JP2015104781A - Mounting method for blade tip exchange type cutting tool set, tool body, and cutting inert - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high-precision cutting work to be stably carried out in spite of the use of a plurality of kinds of cutting inserts with different outer diameter precisions.SOLUTION: A convex curved surface 17a and a plane part 17b retreated inside of the convex curved surface 17a in an insert radial direction are formed in the outer peripheral surface 17 of a cutting insert 3. A plurality of kinds of cutting inserts 3 have different retreating amounts Dof the plane parts 17b with respect to the convex curved surface 17a. A support wall surface 7a of an insert mounting seat 4 abutted to the outer peripheral surface 17 of a cutting insert 3 comprises a first support part 11 formed in a concave curved surface form in accordance with the shape of the convex curved surface 17a and a second support part 12 formed in a planar form in accordance with the shape of the plane part 17b and projected from the first support part 11. A plurality of kinds of cutting inserts 3 include first cutting inserts having larger retreating amounts than projection amounts H of second support part 12 with respect to the support part 11 and second cutting inserts 3B having smaller retreating amounts Dthan the projection amounts H.

Description

  In the present invention, a predetermined cutting insert selected from a plurality of types of disc-shaped cutting inserts is detachably mounted on an insert mounting seat formed on the outer periphery of the tip of a tool body that rotates about a tool axis. The present invention relates to a cutting edge set cutting tool set, a tool body, and a mounting method for a cutting insert.

DESCRIPTION OF RELATED ART Conventionally, what is shown, for example in the following patent document 1 is known as a blade-tip-exchange-type cutting tool such as a blade-tip-exchange-type milling tool used for milling (rolling) of a work material made of a metal material.
In this cutting edge-exchangeable cutting tool, a disc-shaped cutting insert (round piece insert) is detachably mounted on an insert mounting seat formed on the outer periphery of the tip of a tool body that rotates about the tool axis.

  The cutting insert of Patent Document 1 has front and back surfaces (a circular surface facing one of the insert axial directions and an octagonal surface facing the other) of the cutting insert, and an insert radial direction perpendicular to the insert axial line. An outer peripheral surface facing the outside of the circular surface, and the circular surface facing the front in the tool rotation direction along the tool axis of the front and rear surfaces of the front and rear surfaces with the cutting insert mounted on the insert mounting seat. And a cutting edge forming an intersecting ridge line therebetween.

  Further, in FIG. 2 and the like of Patent Document 1, the outer peripheral surface includes a conical portion (first shape) that gradually decreases in diameter from the circular surface (upper surface 11) toward the octagonal surface (lower surface 12) along the insert axial direction. 1 portion 13a), a portion that is disposed closer to the octagonal surface than the conical portion and has an outer diameter smaller than that of the conical portion, and has a regular octagonal cross section perpendicular to the insert axis 2 portions 13b).

Further, in FIG. 3 and the like of Patent Document 1, the insert mounting seat has a concave conical wall surface that is in contact with the conical portion of the outer peripheral surface of the cutting insert and supports the cutting insert from the insert radial direction. (Concave surface 35) and a corner portion of a portion in which a cross section perpendicular to the insert axis forms a regular octagon (see corner 23 of second portion 13b of cutting insert 10, see FIG. 1 of Patent Document 1, etc.) And a wall surface (lower portion 37) for preventing the cutting insert from rotating.
Then, the cutting insert is fixed to the insert mounting seat in a state where the conical portion (flank) on the outer peripheral surface of the cutting insert is in contact with the concave conical wall surface of the insert mounting seat. ing.

Japanese Patent No. 3819428

However, the conventional cutting edge exchange type cutting tool has the following problems.
In other words, as a disc-shaped cutting insert, the flank on the outer peripheral surface is often used with sintered skin (without polishing) (ISO class M insert), or the flank is on the entire circumference. There are a plurality of types depending on the outer diameter accuracy, such as cutting inserts (H class inserts of ISO classification) that are polished over a wide range. Depending on the type and application of the cutting process, the same tool body may be used to perform cutting with an M-class insert and cutting with an H-class insert.

Therefore, for example, when an M class insert whose outer diameter accuracy is inferior to that of a class H insert is mounted on an insert mounting seat, the conical portion (flank) of the class M insert and the insert mounting seat When the concave conical wall surface is brought into contact with each other, the concave conical wall surface may be partially worn or deformed.
If such wear or deformation occurs, the mounting state of the cutting insert to be mounted next on the insert mounting seat will become unstable, or the cutting edge position will not be determined accurately, so that the cutting accuracy will be sufficient. It becomes difficult to secure.

  The present invention has been made in view of such circumstances, and according to the outer diameter accuracy of the disc-shaped cutting insert, the support wall surface of the insert mounting seat with which the outer peripheral surface of the cutting insert abuts can be selected. Thus, there is provided a cutting edge replaceable cutting tool set, a tool body, and a cutting insert mounting method capable of stably performing high-precision cutting while using a plurality of types of cutting inserts having different outer diameter accuracy. It is intended to provide.

In order to solve such problems and achieve the above object, the present invention proposes the following means.
That is, according to the present invention, a predetermined cutting insert selected from a plurality of types of disc-shaped cutting inserts is detachably mounted on an insert mounting seat formed on the outer periphery of the tip of a tool body that rotates around the tool axis. The cutting insert is a cutting tool set to be replaced, the cutting insert is a pair of circular surfaces facing the insert axial direction of the cutting insert, and an outer peripheral surface facing the outer side of the insert radial direction orthogonal to the insert axial line, And at least one of the pair of circular surfaces and a cutting edge forming a cross ridge line with the outer peripheral surface, and the outer peripheral surface has a curved shape that appears in a cross section perpendicular to the insert axis And a shape appearing in a cross section perpendicular to the insert axis is rectilinear and recedes inwardly in the insert radial direction from the convex curved surface portion. A plurality of types of cutting inserts are different from each other, and the insert mounting seat has the above-mentioned cutting inserts of the cutting inserts. A supporting wall surface that is in contact with an outer peripheral surface is formed, and the supporting wall surface is disposed opposite to the convex curved surface portion, and is formed in a concave curved surface shape corresponding to the shape of the convex curved surface portion. And a flat surface corresponding to the shape of the flat portion, and projecting toward the cutting insert attached to the insert mounting seat from the first support portion. A plurality of types of the cutting inserts, wherein the retraction amount is larger than the protrusion amount by which the second support portion protrudes with respect to the first support portion; , The retraction amount is And a small second cutting insert than serial protrusion amount, characterized in that it is included.
Moreover, the tool main body which concerns on this invention is used for the blade-tip-exchange-type cutting tool set mentioned above.
The present invention also includes a tool body that rotates around a tool axis, and a disc-shaped cutting insert that is selected from a plurality of types and mounted on an insert mounting seat formed on the outer periphery of the tip of the tool body. A cutting insert mounting method for mounting the cutting insert on the insert mounting seat of the blade-tip-exchange-type cutting tool set provided, wherein the cutting insert has a pair of circular surfaces facing the insert axial direction of the cutting insert, An outer peripheral surface that faces the outer side of the insert radial direction orthogonal to the insert axis, at least one of the pair of circular surfaces, and a cutting edge that forms a cross ridge line between the outer peripheral surface, and the outer periphery A convex curved surface portion having a curved shape in a cross section perpendicular to the insert axis, and a straight shape in a cross section perpendicular to the insert axis. In addition, a flat portion that recedes inward in the insert radial direction from the convex curved surface portion is formed, and a retreat amount by which the flat portion recedes with respect to the convex curved portion is determined between a plurality of types of the cutting inserts. Different from each other, a support wall surface that is in contact with the outer peripheral surface of the cutting insert is formed on the insert mounting seat, and the support wall surface is opposed to the convex curved surface portion, and the convex curved surface portion A first support portion formed in a concave curved surface shape corresponding to the shape, and arranged to be opposed to the flat portion, and formed in a flat shape corresponding to the shape of the flat portion, than the first support portion A second support portion that protrudes toward the cutting insert mounted on the insert mounting seat, and the retraction amount of the plurality of types of cutting inserts is greater than the second support portion with respect to the first support portion. Support part protrudes When mounting the first cutting insert larger than the protrusion amount on the insert mounting seat, the convex curved portion of the first cutting insert is brought into contact with the first support portion, and the retraction amount is When the second cutting insert smaller than the protrusion amount is mounted on the insert mounting seat, the flat portion of the second cutting insert is brought into contact with the second support portion.

