JP2022083010A - Cutting edge replacement type cutting tool - Google Patents

Abstract

To precisely align a cutting insert, to stably clamp it, to suppress the positional deviation of the cutting insert to a tip end side in an axial direction at clamping, and to improve versatility.SOLUTION: A holder 3 has a holder cylinder portion 32 that has a male screw portion 32a on an outer peripheral surface, and a regulating portion 34 that regulates rotations about a center axis C and movement toward a rear end side in an axial direction of the cutting insert 2. The cutting insert 2 has a columnar portion 24, and a locking portion 25 contacted with the regulating portion 34. A chuck mechanism 4 has an installation cylinder portion 41 that has a female screw portion 41a on an inner peripheral surface, and a collet portion 42 capable of changing a diameter. A holder cylinder portion 32 has an inner peripheral tapered surface 32b. The collet portion 42 has an outer peripheral tapered surface 42b slidably contacted with the inner peripheral tapered surface 32b. The installation cylinder portion 41 has a forcing portion 41b that can force the collet portion 42 to the rear end side in the axial direction when the screwing amount of the male screw portion 32a and the female screw portion 41a is increased.SELECTED DRAWING: Figure 5

Description

The present invention relates to a cutting tool with a replaceable cutting edge.

As a conventional cutting tool with a replaceable cutting edge, for example, those described in the following Patent Documents 1 to 4 are known. The cutting tool with replaceable cutting edge has a shaft-shaped cutting insert extending axially around the central axis and an insertion hole into which the cutting insert is inserted, and a columnar holder extending axially and inserted into the insertion hole. It is provided with a fixing mechanism for detachably fixing the cutting insert to the holder.

Specifically, in Patent Document 1, the tip plane of the screw member screwed to the holder in a state where the inclined surface of the rear end of the insert is in contact with the positioning member provided in the insertion hole of the holder is the upper surface of the insert. The insert is fixed to the holder by abutting on the second cut surface of the above.

Further, in Patent Document 2, the cutting insert is inserted through the retaining ring by screwing the screw nut into the screw sleeve with the inclined surface of the rear end of the cutting insert in contact with the lateral stop in the insertion hole of the holder. It is fixed to the holder.

Further, in Patent Document 3, in a state where the rear end surface of the throw-away insert (cutting insert) is in contact with the fixing member in the insertion hole of the holder, a bolt is screwed into the holder so as to connect between the first slit grooves of the holder. By being combined, the wall surface of the hole is pressed against the holder restraining portion of the chip, and the side surface of the chip is restrained by the holder.

Further, in Patent Document 4, the clamp chuck is reduced in diameter and cut by tightening the union nut to the clamp chuck using a spanner in a state where the chamfered region of the cutting insert abuts on the positioning pin in the insertion hole of the holder. Clamp the insert.

Japanese Unexamined Patent Publication No. 2013-71214 German Patented Invention No. 19831743 Japanese Patent No. 3690675 U.S. Pat. No. 9993880

The conventional cutting tool with a replaceable cutting edge has the following problems.
In Patent Document 1, the insert is pressed against a part of the inner peripheral surface of the insertion hole of the holder by pressing the upper surface of the insert with a screw member. The core (central axis) may shift or the durability may decrease. Further, when tightening the screw member, the insert may be displaced toward the tip side in the axial direction with respect to the holder.

In Patent Document 2, the cutting insert cannot be stably fixed to the insertion hole of the holder in the radial direction, and the core of the holder and the cutting insert may be misaligned. In addition, the cutting insert may be displaced toward the tip side in the axial direction with respect to the holder.

In Patent Document 3, since the side surface of the throw-away tip is sandwiched and clamped by the wall surface of the hole, the clamping force and rigidity of the tip cannot be secured in the radial direction different from the sandwiching direction. In addition, the throw-away tip may be displaced toward the tip side in the axial direction with respect to the holder.

In Patent Document 4, the cutting insert may be displaced toward the tip end side in the axial direction with respect to the holder.
Further, in Patent Documents 1 to 4, only one type of cutting insert diameter can be used for one type of holder, and the versatility is low.

According to the present invention, the cutting insert can be accurately aligned with the holder, the cutting insert can be stably clamped, the cutting insert can be prevented from being displaced toward the tip side in the axial direction at the time of clamping, and one type of cutting insert can be suppressed. One of the purposes of the present invention is to provide a cutting tool with a replaceable cutting edge, which can use a plurality of types of cutting inserts having different diameters for a holder and enhance versatility.

One aspect of the cutting tool with a replaceable cutting edge of the present invention has a shaft-shaped cutting insert extending in the axial direction about the central axis and an insertion hole into which the cutting insert is inserted, and has a columnar shape extending in the axial direction. A holder and a chuck mechanism for detachably fixing the cutting insert inserted into the insertion hole to the holder are provided, and the holder is located at the axial tip portion of the holder and the insertion hole is provided. The holder cylinder, which is arranged coaxially with and has a male screw portion on the outer peripheral surface, comes into contact with the cutting insert inside the insertion hole, and the rotation of the cutting insert around the central axis and the rear end side in the axial direction. The cutting insert has a restricting portion that restricts movement toward the holder, a cylindrical portion that is at least partially arranged inside the holder cylinder portion, a locking portion that contacts the restricting portion, and the above-mentioned The chuck mechanism has a mounting cylinder portion having a female screw portion screwed to the male screw portion on the inner peripheral surface, and a mounting cylinder portion having a cutting edge protruding toward the tip end side in the axial direction from the holder cylinder portion. A tubular collet that is separate from the mounting cylinder and is arranged between the mounting cylinder, the holder cylinder, and the cylinder in the radial direction orthogonal to the central axis, and has a variable diameter. The holder cylinder portion has an inner peripheral tapered surface whose inner diameter increases toward the tip side in the axial direction, and the collet portion has an outer diameter toward the tip side in the axial direction. Has an outer peripheral tapered surface that is slidably in contact with the inner peripheral tapered surface, and the mounting cylinder portion is said to have a screwing amount between the male screw portion and the female screw portion. It has a pushing portion that can push the collet portion toward the rear end side in the axial direction.

