blade body portion which is a plate-like body having a blade portion mounting hole that penetrates in the thickness direction and is fixed to the outer circumference of the plurality of chips, a tip portion having a tip surface to which the rear end surface of the blade body portion can be fixed in close contact and detachably, a body mounting hole / hole opening in the center of the tip surface, an outer diameter of 100 / 100 to 92 / 100 with the outer diameter of the blade portion as the reference (100 / 100), and a fastening bolt in which at least a part of the outer surface of the shaft portion between the head and the threaded portion is inserted into the inner surface of the blade portion mounting hole and the body mounting hole / hole, and when fastened, the outer surface of the shaft portion is shaped to be in close contact with the inner surface of the blade portion mounting hole and the body mounting hole / hole. In this specification, "hole" refers to a recess that goes all the way through, and "hole" refers to a recess with a bottom. However, these terms are not strictly distinguished, and the term "hole / hole" encompasses both forms of recesses that go all the way through and recesses that do not go all the way through and have a bottom. The milling cutter of the present invention can be made by arbitrarily combining one or more of the following components (2) to (5).

[0007] (2) In particular, grooves are formed on the outer circumference of the blade body portion in accordance with the position of the tip, Preferably, a body side groove is formed on the outer circumference of the tip portion, which connects to the groove when the blade body portion is in close contact with it. (3) The rear end surface of the blade body and the front end surface of the front end are provided with a rotation prevention mechanism between the blade and the body. (4) The body has a cutting fluid supply passage that connects a cutting fluid supply port opening at the rear end and a cutting fluid spray port opening at the front end.

[0008] (5) The blade mounting hole and the body mounting hole / hole are cylindrical in shape and have the same or different diameters. The outer circumferential surface of the shaft portion of the fastening bolt is inserted with a clearance between it and the entire inner surface of the blade mounting hole and the inner surface of the body mounting hole / hole, respectively, while the blade body is fastened to the tip portion, so as to achieve the required machining accuracy. [Effects of the Invention]

[0009] The milling cutter of the present invention allows for precise mounting of the blade body with a relatively small number of fastening bolts. Furthermore, because fewer fastening bolts are required to mount the blade body, it becomes possible to use relatively larger fastening bolts, resulting in high fastening strength. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the milling machine of Embodiment 1. [Figure 2] This is a plan view of the milling machine of Embodiment 1. [Figure 3] This is a front view of the milling machine according to Embodiment 1. [Figure 4] This is an exploded assembly drawing of the milling machine according to Embodiment 1. [Figure 5] This is a cross-sectional view AA in Figure 2. [Figure 6] This is a perspective view of the milling machine of Embodiment 2. [Figure 7] This is an exploded assembly drawing of the milling machine according to Embodiment 2. [Figure 8] This is a cross-sectional view of Embodiment 2. [Modes for carrying out the invention]

[0011] The milling cutter of the present invention will be described in detail below based on embodiments with reference to the drawings. The milling cutter of this embodiment is a multi-edge specification milling cutter with an increased number of edges, and is particularly suitable for face milling cutters. It is particularly preferably used for light metal processing. In addition, in the present specification, the direction toward the workpiece in the rotation axis direction of the milling cutter is referred to as the tip direction, and the opposite of the tip direction is referred to as the rear end direction. Note that due to problems in creating drawings from 3D models, in the drawings, there may be lines that do not clearly appear on the surface of the actual product at the part where the curvature of the curved surface changes (for example, the grooves 113, the body side grooves 211 in FIGS. 1, 3, 4, and the parts corresponding to the grooves and body side grooves in FIGS. 6, 7, etc.).

[0012] In addition, the numerical range "x~y" described in this specification includes the lower limit x and the upper limit y within that range. And new numerical ranges can be constituted by arbitrarily combining these upper limit values, lower limit values, and 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 limit value and the lower limit value. For example, a range exceeding x can be adopted, or a range less than y can be adopted. Furthermore, the numerical values arbitrarily selected from within any of the above numerical ranges can be used as the upper and lower limit numerical values of the new numerical range.

[0013] The milling cutter of this embodiment has a blade part, a body, and fastening bolts. The blade part and the body are fixed so that the rear end surface of the blade body part constituting the blade part is in close contact with and abuts against the front end surface of the body. The fixation of both is performed by fastening bolts. The rotation axis of the fastening bolts is arranged to coincide with the rotation axes of the blade part and the body.

[0014] The blade part has a plurality of inserts and a blade body part to which those inserts are fixed. The inserts have a bottom edge and an outer peripheral edge provided with cutting edges. The material constituting the inserts is not particularly limited, but examples include being composed of cemented carbide, polycrystalline diamond, CBN, and other ceramics. In particular, the material can also be changed between the cutting edge and other parts. The number of inserts is not particularly limited.