This cutting edge replaceable cutting tool set can be used by attaching a plurality of types of cutting inserts to one tool body.
Specifically, when a first cutting insert having a large retraction amount is selected from a plurality of types of cutting inserts and mounted on the insert mounting seat, the convex curved surface portion on the outer peripheral surface of the first cutting insert is The flat surface portion on the outer peripheral surface of the first cutting insert is in contact with the concave curved first support portion on the support wall surface of the insert mounting seat, and the flat second support portion on the support wall surface of the insert mounting seat It is arrange | positioned away from.
In addition, when a second cutting insert having a small retraction amount is selected from a plurality of types of cutting inserts and mounted on the insert mounting seat, the flat portion on the outer peripheral surface of the second cutting insert is inserted into the insert mounting. The convex curved surface portion on the outer peripheral surface of the second cutting insert is separated from the concave curved first support portion on the support wall surface of the insert mounting seat, while being in contact with the planar second support portion on the support wall surface of the seat. Arranged.

Thus, depending on the type of cutting insert, the convex curved surface portion of the outer peripheral surface of the cutting insert is brought into contact with the support wall surface (first support portion) of the insert mounting seat, or the flat surface portion is supported on the support wall surface (second support). Part) can be selected. Thereby, the following effects can be obtained.
That is, among a plurality of types of cutting inserts, for example, an ISO class H-class insert in which the outer diameter accuracy of the convex curved surface portion (flank) of the outer peripheral surface is ensured by polishing or the like is used as the first cutting insert, When the first cutting insert is mounted on the insert mounting seat, the convex curved surface portion of the outer peripheral surface of the cutting insert is brought into contact with the support wall surface of the insert mounting seat. In other words, since the outer diameter accuracy of the first cutting insert is secured, the convex curved surface portion and the support wall surface can be spotted by bringing the convex curved surface portion into contact with the support wall surface (first support portion). Without touching a wide area, the contact area is secured. As a result, the cutting insert can be stably mounted on the insert mounting seat, and the cutting blade can be positioned with high accuracy, and high-quality cutting can be stably performed.

  On the other hand, among a plurality of types of cutting inserts, for example, the convex curved surface portion (flank surface) of the outer peripheral surface is a sintered skin (no polishing processing), and the M class of ISO classification whose outer diameter accuracy is inferior to the H class insert. When an insert or the like is used as the second cutting insert and the second cutting insert is mounted on the insert mounting seat, the flat portion of the outer peripheral surface of the cutting insert is brought into contact with the support wall surface of the insert mounting seat. . In other words, the second cutting insert has a low outer diameter accuracy, but by bringing the flat portion into contact with the support wall surface (second support portion), the flat surface portion and the support wall surface do not hit each other over a wide range. Thus, a contact area is ensured. Thereby, the cutting insert can be stably mounted on the insert mounting seat, and the cutting can be stably performed with the intended processing accuracy.

  In the present invention, “a predetermined cutting insert selected from a plurality of types of disc-shaped cutting inserts is detachably attached to the insert mounting seat” basically means that the above-described first. It is assumed that one of the first and second cutting inserts is mounted on the insert mounting seat. However, the present invention is not limited to this. For example, when a plurality of insert mounting seats are provided, one of these insert mounting seats is mounted with a class H insert having a high cutting edge position accuracy as a finishing blade. In addition, a coarse M class insert may be mounted on the other insert mounting seat.

  As described above, according to the cutting edge set cutting tool set, the tool body, and the cutting insert mounting method of the present invention, the insert with which the outer peripheral surface of the cutting insert abuts according to the outer diameter accuracy of the disc-shaped cutting insert. The supporting wall surface of the mounting seat can be selected, and thus high-precision cutting can be stably performed while using a plurality of types of cutting inserts having different outer diameter accuracy.

  In the cutting edge set cutting tool set of the present invention, the convex curved surface portion of the first cutting insert may be a polished surface.

  In this case, the outer diameter accuracy of the convex curved surface portion on the outer peripheral surface of the first cutting insert can be reliably increased, and the above-described operational effects become more remarkable.

  Further, in the cutting edge replaceable cutting tool set of the present invention, the flat surface portion on the outer peripheral surface of the cutting insert may be formed such that a part of the convex curved surface portion is cut out.

  In this case, the shape of the cutting insert is simplified without being complicated, and the convex curved surface portion and the flat surface portion can be easily formed on the outer peripheral surface of the cutting insert. Moreover, since the outer peripheral wall thickness of the cutting insert can be sufficiently secured, it is easy to secure the insert rigidity.

  According to the blade-tip-exchangeable cutting tool set, the tool body, and the cutting insert mounting method of the present invention, the insert mounting seat with which the outer peripheral surface of the cutting insert abuts according to the outer diameter accuracy of the disc-shaped cutting insert. A support wall surface can be selected, and thereby high-precision cutting can be stably performed while using a plurality of types of cutting inserts having different outer diameter accuracy.