In the cutting tool with a replaceable cutting edge of the present invention, a cutting insert is inserted inside the collet portion forming a cylindrical shape in the radial direction, and the locking portion of the cutting insert is brought into contact with the regulating portion in the insertion hole of the holder. By screwing the mounting cylinder portion to the holder cylinder portion, the cutting insert is clamped while being aligned with the holder and fixed to the holder.

Specifically, when the locking portion of the cutting insert is brought into contact with the restricting portion of the holder, the rotation of the cutting insert with respect to the center axis around the central axis and the movement toward the rear end side in the axial direction are restricted. That is, the cutting insert is phase-aligned in the circumferential direction and positioned in the axial direction (toward the rear end side).
From this state, when the mounting cylinder portion is rotated around the central axis to increase the screwing amount between the female screw portion and the male screw portion, the pushing portion of the mounting cylinder portion moves the collet portion to the rear end side in the axial direction. Push into. As a result, the inner peripheral surface of the collet portion is reduced in diameter while the outer peripheral tapered surface of the collet portion and the inner peripheral tapered surface of the holder cylinder portion are in sliding contact with each other, and the inner peripheral surface of the collet portion presses the cylindrical portion of the cutting insert from the outside in the radial direction. do. That is, the collet portion uniformly clamps the cutting insert in the circumferential direction while applying a pulling force toward the rear end side in the axial direction to the cutting insert.

According to the present invention, the insertion hole and the holder cylinder portion are coaxial with each other, and the cutting insert is clamped by the collet portion reduced in diameter by the sliding contact with the holder cylinder portion. On the other hand, the cutting insert can be centered coaxially with high accuracy.

Further, it is not necessary to provide the cylindrical portion of the cutting insert with a D-cut flat surface portion for contacting the tip of the screw member as in the conventional case, and according to the present invention, the rigidity of the cutting insert is increased. Further, a large contact area between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the collet portion can be secured, that is, the collet portion can hold the cutting insert over the entire circumference around the central axis, so that the cutting insert can be stably clamped. According to the present invention, the tool rigidity is ensured evenly in the circumferential direction.

Further, when the collet portion clamps the cutting insert, the collet portion applies a pulling force toward the other side in the axial direction to the cutting insert, so that the locking portion of the cutting insert is abutted against the restricting portion of the holder. The condition is maintained in good condition. Therefore, it is possible to prevent the cutting insert from being displaced toward the tip end side in the axial direction during clamping. That is, in the present invention, the axial positioning accuracy of the cutting insert is stably ensured before and after the clamp.
In addition, from the state where the locking part of the cutting insert and the restricting part of the holder are closely arranged with a gap between them, the mounting cylinder part is screwed to the holder cylinder part and the pulling force of the collet part is used. It is also possible to move the cutting insert to the rear end side in the axial direction so that the locking portion and the restricting portion come into contact with each other. In this case, the operability at the time of insert clamping is further improved while the positioning accuracy of the cutting insert is ensured.

Also, by replacing the collet part, which is separate from the mounting cylinder part, with another collet part with a different inner diameter, it is possible to use multiple types of cutting inserts with different diameters for one type of holder. can. Therefore, the cutting tool with a replaceable cutting edge of the present invention can meet various cutting conditions and the like, and its versatility is enhanced.

Further, in the present invention, the cutting insert can be clamped at the tip of the tool by, for example, rotating the mounting cylinder from the front of the holder, and the operability is good. Further, since the cutting insert is firmly clamped at the tip of the tool, the rigidity of the tool is increased, chatter vibration during cutting can be suppressed, and the machining accuracy is stably improved.

In the cutting tool with a replaceable cutting edge, the collet portion has a plurality of slits arranged at intervals in the circumferential direction around the central axis, and the collet is decreased or increased in width. It is preferable that the diameter of the portion changes.

In this case, the collet portion can be reduced in diameter or expanded in diameter with a simple configuration. The collet portion allows the cutting insert to be clamped evenly and stably in the circumferential direction.

In the cutting tool with a replaceable cutting edge, the collet portion is arranged on the outer peripheral surface of the collet portion, and has a tapered surface-shaped receiving portion whose diameter increases toward the rear end side in the axial direction. , It is a tapered surface that is arranged on the inner peripheral surface of the mounting cylinder and expands in diameter toward the rear end side in the axial direction, and the receiving portion can be pushed toward the rear end side in the axial direction. preferable.

In this case, even if the collet portion is reduced in diameter by being pushed into the holder cylinder portion, the contact state between the tapered surface-shaped receiving portion and the tapered surface-shaped pushing portion is maintained satisfactorily. Therefore, the receiving portion can be stably pushed toward the rear end side in the axial direction by the pushing portion, and the cutting insert can be stably clamped.

In the cutting tool with a replaceable cutting edge, it is preferable that a plurality of locking portions are provided on the cutting insert at intervals in the axial direction.

In this case, the amount of protrusion of the cutting edge of the cutting insert can be appropriately selected by appropriately selecting one locking portion to be brought into contact with the restricting portion of the holder from the plurality of locking portions. That is, it is easy to greatly change the amount of protrusion of the cutting edge by using one cutting insert.

In the cutting tool with a replaceable cutting edge, the holder has a female screw hole that opens in the outer peripheral surface of the holder and the insertion hole, and is located on the tip side in the axial direction toward the inside in the radial direction. The restricting portion may be a male screw member that is screwed into the female screw hole and protrudes into the insertion hole.

In this case, by adjusting the screwing amount of the male screw member into the female screw hole, the axial position where the locking portion of the cutting insert and the male screw member (regulatory portion) come into contact can be finely adjusted. This makes it possible to finely adjust the axial position of the cutting edge of the cutting insert, that is, the amount of protrusion.

In the cutting tool with a replaceable cutting edge, the holder has a pin hole that opens on the outer peripheral surface of the holder and the insertion hole, and the restricting portion fits into the pin hole and passes through the inside of the insertion hole. It may be a pin member.