[0015] When the tip is worn or damaged, the cutting edge can be removed from the body and replaced with a usable cutting edge to continue use. Replacing the cutting edge is easier than replacing or adjusting the tip. The removed cutting edge can be reground, repaired, or replaced to reproduce the tip.

[0016] The blade body part is generally a plate-like body and has a shape close to a disc as a whole. The material forming the blade body part is not particularly limited, but alloy tool steel is preferred. The thickness of the blade body part is preferably 4 mm or more, more preferably 5 mm or more, and even more preferably 6 mm or more. When the thickness increases, deformation of the blade body part can be suppressed, so the accuracy of machining using the milling cutter of the present embodiment can be improved.

[0017] The rear end face, which is the face of the blade body part that abuts against the body, is preferably able to be in close contact with the front end face of the body described later, and the rear end face and the front end face preferably have a complementary shape to enhance the close contact property. The rear end face and the front end face are particularly preferably flat. The part where close contact occurs between the rear end face of the blade body part and the front end face of the body is preferably near the part where the tip is fixed. Since the deflection of the blade body part can be suppressed by the close contact of the front end face of the body, the deflection of the part where the tip is fixed can be suppressed by making close contact near the part where the tip is fixed, and the machining accuracy can be improved.

[0018] The blade body part is provided with a cutting edge mounting hole penetrating in the thickness direction. The cutting edge mounting hole cooperates with the body mounting hole / cavity described later to accurately fix the cutting edge to the body. Details will be described together with the body mounting hole / cavity of the body described later.

[0019] Multiple tips are fixed to the outer circumference of the blade body. The tips can be fixed by methods such as brazing, welding, or adhesive bonding. The tips can be fixed with a straight or positive / negative helix angle depending on the workpiece material and application. Increasing the helix angle in the positive direction improves chip evacuation 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 axis of rotation, and these upper and lower limits can be combined arbitrarily. The tips can be either bottom cutting edges or outer cutting edges. The bottom cutting edges and outer cutting edges of the tips can have any rake angle.

[0020] There are no particular limitations on the arrangement of the multiple tips fixed to the outer circumference of the blade body. For example, they can be arranged in positions that are rotationally symmetrical with respect to the axis of rotation, or in uneven positions that are not rotationally symmetrical. It is preferable that grooves are formed in the blade body to match the areas where the tips are fixed.

[0021] When fixing the chip to the outer circumference 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, as this enables high-precision milling. In this specification, "runout" refers to the maximum runout width of the cutting edge when the blade is rotated once on the axis of rotation. The sum S is preferably 10 μm or less, and more preferably 5 μm or less.

[0022] The body has a tip portion to which the blade portion is fixed. The material used to form the body is not particularly limited, but alloy tool steel is preferred. The body can be formed in two or more parts, and each part can be formed from a different material. The tip portion has a tip surface to which at least a portion of the rear end surface of the blade body portion is fixed in a way that allows for tight contact and detachment.

[0023] The tip section has a body mounting hole / hole in the center of its tip surface. With the rear end surface of the blade body of the blade section in close contact with the tip surface of the tip section, a fastening bolt is inserted through the blade mounting hole. The inserted fastening bolt fastens and secures the blade body to the tip section. The fastening bolt has a shaft portion without threads between the threaded portion and the head. The head biases the blade body axially toward the rear end, pressing and securing the blade body toward the front end of the body so that its rear end face is in close contact with it. Since it is desirable that the head does not protrude toward the front end beyond the tip bottom edge of the blade, the shape of the blade body toward the front end is preferably such that the head is embedded. Considering the possibility of damage to the tip, it is preferable that the head does not protrude from the front end of the blade body.

[0024] When using countersunk bolts with countersunk heads as fastening bolts, a portion of the mounting hole for the blade body that does not come into close contact with the shaft can be tapered, widening towards the tip. The taper's inclination is preferably the same as that of the countersunk bolt. A larger head diameter is preferable because it increases the surface area that presses against the blade body, improving the contact between the blade body and the tip. Here, the portion of the head that presses against the blade body (pressing portion) is preferably approximately circular, and the preferred lower limit for the outer diameter of the pressing portion relative to the outer diameter of the blade is 40%, 50%, or 60%, while the preferred upper limit is 70%, 80%, or 90%. These lower and upper limits can be combined arbitrarily.