It is a perspective view which shows an example of the blade-tip-exchange-type cutting tool set which concerns on one Embodiment of this invention. It is a side view of the blade-tip-exchange-type cutting tool set of FIG. FIG. 2 is a side view (half-sectional view) of the cutting edge replaceable cutting tool set of FIG. It is the front view (bottom view) which looked at the blade-tip-exchange-type cutting tool set of FIG. 1 from the tool front end side. It is a perspective view which expands and shows the insert attachment seat in the tool main body of the blade-tip-exchange-type cutting tool set of FIG. It is the (a) top view and the (b) side view which show the 1st cutting insert among the multiple types of cutting insert with which the blade-tip-exchange-type cutting tool set of FIG. 1 is equipped. It is the (a) top view and (b) side view which show the 2nd cutting insert among the multiple types of cutting insert with which the blade-tip-exchange-type cutting tool set of FIG. 1 is equipped. It is the figure which looked at the cutting insert with which the insert mounting seat was mounted | worn toward the back of the tool rotation direction. It is AA cross section of FIG. 8, and is sectional drawing which shows the state in which the 1st cutting insert was mounted | worn with the insert mounting seat. It is AA cross section of FIG. 8, and is sectional drawing which shows the state with which the 2nd cutting insert was mounted | worn with the insert mounting seat. It is a BB section of Drawing 8, and is a sectional view showing the state where the 1st cutting insert was installed in the insert mounting seat. FIG. 9 is a cross-sectional view taken along the line B-B of FIG. 8 and showing a state in which the second cutting insert is mounted on the insert mounting seat. It is a figure explaining the state where the cutting insert with which the insert mounting seat was mounted | worn is hitting.

Hereinafter, a method for attaching a cutting insert 3 to a cutting edge set-type cutting tool set 1 according to an embodiment of the present invention, a tool body 2 thereof, and an insert mounting seat 4 of the tool body 2 will be described with reference to the drawings.
The blade-tip-exchangeable cutting tool set 1 of the present embodiment is a blade-tip-exchangeable milling tool set used for, for example, milling (working) of a workpiece made of a metal material such as a heat-resistant alloy.

As shown in FIG. 1 to FIG. 4, the cutting edge replaceable cutting tool set 1 includes a tool body 2 formed of steel or the like, and a disk-shaped cutting insert 3 formed of a hard material such as cemented carbide. , And a plurality of types of cutting inserts 3 are provided, and a predetermined cutting insert 3 selected from them is mounted on the tool body 2 and used for cutting.
That is, this cutting edge replaceable cutting tool set 1 is selected from a plurality of types of disc-shaped cutting inserts 3 on the insert mounting seat 4 formed on the outer periphery of the tip of the tool body 2 rotating around the tool axis O. The predetermined cutting insert 3 is detachably mounted. These cutting inserts 3 are so-called round piece inserts having an annular cutting edge 5, and the cutting edge 5 is attached to the insert mounting seat 4 in the tool axis O direction of the tool body 2. It protrudes toward the tip end side and the outer side in the tool radial direction.

The cutting edge set type cutting tool set 1 has a base end portion of a tool body 2 attached to a main shaft of a machine tool (not shown) and rotated in a tool rotation direction T around a tool axis O to Used for cutting.
Here, in this specification, the insert mounting seat 4 side along the tool axis O direction of the tool body 2 is referred to as the tool tip side or simply the tip side (lower left direction in FIG. 1), and the insert mounting along the tool axis O direction. The side opposite to the seat 4 (the main spindle side of the machine tool) is referred to as the tool base end side or simply the base end side (upper right direction in FIG. 1). A direction perpendicular to the tool axis O is referred to as a tool radial direction, and a direction around the tool axis O is referred to as a tool circumferential direction. Of the tool circumferential directions, the direction in which the tool body 2 is rotated at the time of cutting is referred to as the front of the tool rotation direction T (or simply the tool rotation direction T), and the direction toward the opposite side from the front of the tool rotation direction T. It is called the rear of the tool rotation direction T. In addition, a direction orthogonal to the insert axis C of the cutting insert 3 is referred to as an insert radial direction, and a direction around the insert axis C is referred to as an insert circumferential direction.

  In FIG. 1, a tool mounting hole 2 a extending along the tool axis O is formed in the tool body 2 so as to penetrate the tool body 2. Further, a key groove 2b extending from the opening edge of the tool mounting hole 2a toward the outer side in the tool radial direction is formed on the end surface of the tool body 2 facing the tool base end side. The tool body 2 is attached to the tip end portion of the spindle by a fastening member such as a bolt inserted through the tool mounting hole 2a in a state where the key groove 2b is fitted to a key provided at the tip end portion of the spindle of the machine tool.

  A plurality of chip pockets 6 having a concave shape are formed in the outer peripheral portion of the tool body 2 at intervals in the circumferential direction of the tool so as to be cut out from the outer peripheral portion of the tip. In these chip pockets 6, insert mounting seats 4, to which the cutting insert 3 is detachably mounted, are formed on the wall surface that is located behind the tool rotation direction T and faces the front of the tool rotation direction T, respectively. The insert mounting seat 4 is formed to be recessed rearward in the tool rotation direction T from the portion other than the insert mounting seat 4 on the wall surface.

  Although not particularly illustrated, a coolant circulation hole for circulating coolant (cutting oil) supplied from the main spindle of the machine tool may be formed inside the tool body 2. When the coolant circulation hole is formed in the tool body 2, the coolant circulation hole is branched into a plurality at the tip side portion inside the tool body 2, and is opened in each chip pocket 6 toward each insert mounting seat 4. The

  In FIG. 5, the insert mounting seat 4 has a mounting surface 4a facing forward in the tool rotation direction T, a peripheral wall 4b rising from a peripheral portion of the mounting surface 4a, and a mounting surface 4a. Possible screw holes 4c are formed.

The mounting surface 4a is formed corresponding to the shape of a seating surface 16 to be described later of the cutting insert 3 (in a shape capable of surface contact with the seating surface 16), and has a circular surface shape in the illustrated example.
In the side view of the tool body 2 shown in FIG. 2 (side view of the insert mounting seat 4), the mounting surface 4a extends in the vertical direction in FIG. 2 and is on the tool tip side (lower side in FIG. 2). As it goes, it gradually inclines toward the front of the tool rotation direction T (left side in FIG. 2). This also imparts a positive (positive) axial rake angle to the cutting insert 3 seated on the mounting surface 4a. However, the present invention is not limited to this, and in FIG. 2, the mounting surface 4 a may be gradually inclined toward the rear (right side in FIG. 2) in the tool rotation direction T as it goes to the tool tip side. It may be formed along the axis O (so as to be parallel).

  Further, in the bottom view of the tool body 2 shown in FIG. 4 (the bottom view of the insert mounting seat 4), the mounting surface 4a is formed along the tool radial direction. However, the present invention is not limited to this. In FIG. 4, the attachment surface 4 a may be gradually inclined forward or backward in the tool rotation direction T toward the outside in the tool radial direction.