In this case, since the pin member (regulating portion) is suppressed from moving in the axial direction with respect to the holder, the accuracy of the axial position of the cutting edge of the cutting insert, that is, the protrusion amount is stably ensured.

In the cutting tool with a replaceable cutting edge, it is preferable that the cutting insert has an abutting portion that contacts the pin member from the rear end side in the axial direction.

In this case, the contact between the locking portion and the pin member (regulatory portion) and the contact between the contact portion and the pin member restrict the movement of the cutting insert to the rear end side and the tip side in the axial direction. For example, even when a force for pulling out the cutting insert from the insertion hole of the holder toward the tip end side in the axial direction acts during cutting, the cutting insert is suppressed from coming out.

In the cutting tool with a replaceable cutting edge, it is preferable that the chuck mechanism has a bearing interposed between the pushing portion and the collet portion.

In this case, even if the mounting cylinder portion is rotated around the central axis when the cutting insert is clamped, the bearing is provided between the pushing portion and the collet portion, so that the collet portion is suppressed from rotating. That is, since rotational behavior is suppressed in the collet portion, only the pressing force (clamping force) from the outside in the radial direction and the pulling force toward the rear end side in the axial direction are applied to the cutting insert via the collet portion. be able to. Therefore, the phase alignment in the circumferential direction and the positioning in the axial direction of the cutting insert can be accurately performed, and the load on each positioning element (regulatory portion, locking portion, etc.) is reduced.

In the blade tip exchange type cutting tool, the cutting insert has a shaft-shaped insert shank extending in the axial direction and a blade portion arranged at the tip portion of the insert shank in the axial direction. The cutting edge may be arranged in the insert shank, and the columnar portion and the locking portion may be arranged in the insert shank.

In this case, for example, the insert shank can be made of a material having higher toughness and lower cost than the blade portion. While reducing the tool cost, it is possible to further suppress defects such as locking portions.

According to the cutting tool with a replaceable cutting edge according to one aspect of the present invention, the cutting insert can be accurately aligned with the holder, the cutting insert can be stably clamped, and the cutting insert is positioned on the tip side in the axial direction at the time of clamping. It is possible to suppress the deviation, and it is possible to use a plurality of types of cutting inserts having different diameters for one type of holder, and the versatility is enhanced.

FIG. 1 is a perspective view showing a cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 2 is a side view showing a cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 3 is a top view showing a cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 4 is a front view showing a cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 5 is a cross-sectional view showing a cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 6 is a cross-sectional view showing a first modification of the cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 7 is a cross-sectional view showing a second modification of the cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 8 is a cross-sectional view showing a third modification of the cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 9 is a cross-sectional view showing a fourth modification of the cutting tool with a replaceable cutting edge according to the present embodiment. FIG. 10 is a top view showing a part of a cutting tool with a replaceable cutting edge according to a fifth modification of the present embodiment.

The cutting tool 1A having a replaceable cutting edge according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 5, the blade edge exchange type cutting tool 1A of the present embodiment is a blade edge exchange type cutting tool used for turning, and is attached to and detached from a tool post of a machine tool M such as an NC lathe. Can be installed. Specifically, this cutting tool 1A with a replaceable cutting edge is used for finishing the inner peripheral surface of a pilot hole provided in advance in a work material (not shown).

As shown in FIG. 5, the cutting tool 1A having a replaceable cutting edge has a shaft-shaped cutting insert 2 centered on a central axis C, a columnar holder 3 having an insertion hole 31 into which the cutting insert 2 is inserted, and an insertion hole. A chuck mechanism 4 for detachably fixing the cutting insert 2 inserted in 31 to the holder 3 is provided.
The cutting insert 2, the holder 3, and the chuck mechanism 4 are arranged coaxially with each other with the central axis C as a common axis.

[Definition of direction]
In the present embodiment, the direction in which the central axis C extends is referred to as an axial direction. The cutting insert 2 has a portion protruding from the holder 3 in the axial direction. In the present embodiment, the direction in which the cutting insert 2 protrudes from the holder 3 in the axial direction is referred to as the tip end side, and the direction opposite to this is referred to as the rear end side.
Further, the direction orthogonal to the central axis C is called the radial direction. Of the radial directions, the direction closer to the central axis C is called the radial inner side, and the direction away from the central axis C is called the radial outer side. The cutting insert 2 has a rake face 21 described later at the tip portion in the axial direction. In the present embodiment, among the radial directions, the direction in which the rake face 21 faces is referred to as an upper side, and the direction opposite to this is referred to as a lower side. It should be noted that the upper side and the lower side are simply names for explaining the relative positional relationship of each part, and the actual arrangement relationship or the like may be an arrangement relationship or the like other than the arrangement relationship or the like indicated by these names. ..
Further, the direction of orbiting around the central axis C is called the circumferential direction.

[Cutting insert]
The cutting insert 2 is made of, for example, cemented carbide, and in this embodiment, it is integrally formed of a single member. The cutting insert 2 extends axially. At least the tip of the cutting insert 2 projects from the holder 3 toward the tip. The cutting insert 2 has a rake face 21, a flank surface 22, a cutting edge 23, a cylindrical portion 24, and a locking portion 25.

As shown in FIGS. 1 to 4, the rake face 21, the flank surface 22, and the cutting edge 23 are arranged at the tip end portion of the cutting insert 2. The rake surface 21, the flank surface 22, and the cutting edge 23 project toward the tip end side in the axial direction from the holder cylinder portion 32, which will be described later, of the holder 3. The rake face 21, the flank surface 22, and the cutting edge 23 are located on the tip side of the holder 3 and the chuck mechanism 4 in the axial direction.

The rake face 21 is a flat surface facing upward in the radial direction. The flank 22 has a portion facing the tip side in the axial direction (front flank surface) and a portion facing outward in the radial direction (side flank surface). The cutting edge 23 is located at the ridgeline portion where the rake surface 21 and the flank surface 22 are connected. In the present embodiment, the cutting edge 23 is substantially V-shaped in the top view shown in FIG. The cutting edge 23 projects from the tip portion of the cutting insert 2 other than the cutting edge 23 to the tip end side in the axial direction and to the outside in the radial direction.