[0025] The fastening bolt can have a form in which the head and shaft are integrated, and this form is preferred, but a form in which the head is removable may also be adopted. In order to make the head removable, a thread can be formed on the side that connects to the head, which is the opposite side of the side that connects to the threaded part of the shaft, and a nut or a cap screw-like member formed to screw onto that thread can be attached to the head.

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

[0027] For example, the outer circumferential surface of the shaft, the inner circumferential surface of the blade mounting hole, and the body mounting hole / hole can be exemplified as a cylindrical shape or a part or all of the outer circumferential surface of a frustocone. A cylindrical shape is particularly preferable because it improves machining accuracy. When fastened, the mounting accuracy in the direction perpendicular to the rotation axis of the blade and body is determined by reducing the clearance between the outer circumferential surface of the shaft and the blade mounting hole / hole. An example of a clearance size is approximately 10 μm to 20 nm.

[0028] The diameters of the outer circumferential surface of the shaft in the fastened state may be the same or different at the portion in close contact with the inner circumferential surface of the blade mounting hole and the portion in close contact with the body mounting hole / hole. Furthermore, even in the portion of the outer circumferential surface of the shaft in the fastened state that is in close contact with the inner circumferential surface of the blade mounting hole, there may be portions with different diameters at different points along the axial direction. Similarly, even in the portion of the outer circumferential surface of the shaft in the fastened state that is in close contact with the inner circumferential surface of the body mounting hole / hole, there may be portions with different diameters.

[0029] Furthermore, if the diameters of the outer circumferential surface of the shaft that are in close contact with the blade mounting hole and the body mounting hole / hole are different, it is preferable to make the diameters the same, or to change them so that they gradually decrease in the direction in which the fastening bolt is inserted into the blade mounting hole and the body mounting hole / hole, or to combine these methods. Furthermore, the inner surfaces of the blade mounting holes and body mounting holes / holes may contact the outer surface of the shaft over their entire surface, partially, or at a single point. They may not even contact at a single point. The fit tolerances between the shaft of the fastening bolt and the blade mounting holes and body mounting holes / holes restrict the movement of the fastening bolt in a direction perpendicular to the axial direction, thereby ensuring mounting accuracy between the blade and the body.

[0030] It is desirable that the tip surface be in close contact with the blade body, particularly near the outer circumference of the blade body. Furthermore, it is desirable that the tip surface be provided so as to be in close contact with 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, and if the rear end surface has irregularities, the tip surface has irregularities that allow it to be in close contact with those irregularities. The shape of these irregularities can also act as an anti-rotation mechanism by making the rear end surface and the tip surface unable to rotate relative to each other. Specifically, an example of an anti-rotation mechanism formed as a complementary shape between the front and rear ends is a protruding member such as a pin provided on either the front or rear end, and an anti-rotation hole on the other end that is sized to allow the protruding member to be inserted. When the protruding member is inserted into the anti-rotation hole, the relative rotation between the blade and the body is restricted. Another anti-rotation mechanism that can be used is a removable key.

[0031] The shape of the outer circumference of the tip (outer circumference of the tip) is preferably such that its projected shape in the direction of the rotation axis is the same as that of the blade body in the direction of the rotation axis. Specifically, the outer diameter is 100 / 100 to 92 / 100, with the outer diameter of the blade being the reference (100 / 100). In particular, the shape of the tip surface is also preferably such that its outer diameter is 100 / 100 to 92 / 100, with the outer diameter of the blade being the reference. The lower limit of the outer diameter of the tip and the tip surface is preferably 96 / 100, respectively. By making the body (tip) have an outer diameter similar to that of the blade body, vibrations caused by the rotation of the blade body can be suppressed. The outer diameter of the blade body is not particularly limited, but can be approximately 25 mm to 50 mm.

[0032] Preferably, the outer circumference of the tip has a body groove that connects to the groove of the blade body, which is in close contact with it. Chips generated by machining are discharged through the groove of the blade body, and then, if present, through the body groove. 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 of the blade body.

[0033] The body can have a cutting fluid supply passage formed in the body side groove, through which an outlet for supplying cutting fluid is opened. The diameter of the outlet opening 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 within the body side groove. In particular, it is formed to open in a location adjacent to the tip surface. The cutting fluid supply passage is formed in a direction as close to parallel as possible with the rotation axis so that the direction of cutting fluid discharge is directed toward the tip of the rotation axis, so that cutting fluid is discharged from the outlet toward the tip of the rotation axis. If the length in the rotation axis direction of the milling cutter of this embodiment is insufficient, the cutting fluid supply passage may be formed in a bent shape. If there are multiple body side grooves connected to the grooves corresponding to the part where the tip is fixed, it is preferable that the outlet opens in all of those body side grooves.