In FIG. 5, the peripheral wall 4 b rises from the peripheral portion on the tool base end side of the mounting surface 4 a toward the front in the tool rotation direction T and extends along the tool radial direction, and the tool radial direction of the mounting surface 4 a From the inner peripheral edge of the mounting surface 4a and the wall surface 7b extending along the tool axis O direction and positioned between the wall surfaces 7a and 7b. A wall surface 7c that rises forward in the tool rotation direction T and gradually inclines toward the outer side in the tool radial direction as it goes toward the tool base end side.
In the peripheral wall 4 b of the insert mounting seat 4, the wall surfaces 7 a and 7 b are spaced apart from each other and are “supporting wall surfaces” that come into contact with the outer peripheral surface 17 of the cutting insert 3. The cutting insert 3 is disposed away from the outer peripheral surface 17 without contacting the outer peripheral surface 17.

  The support wall surface (wall surfaces 7a, 7b) of the insert mounting seat 4 is formed in a flat shape with the first support portion 11 formed in a concave curved surface shape, and is attached to the insert mounting seat 4 rather than the first support portion 11. And a second support portion 12 protruding toward the cutting insert 3. Specifically, on the support wall surfaces 7a and 7b, a second support portion 12 and a first support portion 11 are formed in this order from the mounting surface 4a toward the front in the tool rotation direction T, respectively. In the illustrated example, the first support portion 11 is disposed at the front end portion of the peripheral wall 4 b of the insert mounting seat 4 in the tool rotation direction T.

  The first support portions 11 of the support wall surfaces 7a and 7b are formed to have the same curvature and extend along the central axis of the screw hole 4c so as to be positioned on the same virtual circumference, And it arrange | positions in the same position along the said central-axis direction. In addition, the second support portions 12 of the support wall surfaces 7a and 7b are arranged so as to be in a vertical positional relationship with each other. Specifically, the second support portion 12 of the support wall surface 7a is along the tool radial direction. On the other hand, the second support portion 12 of the support wall surface 7b extends along the tool axis O direction.

  And the 1st support part 11 of support wall surface 7a, 7b is oppositely arranged to the convex curve part 17a (specifically flank part in the convex curve part 17a) mentioned later among the outer peripheral surfaces 17 of the cutting insert 3. The concave curved surface corresponding to the shape of the convex curved surface portion 17a (which can come into surface contact with the convex curved surface portion 17a) is formed. Further, the second support portion 12 of the support wall surfaces 7a and 7b is disposed to face a flat portion 17b described later on the outer peripheral surface 17 of the cutting insert 3, and corresponds to the shape of the flat portion 17b (on the flat portion 17b). It is formed in a flat shape that allows surface contact.

The first support of the support wall surface 7a in a sectional view along the central axis of the screw hole 4c of the insert mounting seat 4 shown in FIG. 9 and FIG. 10 (a sectional view perpendicular to the direction around the central axis of the screw hole 4c). The part 11 and the second support part 12 are gradually inclined toward the tool base end side (upper side in FIGS. 9 and 10) toward the front of the tool rotation direction T (left side in FIGS. 9 and 10).
11 and 12, the first support portion 11 and the second support portion 12 of the support wall surface 7b are arranged in front of the tool rotation direction T (in the cross-sectional view along the central axis of the screw hole 4c of the insert mounting seat 4 shown in FIGS. 11 and 12 gradually inclines toward the inner side (left side in FIGS. 11 and 12) in the tool radial direction.

The first support portion 11 and the second support portion 12 of the support wall surfaces 7a and 7b extend in parallel with each other and the screw hole 4c in a cross-sectional view along the central axis of the screw hole 4c shown in FIGS. The inclination angles with respect to the central axis are equal to each other. In the cross-sectional view, the first support portion 11 and the second support portion 12 of the support wall surfaces 7a and 7b extend non-parallel to each other and may have different inclination angles with respect to the central axis of the screw hole 4c. Good. Specifically, in the cross-sectional view, the first support portion 11 extends so as to be parallel to a convex curved surface portion 17 a of the cutting insert 3 described later, and the second support portion 12 is a flat portion of the cutting insert 3. The convex curved surface portion 17a and the flat surface portion 17b of the cutting insert 3 extend non-parallel to each other in the cross-sectional view (substantially equivalent to the cross-sectional view along the insert axis C). If there is, the first and second support portions 11 and 12 of the insert mounting seat 4 also extend non-parallel to each other in this sectional view.
Here, the symbol H shown in FIGS. 9 to 12 indicates the second support for the first support portion 11 along the direction orthogonal to the first support portion 11 and the second support portion 12 in the cross-sectional view. This represents the amount of protrusion from which the portion 12 protrudes (specifically, the maximum value of the amount of protrusion that changes around the central axis of the screw hole 4c).

  Further, in the support wall surfaces 7a and 7b, groove portions 13 are formed between the first support portion 11 and the second support portion 12, respectively. Further, a loose portion 14 is formed between the second support portion 12 and the mounting surface 4a. The groove portion 13 and the thinning portion 14 extend so as to extend around the central axis of the screw hole 4c.

The screw hole 4c has a female screw portion whose inner peripheral surface is subjected to female screw processing, and the screw hole 4c on the mounting surface 4a will be described later on the cutting insert 3 mounted on the insert mounting seat 4. It is arranged at a position facing the mounting hole 18.
Specifically, in the present embodiment, the screw hole 4c is disposed at a position communicating with the mounting hole 18, but the central axis (not shown) of the screw hole 4c is the central axis (insert axis C) of the mounting hole 18 of the cutting insert 3. On the other hand, the screw hole 4c and the mounting hole 18 are not coaxial with each other.

As shown in FIGS. 6A, 6B, 7A, 7B, and 8, the cutting insert 3 has a pair of circular surfaces 15 facing both sides of the cutting insert 3 in the direction of the insert axis C. 16, an outer peripheral surface 17 facing outward in the insert radial direction, a mounting hole 18 formed through the cutting insert 3 in the insert axis C direction and positioned on the insert axis C, and the cutting insert 3 being an insert mounting A cutting edge 5 that forms a cross ridge line between one circular surface 15 facing the front in the tool rotation direction T and the outer peripheral surface 17 of the pair of circular surfaces 15 and 16 in a state of being mounted on the seat 4; have.
The cutting insert 3 of the present embodiment is a single-sided round piece having a cutting edge 5 that forms a cross ridge line between one circular surface 15 of the pair of circular surfaces 15 and 16 and the outer peripheral surface 17. Although it is an insert, it is not limited to this. That is, the cutting insert 3 has a cutting edge 5 that forms a cross ridge line between at least one of the pair of circular surfaces 15 and 16 (that is, one or both of the circular surfaces 15 and 16) and the outer peripheral surface 17. Therefore, it may be, for example, a double piece type (front and back inverted symmetrical shape) circular piece insert.