As shown in FIG. 5, the columnar portion 24 has a columnar shape centered on the central axis C and extends in the axial direction. The cylindrical portion 24 is arranged in an intermediate portion located between both ends in the axial direction of the cutting insert 2. Although not particularly shown, the cylindrical portion 24 has a circular cross section perpendicular to the central axis C. That is, the outer peripheral surface of the cylindrical portion 24 has a cylindrical surface shape centered on the central axis C. At least a part of the cylindrical portion 24 is arranged inside the holder cylinder portion 32 described later in the holder 3. Specifically, the cylindrical portion 24 is arranged over the inside of the insertion hole 31, the inside of the holder cylinder portion 32, and the inside of the chuck mechanism 4.

The locking portion 25 is arranged at the rear end portion of the cutting insert 2. In the present embodiment, the locking portion 25 has an inclined surface shape that is inclined with respect to the central axis C. In the illustrated example, the locking portion 25 is located upward toward the tip end side in the axial direction. The locking portion 25 has a planar shape extending in a direction intersecting the central axis C, and has a substantially elliptical shape in the present embodiment. The locking portion 25 is arranged over substantially the entire rear end surface of the cutting insert 2 and includes a portion located on the central axis C. The locking portion 25 comes into contact with the restricting portion 34 of the holder 3, which will be described later.

〔holder〕
The constituent members of the holder 3 are made of, for example, steel. The holder 3 extends in the axial direction about the central axis C. As shown in FIG. 5, with the cutting tool 1A having a replaceable cutting edge attached to the machine tool M, a portion other than the tip end portion of the holder 3 is embedded and arranged inside the machine tool M. The holder 3 has an insertion hole 31, a holder cylinder portion 32, a female screw hole 33, and a regulation portion 34.

The insertion hole 31 penetrates the holder 3 in the axial direction. The central axis of the insertion hole 31 is arranged coaxially with the central axis C of the holder 3. The tip portion 31a in the axial direction of the insertion hole 31 opens inside the holder cylinder portion 32. The rear end portion 31b in the axial direction of the insertion hole 31 opens to the rear end surface of the holder 3. The inner diameter of the intermediate portion 31c located between the tip portion 31a and the rear end portion 31b in the axial direction of the insertion hole 31 is larger than the inner diameter of the tip portion 31a and smaller than the inner diameter of the rear end portion 31b. Further, the axial length of the intermediate portion 31c is larger than the axial length of the front end portion 31a, and is larger than the axial length of the rear end portion 31b. In the present embodiment, the cutting insert 2 is inserted over the tip portion 31a of the insertion hole 31 and the tip end side portion of the intermediate portion 31c. The cylindrical portion 24 of the cutting insert 2 is slidably inserted (fitted) into the tip portion 31a.

The holder cylinder portion 32 is located at the tip portion of the holder 3 in the axial direction. The central axis of the holder cylinder portion 32 is arranged coaxially with the central axis C of the insertion hole 31. With the cutting tool 1A having a replaceable cutting edge attached to the machine tool M, the holder cylinder portion 32 is exposed to the outside without being embedded inside the machine tool M. In the present embodiment, the outer diameter of the portion of the holder cylinder portion 32 other than the rear end portion is smaller than the outer diameter of the rear end portion. The holder cylinder portion 32 has a male screw portion 32a and an inner peripheral tapered surface 32b.

The male screw portion 32a is provided on the outer peripheral surface of the holder cylinder portion 32. In the present embodiment, the male screw portion 32a is arranged in a portion of the holder cylinder portion 32 other than the rear end portion.
The inner peripheral tapered surface 32b is arranged on the inner peripheral surface of the holder cylinder portion 32. The inner peripheral tapered surface 32b has a tapered shape in which the inner diameter increases toward the tip side in the axial direction.

The female screw hole 33 opens in the outer peripheral surface of the holder 3 and the insertion hole 31, and is located on the tip end side in the axial direction toward the inside in the radial direction. The female screw hole 33 extends in a direction intersecting (inclining) the central axis C. The female screw hole 33 has a circular hole shape and has a female screw on the inner peripheral surface. In the present embodiment, the female screw hole 33 opens at an intermediate portion of the outer peripheral surface of the holder 3 located between both ends in the axial direction and at the intermediate portion 31c of the inner peripheral surface of the insertion hole 31.

The restricting portion 34 contacts the cutting insert 2 inside the insertion hole 31 and restricts the rotation of the cutting insert 2 around the central axis C (that is, the circumferential direction) and the movement toward the rear end side in the axial direction. In the present embodiment, the regulating portion 34 is a male screw member 34a that is screwed into the female screw hole 33 and protrudes into the insertion hole 31. The male screw member 34a is, for example, a set screw or the like. The male screw member 34a is columnar and has a male screw on the outer peripheral surface. The tip surface of the male screw member 34a contacts the locking portion 25 of the cutting insert 2 from the rear end side in the axial direction and from the outside in the radial direction. In the present embodiment, the tip surface of the male screw member 34a is planar and comes into surface contact with the locking portion 25.
In FIGS. 1 and 3, the female screw hole 33 and the male screw member 34a (regulating portion 34) are not shown.

[Chuck mechanism]
The constituent members of the chuck mechanism 4 are made of, for example, steel. As shown in FIGS. 1 to 5, the chuck mechanism 4 has a mounting cylinder portion 41 and a collet portion 42.

The mounting cylinder portion 41 has a cylindrical shape centered on the central axis C. The mounting cylinder portion 41 has a female screw portion 41a, a pushing portion 41b, a rib portion 41c, and a locking surface 41d.
The female screw portion 41a is arranged at the rear end portion in the axial direction of the inner peripheral surface of the mounting cylinder portion 41. The female screw portion 41a is screwed to the male screw portion 32a of the holder cylinder portion 32.