[0034] If the tip fixed to the blade body has a positive helix angle (axial rake angle), a second outer peripheral cutting edge can be provided on the outer circumference behind the tip. The second outer peripheral cutting edge has a negative helix angle. Cutting with an outer peripheral cutting edge with a positive helix angle biases the chip towards the rear end, which can cause burrs. These burrs can be removed by biasing the chip towards the tip with the second outer peripheral cutting edge with a negative helix angle. The second outer peripheral cutting edge is attached to a second tip. The second tip may be fixed to the rear end of the blade body or to the front end of the body. Furthermore, the second cutting edge may be formed by fixing it to a second blade body, which is a different component from the blade body and the body.

[0035] The second blade body preferably has the same projected shape in the direction of the rotation axis as the main blade body, and its thickness is also preferably about the same. In many cases, fewer second tips than the tips on the blade are sufficient.

[0036] (Embodiment 1) As shown in Figures 1-5, the milling cutter 1 of this embodiment has a cutting edge 10 and a body 20. The cutting edge 10 has a blade body 11 and 12 chips 12. The cutting edge 10 is fastened to the body 20 with fastening bolts 30. The fastening bolts 30 have hexagonal sockets 31 in their heads 34. The fastening bolts 30 allow for easy attachment and detachment, and no further adjustment is required. Therefore, even if the chips 12 wear out or chip, machining can be immediately resumed by replacing the entire cutting edge 10. Since only the cutting edge 10 is replaced, the cost is lower than when a spare milling cutter is prepared and the entire milling cutter is replaced.

[0037] The milling cutter 1 of this embodiment has a rotation axis that extends from the center of Figure 2 in the direction of the front and back of the paper. The front direction in Figure 2 and the upward direction in Figure 3 are the front end directions, and the back direction in Figure 2 and the downward direction in Figure 3 are the rear end directions.

[0038] The blade body 11 is made of alloy tool steel. The blade body 11 has a thickness of 5 mm, a diameter of 50 mm, and is roughly disc-shaped. A blade mounting hole 11a is formed in the center, and two anti-rotation holes 11b are formed around the blade mounting hole 11a into which the tip of an anti-rotation pin 214, which serves as an anti-rotation mechanism, can be inserted.

[0039] The blade mounting hole 11a has an inner diameter such that its inner circumferential surface is in close contact with the outer circumferential surface of the shaft portion 38 of the fastening bolt 30. The fastening bolt 30 has a countersunk head 34, a threaded portion 36, and a shaft portion 38 connecting the head 34 and the threaded portion 36. A recess is formed on the tip side of the blade body portion 11 so that the countersunk head 34 fits into it. The head 34 is recessed to the extent that it does not protrude from the tip side of the tip portion 21. The outer diameter of the head 34 is 32 mm, which is 64% of the outer diameter of the blade body portion 11 of the blade portion 10 (50 mm). 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 and an outlet 32a that opens toward the rear end of the shaft portion 38 at a position where the diameter is slightly reduced.

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

[0041] The tip 12 has a bottom cutting edge 121 and an outer cutting edge 122. Chamfering edges are sharpened at the corners of the bottom cutting edge 121 and the outer cutting edge 122. The tip 12 is fixed to the tip seat 112 such that the bottom cutting edge 121 protrudes toward the tip of the blade body 11 and the outer cutting edge 122 protrudes toward the outer diameter of the blade body 11. Fixing to the tip seat 112 can be done by brazing. The tip 12 is fixed such that the outer cutting edge 122 has a positive helix angle. The bottom cutting edge 121 has a positive rake angle.

[0042] The outer shapes of the front and rear surfaces of the blade body 11 have the same projected shape in the direction of the rotation axis and are parallel planes in a direction perpendicular to the rotation axis. The rear surface of the blade body 11 can be in close contact with the front surface of the front part 21 of the body 20, thus suppressing deformation of the blade body 11. Therefore, the accuracy of the rear surface of the blade body 11 and the front surface of the front part 21 directly affects the machining accuracy of the milling cutter, so they are manufactured to minimize runout of the front and rear surfaces. Specifically, the sum S of the runout of the bottom cutting edge 121 attached to the chip 12 and the runout of the rear surface is set to be 5 μm or less. In addition, because the blade body 11 is thick, deflection due to the effects of external forces and thermal fluctuations is less likely to occur, resulting in higher machining accuracy.