  In the present embodiment, since the mounting hole 18 is formed at the center of each of the pair of circular surfaces 15 and 16, specifically, the circular surfaces 15 and 16 have an annular surface shape. . That is, the “circular surface” in this specification includes an annular surface of a circular surface.

  In one circular surface 15, the portion located inside the insert radial direction of the cutting edge 5 is a rake surface. The rake face is adjacent to the inner side in the insert radial direction of the cutting edge 5 and has an annular surface extending along the insert circumferential direction.

Further, the portion other than the mounting hole 18 in the other circular surface 16 has a planar shape perpendicular to the insert axis C. The other circular surface 16 is a seating surface that contacts the mounting surface 4 a of the insert mounting seat 4.
Note that, unlike the single-sided type of the present embodiment, in the case of the double-sided type cutting insert 3, the cutting inserts 3 have the same shape as each other with the cutting insert 3 mounted on the insert mounting seat 4. Of the pair of circular surfaces, the circular surface facing the front in the tool rotation direction T is a scoop surface, the circular surface facing the rear in the tool rotation direction T and seated on the mounting surface 4a of the insert mounting seat 4 Is the seating surface.

  In this embodiment, the outer peripheral surface 17 is gradually increased inward in the insert radial direction from the cutting edge 5 formed on the outer peripheral edge of one circular surface 15 toward the other circular surface 16 along the insert axis C direction. The circumferential surface portion adjacent to the cutting edge 5 is a flank. Although not shown in particular, a portion of the outer peripheral surface 17 located on the other circular surface 16 side along the insert axis C direction of the flank face has a second inclination different from the flank face with respect to the insert axis C. A surface may be formed, or a stepped portion retreating inward in the insert radial direction from the flank may be formed over the entire circumference in the insert circumferential direction.

  Further, the outer peripheral surface 17 has a convex curved surface portion 17a in which a shape appearing in a cross section perpendicular to the insert axis C forms a curved shape, and a shape appearing in a cross section perpendicular to the insert axis C forms a straight line, and from the convex curved surface portion 17a. Also, a flat portion 17b that recedes inward in the insert radial direction is formed. The flat surface portion 17b of the outer peripheral surface 17 is formed so that a part of the convex curved surface portion 17a is cut out. Specifically, a portion of the convex curved surface portion 17a other than the flank is chamfered in a flat shape. It is formed to be. In the present embodiment, at least the relief surface of the outer peripheral surface 17 is formed by the convex curved surface portion 17a, and the flat surface portion 17b is on the other circular surface 16 side along the insert axis C direction with respect to the cutting edge 5. The outer peripheral surface 17 is formed at a portion other than the flank surface while being spaced apart.

Further, in the present embodiment, the convex curved surface portion 17a of the outer peripheral surface 17 is formed in a conical shape that gradually decreases in diameter along the direction of the insert axis C from one circular surface 15 toward the other circular surface 16 side. Thus, the circular surfaces 15 and 16 are continued. Further, the convex curved surface portion 17a has a circular (annular) cross section perpendicular to the insert axis C at one circular surface 15 side portion (a flank portion adjacent to the cutting edge 5) along the insert axis C direction. In the other circular surface 16 side portion along the direction of the insert axis C, the cross section is formed into an arc shape by being divided into the flat portion 17b.
The convex curved surface portion 17a constitutes a portion of the outer peripheral surface 17 of the cutting insert 3 other than the flat surface portion 17b and an inclined portion 17c described later.

A plurality of flat surface portions 17b of the outer peripheral surface 17 are formed on the outer peripheral surface 17 at intervals in the insert circumferential direction. In the illustrated example, four plane portions 17b are formed on the outer peripheral surface 17 at equal intervals in the insert circumferential direction, and are arranged 90 ° rotationally symmetric (four times symmetrical) about the insert axis C. . The flat surface portion 17b is gradually inclined toward the inner side in the insert radial direction along the direction of the other circular surface 16 along the insert axis C direction. Instead of the above, eight planar portions 17b are formed on the outer peripheral surface 17 at equal intervals in the insert circumferential direction, and are arranged with 45 ° rotational symmetry (8-fold symmetry) about the insert axis C. It may be. In other words, a plurality of the plane portions 17b are formed on the outer peripheral surface 17 at equal intervals in the insert circumferential direction, and are disposed rotationally symmetrical at a predetermined angle about the insert axis C.
In the side view of the cutting insert 3 shown in FIGS. 6B and 7B, the flat surface portion 17b has a rectangular shape.

9 to 12, the convex curved surface portion 17 a and the flat surface portion 17 b extend in parallel with each other in the cross-sectional view along the insert radial direction shown in FIGS. 9 to 12 (cross-sectional view perpendicular to the insert circumferential direction). The inclination angles are made equal to each other. In the sectional view, the convex curved surface portion 17a and the flat surface portion 17b may extend non-parallel to each other and may have different inclination angles with respect to the insert axis C.
Here, the signs D ₁ and D ₂ shown in FIG. 9 to FIG. 12 indicate the flat surface portion 17b with respect to the convex curved surface portion 17a along the direction orthogonal to the convex curved surface portion 17a and the flat surface portion 17b in the sectional view. Represents the retreating amount (specifically, the maximum value of the retreating amount changing along the insert circumferential direction).

  Moreover, as shown in FIG. 6B and FIG. 7B, the outer peripheral surface 17 has an inclined portion at a position adjacent to the one circular surface 15 side along the insert axis C direction of the flat surface portion 17b. 17c is formed. The inclined portion 17c gradually inclines toward the outer side in the insert radial direction from the flat portion 17b toward the one circular surface 15 along the insert axis C direction, and extends along the insert axis C direction of the inclined portion 17c. On the one circular surface 15 side, a portion (flank surface portion) of the convex curved surface portion 17a that is a flank surface is disposed.

The inclination angle of the inclined portion 17c with respect to the insert axis C is larger than the inclination angle of the flat portion 17b and the convex curved surface portion 17a with respect to the insert axis C, and is a cross-sectional view of the cutting insert 3 shown in FIGS. The inclined portion 17c and the flat surface portion 17b, and the inclined portion 17c and the flank portion of the convex curved surface portion 17a are continuously connected so as to form an obtuse angle therebetween.
In the side view of the cutting insert 3 shown in FIGS. 6B and 7B, the inclined portion 17c has a half-moon shape.

And the cutting insert 3 comprised in this way is the retraction amount which the plane part 17b retreats with respect to the convex-curved-surface part 17a between multiple types of cutting insert 3A, 3B, as FIG. 9-12 shows. D ₁ and D ₂ are set differently.
In the present embodiment, as a plurality of types of cutting inserts 3 provided in the cutting edge replaceable cutting tool set 1, a first cutting insert excellent in outer diameter accuracy in which at least a flank portion of the convex curved surface portion 17 a is a polished surface. 3A and an inexpensive second cutting insert 3B in which the flank portion of the convex curved surface portion 17a is left as a sintered skin (no polished surface).