The pushing portion 41b is arranged at the tip portion in the axial direction of the inner peripheral surface of the mounting cylinder portion 41. The push-in portion 41b rotates the mounting cylinder portion 41 around the central axis C to increase the amount of screwing between the male screw portion 32a and the female screw portion 41a, and causes the collet portion 42 to move toward the rear end side in the axial direction. It can be pushed in. In the present embodiment, the pushing portion 41b has a tapered surface shape whose diameter increases toward the rear end side in the axial direction, and the receiving portion 42c described later of the collet portion 42 can be pushed toward the rear end side in the axial direction.

The rib portion 41c is arranged on the inner peripheral surface of the mounting cylinder portion 41, which is located between the female screw portion 41a and the pushing portion 41b in the axial direction. The rib portion 41c is an annular shape centered on the central axis C, projects radially inward from the inner peripheral surface of the mounting cylinder portion 41, and extends in the circumferential direction.

A plurality of locking surfaces 41d are provided on the outer peripheral surface of the mounting cylinder portion 41 at intervals in the circumferential direction. The locking surface 41d has a planar shape parallel to the central axis C and faces radially outward. A work tool such as a spanner (not shown) can be locked to the locking surface 41d.

As shown in FIG. 5, the collet portion 42 is a separate body from the mounting cylinder portion 41, that is, is configured by a member separate from the mounting cylinder portion 41. The collet portion 42 has a cylindrical shape centered on the central axis C and extends in the axial direction. A cutting insert 2 is inserted inside the collet portion 42. The cutting insert 2 projects from the collet portion 42 on both sides in the axial direction, that is, on the front end side and the rear end side, respectively. The collet portion 42 is arranged in the radial direction between the mounting cylinder portion 41 and the holder cylinder portion 32 and the cylindrical portion 24 of the cutting insert 2. The outer peripheral surface of the collet portion 42 is in contact with the inner peripheral surfaces of the mounting cylinder portion 41 and the holder cylinder portion 32, and the inner peripheral surface of the collet portion 42 is in contact with the outer peripheral surface of the cylindrical portion 24.

The collet portion 42 has a variable diameter, that is, it can be reduced in diameter and expanded in diameter. The collet portion 42 can move in the axial direction with respect to the mounting cylinder portion 41 and the holder cylinder portion 32 by changing the diameter. Specifically, as shown in FIG. 4, the collet portion 42 has a plurality of slits 42a arranged at intervals in the circumferential direction, and the collet portion 42a is widened by decreasing or increasing the width of the slits 42a. The diameter of 42 changes. In the present embodiment, as shown in FIG. 4, a plurality of slits 42a are arranged radially with the central axis C as the center when viewed from the axial direction. Although not shown in particular, when the cutting insert 2 is not inserted inside the collet portion 42, the collet portion 42 can be taken out from the inside of the mounting cylinder portion 41 by reducing the diameter of the collet portion 42. be. That is, the collet portion 42 can be attached to and detached from the mounting cylinder portion 41, and can be replaced with another collet portion 42 having a different inner diameter, for example.

As shown in FIG. 5, the collet portion 42 has an outer peripheral tapered surface 42b, a receiving portion 42c, and a groove portion 42d.
The outer peripheral tapered surface 42b is arranged on the outer peripheral surface of the collet portion 42. In the present embodiment, the outer peripheral tapered surface 42b is arranged on a portion of the outer peripheral surface of the collet portion 42 other than the tip portion in the axial direction. The outer peripheral tapered surface 42b has a tapered shape in which the outer diameter increases toward the tip side in the axial direction. The outer peripheral tapered surface 42b is slidably in contact with the inner peripheral tapered surface 32b of the holder cylinder portion 32.

The receiving portion 42c is arranged on the outer peripheral surface of the collet portion 42. In the present embodiment, the receiving portion 42c is arranged at the tip portion in the axial direction of the outer peripheral surface of the collet portion 42. The receiving portion 42c has a tapered surface shape whose diameter increases toward the rear end side in the axial direction. The receiving portion 42c is slidably in contact with the pushing portion 41b of the mounting cylinder portion 41.

As shown in FIG. 5, in a vertical cross-sectional view along the central axis C, the direction in which the receiving portion 42c is inclined with respect to the central axis C and the direction in which the outer peripheral tapered surface 42b is inclined with respect to the central axis C are mutually exclusive. different. In the present embodiment, the inclination angle of the receiving portion 42c with respect to the central axis C is larger than the inclination angle of the outer peripheral tapered surface 42b with respect to the central axis C. Further, the length of the outer peripheral tapered surface 42b in the axial direction is longer than the length of the receiving portion 42c in the axial direction.

The groove portion 42d is arranged on the outer peripheral surface of the collet portion 42, which is located between the outer peripheral tapered surface 42b and the receiving portion 42c in the axial direction. The groove portion 42d is an annular shape centered on the central axis C, is recessed inward in the radial direction from the outer peripheral surface of the collet portion 42, and extends in the circumferential direction. The rib portion 41c of the mounting cylinder portion 41 is inserted into the groove portion 42d. The rib portion 41c can move inside the groove portion 42d in a predetermined range in the axial direction and in the circumferential direction.

[Action and effect of this embodiment]
In the cutting tool 1A with replaceable cutting edge of the present embodiment described above, the cutting insert 2 is inserted inside the collet portion 42 having a cylindrical shape in the radial direction, and the locking portion 25 of the cutting insert 2 is inserted into the insertion hole 31 of the holder 3. By screwing the mounting cylinder portion 41 to the holder cylinder portion 32 in a state of being in contact with the male screw member 34a (regulating portion 34), the cutting insert 2 is clamped while being aligned with the holder 3, and the holder 3 is used. Is fixed to.