[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 circumferential surface of the part where the shaft portion 38 of the fastening bolt 30 is located is in close contact with the shaft portion 38. The threaded portion 36 of the fastening bolt 30 is screwed into the arbor of the processing device. The base portion 22 has a substantially cylindrical outer shape and has a fitting groove 222 cut out on the rear end side so that it can be connected to the processing device. It is also possible to form a threaded portion that can be fastened with the threaded portion 36 of the fastening bolt 30 inside the body mounting hole 21a 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, and deflection of the blade body portion 11 during cutting can be suppressed. From the viewpoint of suppressing deflection during cutting, it is particularly preferable that the tip surface has a projection shape 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] A body side groove 211 is formed on the outer circumference of the tip portion 21, extending from a groove 113 formed in the blade body portion 11 with the same cross-sectional shape as the groove 113. The body side groove 211 is slightly twisted so as it advances clockwise towards the tip. Each of the body side grooves 211 has a cutting fluid outlet 213a. A cutting fluid supply port 213b is opened inside the body 20, and a supply passage 213 is formed that connects each cutting fluid supply port 213b to the cutting fluid outlet 213a. The cutting fluid is supplied from the inlet 32b of the fastening bolt 30 through the outlet 32a, and then through the gap provided between the threaded 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) The milling cutter of this embodiment will be described based on the drawings. The milling cutter of this embodiment is composed of generally the same elements as the milling cutter of Embodiment 1, and equivalent components are given the same reference numeral preceded by "A".

[0047] As shown in Figure 6, the milling cutter A1 of this embodiment has a cutting edge A10, a body A20, and fastening bolts 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 A21, a base A22, and a shank A23 on the rear end side of the base A22. This milling cutter is attached to a machine tool via the shank A23. [Explanation of Symbols]

[0049] 1. A1...Milling cutter 10. A10...Cutting edge 11...Blade body 11a…Blade mounting hole 12…Chip 112…Chip seat 113…Groove 121...Bottom blade 122...Outer blade 20, A20...Body 21, A21...Tip portion 21a...Body mounting hole 22, A22...Base portion A23...Shank 211...Body side groove 213...Supply channel 213a…Cutting fluid discharge port 213b…Cutting fluid supply port 214…Pin 222... Fitting groove 30, A30... Fastening bolt 32... Cutting fluid supply channel 32a... Outlet 32b... Inlet 34... Head 36... Threaded part 38... Shaft

Claims

1. A blade portion having multiple chips and a blade body portion which is a plate-like body having blade mounting holes that penetrate in the thickness direction and are fixed to the outer circumference of the multiple chips, The rear end surface of the blade body is provided with a tip surface that can be fixed in close contact and detachably, and the tip portion has a body mounting hole / hole opening in the center of the tip surface, and the outer diameter is 100 / 100 to 92 / 100 with the outer diameter of the blade portion as the reference (100 / 100), and the body is rotatable around the axis of rotation, A fastening bolt in which at least a portion of the outer circumferential surface of the shaft portion between the head and the threaded portion is inserted into the inner circumferential surface of the blade mounting hole and the body mounting hole / hole, and when fastened, the outer circumferential surface of the shaft portion is shaped to be in close contact with the inner circumferential surface of the blade mounting hole and the body mounting hole / hole, It has, The aforementioned rear end surface and the aforementioned front end surface are flat and in close contact over their entire surface. A pin-like projection member is attached to one of the front end surface and the rear end surface, and the other front end surface and the rear end surface have a rotation-preventing hole of a size into which the projection member can be inserted. The thickness of the blade body is 4 mm or more. The fastening bolt is a countersunk bolt, and a tapered seat corresponding to the head of the fastening bolt is formed in the tip-side portion of the blade mounting hole, which widens in diameter towards the tip. The pressing portion of the fastening bolt, which is the part that presses against the blade body, is substantially circular, and the outer diameter of the pressing portion is 40% or more and 90% or less of the outer diameter of the blade. Milling machine.

2. A groove is formed on the outer circumference of the blade body portion, corresponding to the position of the tip. A body side groove is formed on the outer circumference of the tip portion, which connects to the groove when the blade body portion is in close contact with it. The milling cutter according to claim 1.

3. The milling cutter according to claim 1 or 2, wherein the body has a cutting fluid supply passage formed that connects a cutting fluid supply port opening at the rear end and a cutting fluid injection port opening at the front end.

4. The blade mounting hole and the body mounting hole / hole are cylindrical in shape and have the same or different diameters. The outer circumferential surface of the shaft portion of the fastening bolt is such that the blade body portion is fastened to the tip portion. The milling cutter according to claim 1 or 2, which is inserted with a clearance between the entire inner surface of the blade mounting hole and the inner surface of the body mounting hole / hole, respectively, to achieve the required assembly accuracy.

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