Specifically, as the first cutting insert 3A, there is an ISO class H-class insert or the like. In the first cutting insert 3A, the support wall surfaces 7a and 7b of the insert mounting seat 4 with respect to the first support portion 11 are used. The insert inscribed circle tolerance of the outer peripheral surface 17 (flank) is, for example, within a range of ± 0.013 mm. As the first cutting insert 3A, an ISO class G insert or the like in which at least the flank portion of the convex curved surface portion 17a is a polished surface may be used. In this case, the insert inscribed circle tolerance is used. Is, for example, within a range of ± 0.025 mm.
Moreover, as the 2nd cutting insert 3B, the M class insert etc. of ISO classification | category etc. are mentioned, In this 2nd cutting insert 3B, the outer peripheral surface with respect to the 1st support part 11 of the support wall surfaces 7a and 7b of the insert mounting seat 4 The insert inscribed circle tolerance of 17 (flank) is within a range of ± 0.08 mm, for example.

9 and 11, in the first cutting insert 3A, the retraction amount D1 by which the flat portion 17b is retreated with respect to the convex curved surface portion 17a is the _first amount in the insert mounting seat 4. The amount of protrusion H is such that the second support portion 12 protrudes from the support portion 11. Thus, when the first cutting insert 3A is mounted on the insert mounting seat 4, the convex curved surface portion 17a (the flank portion thereof) of the first cutting insert 3A is brought into contact with the first support portion 11. On the other hand, the plane portion 17 b is separated from the second support portion 12.

Further, as shown in FIGS. 10 and 12, in the second cutting insert 3B, the retracted amount D ₂ of planar portion 17b is retracted with respect to the convex curved portion 17a, the insert mounting seat 4, the first It is made smaller than the protrusion amount H by which the 2nd support part 12 is made to protrude with respect to the support part 11. FIG. Accordingly, when the second cutting insert 3B is mounted on the insert mounting seat 4, the flat surface portion 17b of the second cutting insert 3B is brought into contact with the second support portion 12, while the convex curved surface portion 17a ( The flank portion) is separated from the first support portion 11.

Further, the attachment hole 18 extends on the insert axis C, and both ends thereof open to the pair of circular surfaces 15 and 16. In the mounting hole 18, the end on the one circular surface 15 side along the insert axis C direction has a larger diameter than the portion other than the end, and in the illustrated example, a clamp screw is attached to this end. 25 screw heads are accommodated. The inner diameter of the mounting hole 18 other than the end on the one circular surface 15 side is smaller than the screw head of the clamp screw 25.
On the outer peripheral surface of the screw shaft portion of the clamp screw 25, a male screw portion subjected to male screw processing is formed, and the male screw portion is screwed to the female screw portion of the screw hole 4c.

  Next, a method of attaching the cutting insert 3 to the insert mounting seat 4 of the tool body 2 in the cutting edge replaceable cutting tool set 1 of the present embodiment (a cutting insert mounting method) will be described. The description of the same configuration as that described above is omitted.

In the mounting method of the cutting insert according to the present embodiment, the convex surface portion 17a and the flat surface portion 17b are formed on the outer peripheral surface 17 of the cutting insert 3, and the retraction amount D by which the flat surface portion 17b moves backward with respect to the convex curved surface portion 17a. the _{1, D 2,} a plurality of types of cutting inserts 3A, previously made different from each other in 3B together.

  On the other hand, the insert mounting seat 4 of the tool body 2 is formed with support wall surfaces 7a and 7b that come into contact with the outer peripheral surface 17 of the cutting insert 3, and the support wall surfaces 7a and 7b are arranged to face the convex curved surface portion 17a. In addition, the first support portion 11 formed in a concave curved surface shape corresponding to the shape of the convex curved portion 17a and the flat portion corresponding to the shape of the flat portion 17b are disposed opposite to the flat portion 17b. And a second support portion 12 that protrudes toward the cutting insert 3 attached to the insert mounting seat 4 from the first support portion 11.

Then, among the plurality of types of cutting inserts 3 </ b> A and 3 </ b> B, as shown in FIGS. 9 and 11, the retraction amount D ₁ is the protrusion amount H from which the second support portion 12 protrudes with respect to the first support portion 11. When the larger first cutting insert 3A is attached to the insert mounting seat 4, the flat surface portion 17b is the second portion while the convex curved surface portion 17a of the first cutting insert 3A is brought into contact with the first support portion 11. The support part 12 is separated.
Further, as shown in FIGS. 10 and 12, when the retraction amount D ₂ is mounted a small second cutting insert 3B than the amount of protrusion H in the insert mounting seat 4, the second cutting insert The convex curved surface portion 17 a is separated from the first support portion 11 while the 3B flat surface portion 17 b is brought into contact with the second support portion 12.

As described above, the cutting edge replaceable cutting tool set 1 of this embodiment can be used with a plurality of types of cutting inserts 3 attached to one tool body 2.
Specifically, among a plurality of types of cutting inserts 3, when attached to the insert mounting seat 4 by selecting the first cutting insert 3A the retraction amount D ₁ is large, the outer periphery of the first cutting insert 3A The convex curved surface portion 17a (the flank portion thereof) on the surface 17 is brought into contact with the concave curved first support portion 11 on the support wall surfaces 7a and 7b of the insert mounting seat 4, while the outer periphery of the first cutting insert 3A. The flat surface portion 17b on the surface 17 is disposed away from the flat second support portion 12 on the support wall surfaces 7a and 7b of the insert mounting seat 4.
Further, among a plurality of types of cutting inserts 3, when attached to the insert mounting seat 4 by selecting the second cutting insert 3B the retraction amount D ₂ is small, the outer peripheral surface of the second cutting insert 3B 17 The flat surface portion 17b of the insert mounting seat 4 is brought into contact with the flat second support portion 12 of the support wall surface 7a, 7b, while the convex curved surface portion 17a (the relief of the outer peripheral surface 17 of the second cutting insert 3B). The surface portion) is disposed apart from the concave curved first support portion 11 on the support wall surfaces 7a and 7b of the insert mounting seat 4.