Specifically, by bringing the locking portion 25 of the cutting insert 2 into contact with the restricting portion 34 of the holder 3, the rotation of the cutting insert 2 with respect to the holder 3 around the central axis C and the movement toward the rear end side in the axial direction are restricted. Will be done. That is, the phase of the cutting insert 2 in the circumferential direction is aligned and the positioning in the axial direction (toward the rear end side) is performed.
From this state, when the mounting cylinder portion 41 is rotated around the central axis C to increase the screwing amount between the female screw portion 41a and the male screw portion 32a, the pushing portion 41b of the mounting cylinder portion 41 becomes the collet portion 42. Is pushed toward the rear end side in the axial direction. As a result, the collet portion 42 is reduced in diameter while the outer peripheral tapered surface 42b of the collet portion 42 and the inner peripheral tapered surface 32b of the holder cylinder portion 32 are in sliding contact with each other, and the inner peripheral surface of the collet portion 42 is a cylinder of the cutting insert 2. The portion 24 is pressed from the outside in the radial direction. That is, the collet portion 42 clamps the cutting insert 2 evenly in the circumferential direction while applying a pulling force toward the rear end side in the axial direction to the cutting insert 2.

According to the present embodiment, the insertion hole 31 and the holder cylinder portion 32 are coaxial with each other, and the cutting insert 2 is clamped by the collet portion 42 whose diameter is reduced by the sliding contact with the holder cylinder portion 32. , The cutting insert 2 can be accurately coaxially aligned with the insertion hole 31 of the holder 3.

Further, it is not necessary to provide the cylindrical portion 24 of the cutting insert 2 with a D-cut flat surface portion for contacting the tip of the screw member as in the conventional case, and according to the present embodiment, the rigidity of the cutting insert 2 is increased. Can be enhanced. Further, a large contact area between the outer peripheral surface of the cylindrical portion 24 and the inner peripheral surface of the collet portion 42 can be secured, that is, the collet portion 42 can hold the cutting insert 2 over the entire circumference around the central axis C, so that the cutting insert 2 can be used. Can be clamped stably. Further, according to the present embodiment, the tool rigidity is ensured evenly in the circumferential direction.

Further, when the collet portion 42 clamps the cutting insert 2, the collet portion 42 applies a pulling force toward the other side in the axial direction to the cutting insert 2, so that the locking portion 25 of the cutting insert 2 is a holder 3. The state of being abutted against the regulation unit 34 is maintained in good condition. Therefore, it is possible to prevent the cutting insert 2 from being displaced toward the tip end side in the axial direction during clamping. That is, in the present embodiment, the axial positioning accuracy of the cutting insert 2 is stably ensured before and after the clamp.
From the state where the locking portion 25 of the cutting insert 2 and the regulating portion 34 of the holder 3 are closely arranged with a gap between them, the mounting cylinder portion 41 is screwed to the holder cylinder portion 32, and the collet portion 42 It is also possible to move the cutting insert 2 toward the rear end side in the axial direction by using the pulling force to bring the locking portion 25 and the regulating portion 34 into contact with each other. In this case, the positioning accuracy of the cutting insert 2 is ensured, and the operability at the time of insert clamping is further improved.

Further, by replacing the collet portion 42, which is separate from the mounting cylinder portion 41, with another collet portion 42 having a different inner diameter, a plurality of types of cutting inserts 2 having different diameters for one type of holder 3 Can be used. Therefore, the cutting tool 1A having a replaceable cutting edge of the present embodiment can meet various cutting conditions and the like, and its versatility is enhanced.

Further, in the present embodiment, the cutting insert 2 can be clamped by rotating the mounting cylinder portion 41 from the front of the holder, for example, at the tool tip portion exposed from the machine tool M, and the operability is good. Further, since the cutting insert 2 is firmly clamped at the tip of the tool, the rigidity of the tool is enhanced, chatter vibration during cutting can be suppressed, and the machining accuracy is stably enhanced.

Further, in the present embodiment, the collet portion 42 has a plurality of slits 42a, and the diameter of the collet portion 42 changes as the width of these slits 42a decreases or increases.
In this case, the collet portion 42 can be reduced in diameter or expanded in diameter with a simple structure. The collet portion 42 allows the cutting insert 2 to be clamped uniformly and stably in the circumferential direction.

Further, in the present embodiment, the collet portion 42 has a tapered surface-shaped receiving portion 42c, the mounting cylinder portion 41 has a tapered surface-shaped pushing portion 41b, and the pushing portion 41b has the receiving portion 42c at the rear end in the axial direction. It can be pushed to the side.
In this case, even if the collet portion 42 is reduced in diameter by being pushed into the holder cylinder portion 32, the contact state between the tapered surface-shaped receiving portion 42c and the tapered surface-shaped pushing portion 41b is maintained satisfactorily. Therefore, the receiving portion 42c can be stably pushed toward the rear end side in the axial direction by the pushing portion 41b, and the cutting insert 2 can be stably clamped.

Further, in the present embodiment, the holder 3 has a female screw hole 33, and the regulating portion 34 is a male screw member 34a that is screwed into the female screw hole 33 and protrudes into the insertion hole 31.
In this case, by adjusting the screwing amount of the male screw member 34a into the female screw hole 33, the axial position where the locking portion 25 of the cutting insert 2 and the male screw member 34a (regulatory portion 34) come into contact is finely adjusted. can. Thereby, the axial position, that is, the protrusion amount of the cutting edge 23 of the cutting insert 2 can be finely adjusted.
Although not particularly shown, the holder 3 may have another screw member (fixing screw) that can come into contact with the outer peripheral surface of the male screw member 34a. In this case, by fixing the male screw member 34a by another screw member, the protrusion amount of the cutting edge 23 finely adjusted by the screwing amount of the male screw member 34a can be satisfactorily maintained.

[Other configurations included in the present invention]
The present invention is not limited to the above-described embodiment, and the configuration can be changed without departing from the spirit of the present invention, for example, as described below.

6 to 9 show first to fourth modified examples of the cutting tool 1A having a replaceable cutting edge described in the above-described embodiment. In the illustration of each modification, the same components as those in the above-described embodiment are designated by the same reference numerals, and the differences will be mainly described below.

FIG. 6 shows a cutting tool 1B with a replaceable cutting edge of the first modification. In this modification, a plurality of locking portions 25 are provided on the cutting insert 2 at intervals in the axial direction. The locking portion 25 is arranged on the outer peripheral portion of the rear end side portion of the cutting insert 2. Of the plurality of locking portions 25, the locking portion 25 located on the rearmost end side in the axial direction is provided so as to cut out a part of the rear end surface of the cutting insert 2. Each locking portion 25 is a substantially semicircular flat surface. The male screw member 34a (regulating portion 34) comes into contact with one of the plurality of locking portions 25 (surface contact).
According to this first modification, the cutting edge 23 of the cutting insert 2 is projected by appropriately selecting one locking portion 25 to be brought into contact with the restricting portion 34 of the holder 3 from the plurality of locking portions 25. The amount can be selected as appropriate. That is, it is easy to greatly change the protrusion amount of the cutting edge 23 by using one cutting insert 2.

FIG. 7 shows a cutting tool 1C with a replaceable cutting edge as a second modification. In this modification, the holder 3 has a pin hole 35 that opens to the outer peripheral surface of the holder 3 and the insertion hole 31, and the regulating portion 34 fits into the pin hole 35 and passes through the inside of the insertion hole 31. 34b. The pin hole 35 penetrates the holder 3 along a virtual plane (not shown) perpendicular to the central axis C. The pin hole 35 has a circular hole shape. In the illustrated example, the central axis of the pin hole 35 and the central axis C of the holder 3 are arranged at the twisted position. The pin member 34b has a columnar shape and is inserted into the pin hole 35. The pin member 34b contacts the locking portion 25 of the cutting insert 2 in the insertion hole 31 from the rear end side in the axial direction and from the outside in the radial direction. In this modification, a part of the outer peripheral surface of the pin member 34b is in line contact with the locking portion 25.
According to this second modification, the pin member 34b (regulatory portion 34) is suppressed from moving in the axial direction with respect to the holder 3, so that the axial position of the cutting edge 23 of the cutting insert 2, that is, the accuracy of the protrusion amount is accurate. However, it is stably secured.

FIG. 8 shows a cutting tool 1D with a replaceable cutting edge as a third modification. In this modification, the locking portion 25 is arranged on the rear end surface of the cutting insert 2. As shown in FIG. 8, the locking portion 25 has a V shape that opens toward the rear end side when viewed from the radial direction. The locking portion 25 has a pair of semicircular planes, and the pair of planes are connected so as to form an obtuse angle between them on the central axis C. Further, in this modification, the central axis of the pin hole 35 extends in the direction orthogonal to the central axis C of the holder 3, that is, in the radial direction. The pin member 34b fitted to the pin hole 35 is lined with a pair of planes of the locking portion 25 at two locations on the outer peripheral surface thereof, a portion located above the central axis C and a portion located below the central axis C. Contact.
According to this third modification, the pin member 34b (regulating portion 34) is suppressed from moving in the axial direction with respect to the holder 3, so that the axial position of the cutting edge 23 of the cutting insert 2, that is, the accuracy of the protrusion amount is accurate. However, it is stably secured. Further, when the cutting insert 2 is clamped, the force of the pin member 34b supporting the locking portion 25 also acts on the lower side and the upper side, so that the alignment accuracy of the cutting insert 2 becomes more stable. When the locking portion 25 is arranged on the rear end surface of the cutting insert 2 as in the second and third deformation examples, it is easy to increase the rigidity of the cutting insert 2.

FIG. 9 shows a cutting tool 1E with a replaceable cutting edge as a fourth modification. In this modification, a plurality of locking portions 25 are provided on the cutting insert 2 at intervals in the axial direction. The pin member 34b (regulating portion 34) comes into contact (line contact) with one of the plurality of locking portions 25. Further, the cutting insert 2 has a contact portion 26 that comes into contact with the pin member 34b from the rear end side in the axial direction. A plurality of abutting portions 26 are provided on the cutting insert 2 at intervals in the axial direction. The contact portion 26 is arranged on the outer peripheral portion of the rear end side portion of the cutting insert 2. Each contact portion 26 is a plane having a substantially semicircular shape. The pin member 34b makes contact (line contact) with one of the plurality of contact portions 26.
According to this fourth modification, the contact between the locking portion 25 and the pin member 34b (regulating portion 34) and the contact between the contact portion 26 and the pin member 34b cause the rear end of the cutting insert 2 in the axial direction. Movement to the side and tip side is restricted. For example, even when a force for pulling out the cutting insert 2 from the insertion hole 31 of the holder 3 toward the tip end side in the axial direction acts during cutting, the cutting insert 2 is suppressed from coming out.

Further, in the above-described embodiment and each modification, the receiving portion 42c of the collet portion 42 is slidably and directly in direct contact with the pushing portion 41b of the mounting cylinder portion 41, but the present invention is not limited to this. Although not particularly shown, the chuck mechanism 4 may have a bearing interposed between the pushing portion 41b and the collet portion 42 (the receiving portion 42c). The bearing is, for example, a rolling bearing such as a tapered ball bearing centered on the central axis C. The bearing may be a tapered tubular dry bearing or the like.
In this case, even if the mounting cylinder portion 41 is rotated around the central axis C when the cutting insert 2 is clamped, the collet portion 42 rotates because the bearing is provided between the pushing portion 41b and the collet portion 42. Is suppressed. That is, since rotational behavior is suppressed in the collet portion 42, only the pressing force (clamping force) from the outside in the radial direction and the pulling force toward the rear end side in the axial direction are applied to the cutting insert 2 via the collet portion 42. Can be made to act. Therefore, the phase alignment in the circumferential direction and the positioning in the axial direction of the cutting insert 2 can be accurately performed, and the load on each positioning element (regulating portion 34, locking portion 25, etc.) is reduced.