Thus, depending on the type of the cutting insert 3, the convex curved surface portion 17a of the outer peripheral surface 17 of the cutting insert 3 is brought into contact with the support wall surfaces 7a and 7b (first support portion 11) of the insert mounting seat 4, or It is possible to select whether the flat surface portion 17b is brought into contact with the support wall surfaces 7a and 7b (second support portion 12). Thereby, the following effects can be obtained.
That is, among the plurality of types of cutting inserts 3, as described in the present embodiment, for example, the ISO class H class in which the outer diameter accuracy of the convex curved surface portion 17a (flank) of the outer peripheral surface 17 is ensured by polishing or the like. When an insert, a G-class insert or the like is used as the first cutting insert 3A and the first cutting insert 3A is mounted on the insert mounting seat 4, the cutting insert is inserted into the support wall surfaces 7a and 7b of the insert mounting seat 4. The convex curved surface portion 17a is brought into contact with the outer peripheral surface 17 of 3A. That is, since the outer diameter accuracy of the first cutting insert 3A is ensured, the convex curved surface portion 17a is supported by supporting the convex curved surface portion 17a against the support wall surfaces 7a and 7b (first support portion 11). The wall surfaces 7a and 7b come into contact with each other in a wide range without hitting a point, and a contact area is ensured. Thereby, the cutting insert 3A can be stably mounted on the insert mounting seat 4, and the cutting edge 5 can be positioned with high accuracy, and high-quality cutting can be stably performed.

  On the other hand, among the plurality of types of cutting inserts 3, as described in the present embodiment, for example, the convex curved surface portion 17 a (flank) of the outer peripheral surface 17 is a sintered skin (without polishing), When using a class M insert of ISO classification whose outer diameter accuracy is inferior to that of a class G insert as the second cutting insert 3B and mounting the second cutting insert 3B to the insert mounting seat 4, the insert mounting seat 4 Of the outer peripheral surface 17 of the cutting insert 3B, the flat surface portion 17b is brought into contact with the support wall surfaces 7a and 7b. That is, although the second cutting insert 3B has a low outer diameter accuracy, the flat portion 17b is brought into contact with the support wall surfaces 7a and 7b (second support portion 12), so that the flat portion 17b and the support wall surfaces 7a and 7b The contact area is ensured by contacting a wide range without hitting. Thereby, the cutting insert 3B can be stably mounted on the insert mounting seat 4, and the cutting can be stably performed with the intended processing accuracy.

Specifically, as shown in FIG. 13, when a cutting insert 3 having a low outer diameter accuracy such as an M-class insert is attached to the insert mounting seat 4 in the related art, a conical portion on the outer peripheral surface 17 of the cutting insert 3. Is brought into contact with the concave conical portions of the support wall surfaces 7a and 7b of the insert mounting seat 4. Therefore, when the outer peripheral surface 17 is formed largely by the outer diameter tolerance allowed at the time of manufacturing the cutting insert 3 (in the case of a virtual circle indicated by a two-dot chain line in FIG. 13), the outer peripheral surface 17 and the support wall surface 7a. , 7b due to the difference in curvature from the outer peripheral surface 17 with respect to the support wall surfaces 7a, 7b at a point indicated by the symbol X, and when the outer peripheral surface 17 is formed small (not shown), The outer peripheral surface 17 was spotted at a position indicated by a symbol Y with respect to the support wall surfaces 7a and 7b. It is difficult to maintain the accuracy of the cutting process because the X part and the Y part of the support wall surfaces 7a and 7b of the insert mounting seat 4 are worn or deformed due to such hits.
On the other hand, according to this embodiment, the location where the cutting insert 3 is brought into contact with the insert mounting seat 4 can be changed according to the difference in the outer diameter accuracy of the cutting insert 3. Thus, the outer peripheral surface 17 of the cutting insert 3 can be stably brought into surface contact, and the above-described point hitting phenomenon can be effectively suppressed. Therefore, the cutting accuracy can be stably maintained at a high quality.

  In addition, “predetermined cutting inserts 3 selected from a plurality of types of disc-shaped cutting inserts 3 are detachably mounted on the insert mounting seat 4” described in the present embodiment. Assumes that one of the above-described first and second cutting inserts 3A and 3B is mounted on the insert mounting seat 4. However, the present invention is not limited to this. For example, when a plurality of insert mounting seats 4 are provided as in this embodiment, one of these insert mounting seats 4 has high cutting edge position accuracy. A class H insert may be mounted as a finishing blade, and a rough class M insert may be mounted on other insert mounting seats.

  From the above, according to the cutting edge set type cutting tool set 1, the tool main body 2, and the cutting insert mounting method of the present embodiment, the outer circumference of the cutting insert 3 depends on the outer diameter accuracy of the disc-shaped cutting insert 3. The positions of the support wall surfaces 7a and 7b of the insert mounting seat 4 with which the surface 17 abuts can be selected, whereby high-precision cutting can be stably performed while using a plurality of types of cutting inserts 3. .

Moreover, in this embodiment, since it decided that at least the part (flank part) contact | abutted to the 1st support part 11 among the convex curve parts 17a of 3 A of 1st cutting inserts is a grinding | polishing processing surface, The effect of.
That is, in this case, the outer diameter accuracy of the convex curved surface portion 17a (flank surface portion) on the outer peripheral surface 17 of the first cutting insert 3A can be reliably increased, and the above-described effects can be obtained more remarkably.
In the present embodiment, at least the flank portion of the convex curved surface portion 17a of the first cutting insert 3A is a polished surface. However, the present invention is not limited to this, and the convex curved surface portion 17a Of these, at least the portion that is in contact with the first support portion 11 is a polished surface, so that the above-described effects can be obtained. Further, when the outer diameter accuracy of the convex curved surface portion 17a of the first cutting insert 3A can be ensured within a predetermined tolerance range without performing the polishing process, the polishing process may not be performed.

Moreover, in this embodiment, since the plane part 17b in the outer peripheral surface 17 of the cutting insert 3 is formed so that a part of convex-curved surface part 17a may be notched, there exists the following effect.
That is, in this case, the shape of the cutting insert 3 is simplified without being complicated, and the convex curved surface portion 17 a and the flat surface portion 17 b can be easily formed on the outer peripheral surface 17 of the cutting insert 3. Moreover, since the outer peripheral wall thickness of the cutting insert 3 can be sufficiently secured, it is easy to ensure the insert rigidity.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, the first cutting insert 3A and the second cutting insert 3B are used as the plurality of types of cutting inserts 3 included in the cutting edge replaceable cutting tool set 1, but these cutting inserts are further described. Other cutting inserts 3 (third, fourth, fifth... Cutting inserts 3) different in outer diameter accuracy from 3A and 3B may be provided.
In this case, according to the outer diameter accuracy of the other cutting insert 3, the outer peripheral surface 17 of the cutting insert 3 is not allowed to hit the support wall surfaces 7a and 7b of the insert mounting seat 4 (the convex curved surface portion 17a or By bringing them into contact with each other at the flat portion 17b), the same effects as those of the above-described embodiment can be obtained.

  Moreover, in the above-mentioned embodiment, although the plane part 17b in the outer peripheral surface 17 of the cutting insert 3 was formed so that a part of convex-curved surface part 17a might be notched, it is not limited to this. That is, for example, the convex curved surface portion 17a is formed only in the flank portion adjacent to the cutting edge 5 in the outer peripheral surface 17, and the other circle along the insert axis C direction in the outer peripheral surface 17 rather than the convex curved surface portion 17a. A flat surface portion 17b may be formed on the outer surface of the polygonal cross section located on the shape surface 16 side.

In the above-described embodiment, the single-sided type cutting insert 3 and the insert mounting seat 4 to which the single-sided type cutting insert 3 is mounted have been described. However, as described above, the present invention can also be applied to the double-sided type cutting insert 3. Specific examples include the following configurations.
That is, as the double-sided type cutting insert 3, for example, if it is described without considering the external dimensions, the cutting insert 3 shown in FIGS. A double-sided insert or the like having a shape in which another cutting insert 3 (not shown) obtained by inverting 3 in plane symmetry can be used.

In the above-described embodiment, the convex curved surface portion 17a and the flat surface portion 17b extend with an inclination with respect to the insert axis C in the cross-sectional views shown in FIGS. Although the first and second support portions 11 and 12 are described with the configuration in which the first and second support portions 11 and 12 are inclined and extended as examples, the present invention is not limited to this.
That is, in the cross-sectional view, either or both of the convex curved surface portion 17a and the flat surface portion 17b extend in parallel with the insert axis C, and correspondingly, the first axis with respect to the central axis of the screw hole 4c. Any one or both of the second support portions 11 and 12 may extend in parallel.
In the case where the cutting insert 3 is the above-described double-sided insert, in the cross-sectional view, either the convex curved surface portion 17a or the flat surface portion 17b is inclined and extends with respect to the insert axis C. The cutting insert 3 is manufactured by sintering a pair of divided bodies (compacts) facing each other in the direction of the insert axis C in a state where they are bonded to each other so as to be in plane symmetry (inverted symmetry). preferable.

  In addition, in the range which does not deviate from the meaning of this invention, you may combine each structure (component) demonstrated by the above-mentioned embodiment, a modified example, a note, etc., addition of a structure, omission, substitution, others It can be changed. Further, the present invention is not limited by the above-described embodiments, and is limited only by the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Cutting edge exchange type cutting tool set 2 Tool main body 3 Cutting insert 3A 1st cutting insert 3B 2nd cutting insert 4 Insert mounting seat 5 Cutting edge 7a, 7b Wall surface (support wall surface)
11 1st support part 12 2nd support part 15 One circular surface (rake face)
16 The other circular surface (sitting surface)
17 Outer peripheral surface (flank)
17a Convex curved surface portion 17b Planar portion C Insert axis D ₁ , D ₂ Retraction amount H Projection amount O Tool axis

Claims (5)

A cutting edge exchange type in which a predetermined cutting insert selected from a plurality of types of disc-shaped cutting inserts is detachably mounted on an insert mounting seat formed on the outer periphery of the tip of the tool body that rotates about the tool axis. A cutting tool set,
The cutting insert is
A pair of circular surfaces facing the insert axial direction of the cutting insert;
An outer peripheral surface facing the outside in the insert radial direction perpendicular to the insert axis;
Having at least one of the pair of circular surfaces and a cutting edge forming a cross ridge line with the outer peripheral surface;
On the outer peripheral surface,
A convex curved surface portion in which a shape appearing in a cross section perpendicular to the insert axis forms a curved shape;
A shape that appears in a cross section perpendicular to the insert axis is a straight line, and a flat surface portion that recedes inward in the insert radial direction from the convex curved surface portion is formed,
The amount of retreat in which the flat surface portion retreats with respect to the convex curved surface portion is different from each other among a plurality of types of the cutting inserts,
The insert mounting seat is formed with a support wall surface that comes into contact with the outer peripheral surface of the cutting insert,
The supporting wall surface is
A first support portion which is disposed opposite to the convex curved surface portion and is formed in a concave curved surface shape corresponding to the shape of the convex curved surface portion;
A second surface that is disposed opposite to the flat surface portion and that is formed in a flat shape corresponding to the shape of the flat surface portion and protrudes toward the cutting insert mounted on the insert mounting seat from the first support portion. A support portion;
For multiple types of cutting inserts,
A first cutting insert in which the retraction amount is larger than a protrusion amount by which the second support portion protrudes with respect to the first support portion;
The blade tip exchangeable cutting tool set, comprising: a second cutting insert in which the retraction amount is smaller than the protrusion amount. In the cutting edge set type cutting tool set according to claim 1,
The cutting edge set replaceable cutting tool set, wherein the convex curved surface portion of the first cutting insert is a polished surface. In the cutting edge replaceable cutting tool set according to claim 1 or 2,
The cutting edge set replaceable cutting tool set, wherein the flat surface portion of the outer peripheral surface of the cutting insert is formed such that a part of the convex curved surface portion is cut out.   A tool body used in the cutting edge replaceable cutting tool set according to any one of claims 1 to 3. A tool-blade exchange type comprising: a tool body that rotates about a tool axis; and a disc-shaped cutting insert that is selected from a plurality of types and mounted on an insert mounting seat formed on the outer periphery of the tip of the tool body. A cutting insert mounting method for mounting the cutting insert on the insert mounting seat of a cutting tool set,
The cutting insert is
A pair of circular surfaces facing the insert axial direction of the cutting insert;
An outer peripheral surface facing the outside in the insert radial direction perpendicular to the insert axis;
Having at least one of the pair of circular surfaces and a cutting edge forming a cross ridge line with the outer peripheral surface;
On the outer peripheral surface,
A convex curved surface portion in which a shape appearing in a cross section perpendicular to the insert axis forms a curved shape;
The shape appearing in the cross section perpendicular to the insert axis is a straight line, and forms a flat part that recedes inwardly in the insert radial direction from the convex curved part,
The amount of retreat in which the flat surface portion retreats with respect to the convex curved surface portion is made different between the plurality of types of cutting inserts,
Forming a support wall surface in contact with the outer peripheral surface of the cutting insert on the insert mounting seat;
The supporting wall surface includes
A first support portion that is disposed opposite to the convex curved surface portion and is formed in a concave curved surface shape corresponding to the shape of the convex curved surface portion;
A second surface that is disposed opposite to the flat surface portion and that is formed in a flat shape corresponding to the shape of the flat surface portion and protrudes toward the cutting insert mounted on the insert mounting seat from the first support portion. A support portion;
Among the multiple types of cutting inserts,
When the first cutting insert is mounted on the insert mounting seat, the retraction amount is larger than the protrusion amount that the second support portion protrudes with respect to the first support portion. Bringing the convex curved surface portion into contact with the first support portion;
When mounting the second cutting insert whose retraction amount is smaller than the protrusion amount on the insert mounting seat, the flat portion of the second cutting insert is brought into contact with the second support portion. The mounting method of the cutting insert which is characterized.

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