Further, in the above-described embodiment and each modification, an example in which the cutting insert 2 is, for example, an integrated type made of cemented carbide is given, but the present invention is not limited to this.
FIG. 10 is a top view showing a part of the cutting tool 1F with a replaceable cutting edge of the fifth modification. In this modification, the cutting insert 2 is made of an axially extending insert shank 2a made of, for example, steel or cemented carbide, and an axial tip of the insert shank 2a, for example, made of cemented carbide. It has a blade portion 2b and.
A rake surface 21, a flank surface 22, and a cutting edge 23 are arranged on the blade portion 2b. The blade portion 2b is fixed to the tip portion of the insert shank 2a by, for example, screwing or brazing. The blade portion 2b is located on the tip side of the holder 3 and the chuck mechanism 4 in the axial direction. A cylindrical portion 24, a locking portion 25, and a contact portion 26 are arranged on the insert shank 2a.
In this case, for example, the insert shank 2a can be made of a material having higher toughness and lower cost than the blade portion 2b. While reducing the tool cost, it is possible to further suppress the loss of the locking portion 25 and the contact portion 26.

The present invention may be combined with each of the configurations described in the above-described embodiments and modifications, and the configurations can be added, omitted, replaced, or otherwise changed without departing from the spirit of the present invention. .. Further, the present invention is not limited to the above-described embodiments and the like, but is limited only to the scope of claims.

According to the cutting tool with replaceable cutting edge of the present invention, the cutting insert can be accurately aligned with the holder, the cutting insert can be clamped stably, and the cutting insert is displaced to the tip side in the axial direction during clamping. It can be suppressed, and a plurality of types of cutting inserts having different diameters can be used for one type of holder, which enhances versatility. Therefore, it has industrial applicability.

1A, 1B, 1C, 1D, 1E, 1F ... Cutting tool with replaceable cutting edge 2 ... Cutting insert 3 ... Holder 4 ... Chuck mechanism 23 ... Cutting edge 24 ... Cylindrical part 25 ... Locking part 26 ... Contact part 31 ... Insertion hole 32 ... Holder cylinder part 32a ... Male screw part 32b ... Inner peripheral tapered surface 33 ... Female screw hole 34 ... Restriction part 34a ... Male screw member 34b ... Pin member 35 ... Pin hole 41 ... Mounting cylinder part 41a ... Female screw part 41b ... Pushing part 42 ... Collet part 42a ... Slit 42b ... Outer peripheral tapered surface 42c ... Receiving part C ... Central axis

Claims (9)

A shaft-shaped cutting insert that extends in the axial direction around the central axis,
A columnar holder having an insertion hole into which the cutting insert is inserted and extending in the axial direction,
A chuck mechanism for detachably fixing the cutting insert inserted into the insertion hole to the holder is provided.
The holder is
A holder cylinder portion located at the tip portion in the axial direction of the holder, arranged coaxially with the insertion hole, and having a male screw portion on the outer peripheral surface.
It has a regulating portion that contacts the cutting insert inside the insertion hole and regulates the rotation of the cutting insert around the central axis and the movement toward the rear end side in the axial direction.
The cutting insert is
A cylindrical portion whose at least a part is arranged inside the holder cylinder portion, and a cylindrical portion.
A locking portion that comes into contact with the restricting portion and
It has a cutting edge that protrudes toward the tip end side in the axial direction from the holder cylinder portion.
The chuck mechanism is
A mounting cylinder portion having a female screw portion screwed to the male screw portion on the inner peripheral surface, and a mounting cylinder portion.
A tubular shape that is separate from the mounting cylinder and is arranged between the mounting cylinder, the holder cylinder, and the cylinder in the radial direction orthogonal to the central axis, and has a variable diameter. With a collet part,
The holder cylinder portion has an inner peripheral tapered surface whose inner diameter increases toward the tip end side in the axial direction.
The collet portion has an outer peripheral tapered surface that has an outer diameter that increases toward the tip side in the axial direction and is slidably in contact with the inner peripheral tapered surface.
The mounting cylinder portion has a pushing portion capable of pushing the collet portion toward the rear end side in the axial direction when the amount of screwing between the male screw portion and the female screw portion is increased.
Cutting tool with replaceable cutting edge. The collet portion has a plurality of slits arranged at intervals in the circumferential direction around the central axis.
As the width of the slit decreases or increases, the diameter of the collet portion changes.
The cutting tool with a replaceable cutting edge according to claim 1. The collet portion has a tapered surface-shaped receiving portion that is arranged on the outer peripheral surface of the collet portion and whose diameter increases toward the rear end side in the axial direction.
The pushing portion is arranged on the inner peripheral surface of the mounting cylinder portion and has a tapered surface shape whose diameter increases toward the rear end side in the axial direction, and the receiving portion can be pushed toward the rear end side in the axial direction. Is,
The cutting tool with a replaceable cutting edge according to claim 1 or 2. A plurality of the locking portions are provided on the cutting insert at intervals in the axial direction.
The cutting tool with a replaceable cutting edge according to any one of claims 1 to 3. The holder has a female screw hole that is open to the outer peripheral surface of the holder and the insertion hole, and is located on the tip end side in the axial direction toward the inside in the radial direction.
The restricting portion is a male screw member that is screwed into the female screw hole and protrudes into the insertion hole.
The cutting tool with a replaceable cutting edge according to any one of claims 1 to 4. The holder has a pin hole that opens to the outer peripheral surface of the holder and the insertion hole.
The restricting portion is a pin member that fits into the pin hole and passes through the inside of the insertion hole.
The cutting tool with a replaceable cutting edge according to any one of claims 1 to 4. The cutting insert has an abutting portion that contacts the pin member from the rear end side in the axial direction.
The cutting tool with a replaceable cutting edge according to claim 6. The chuck mechanism has a bearing interposed between the push-in portion and the collet portion.
The cutting tool with a replaceable cutting edge according to any one of claims 1 to 7. The cutting insert is
A shaft-shaped insert shank extending in the axial direction and
With a blade portion disposed at the axial tip portion of the insert shank,
The cutting edge is arranged on the blade portion.
The columnar portion and the locking portion are arranged on the insert shank.
The cutting tool with a replaceable cutting edge according to any one of claims 1 to 8.

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