JP2021104570A - Cutting edge replaceable cutting tool with chip breaker piece - Google Patents

Abstract

To control the outflow direction of cutting chips even when extended cutting chips are generated while preventing the frictional resistance due to the scratch of the cutting chips from increasing more than necessary.SOLUTION: A cutting insert 6 in which an insert cutting blade 6a is formed on an intersection ridge line part between a rake surface 6b and a flank 6c is attached to an insert attachment seat 4 formed on the tip of a tool body 1 with the rake surface 6b facing the outer peripheral side of the tool body 1. Across the tip of the tool body 1 and the cutting insert 6, an insertion hole 10 to which a columnar shaft-shaped chip breaker piece 9 is inserted is formed and opened on the rake surface 6b. The chip breaker piece 9 is inserted to the insertion hole 10 by protruding the tip 9a of the chip breaker piece 9 from an opening 10a of the insertion hole 10 on the rake surface 6b and is supported so as to be rotationally driven around the centerline axis C of the chip breaker piece 9.SELECTED DRAWING: Figure 7

Description

In the present invention, a cutting insert having an insert cutting edge formed at an intersection ridge between a rake surface and a flank on an insert mounting seat formed at the tip of a tool body has a rake surface on the outer peripheral side of the tool body. It relates to a cutting tool with a replaceable cutting edge with a tip breaker piece, which is detachably attached to the rake face and has a tip breaker piece on the rake face.

As such a cutting tool with a replaceable cutting edge with a chip breaker piece, for example, Patent Document 1 states that the entire cutting tool has a flat plate shape and the shape in a plan view is a shape in which a regular polygonal corner is cut out. On the cutout surface of each corner, a cutting edge exchangeable cutting tool in which a chip breaker piece having chip breaker walls having different magnitudes of chip breaking action is attached to a rake surface is described.

Further, as a tip-replaceable cutting tool with a tip breaker piece in which the tip breaker piece is also attached to the rake face, Patent Document 2 describes a round tip having a clamp hole in the center in a circular shape in a plan view on the tip seat of the tool body. A tip breaker piece having a clamp hole at a position eccentric from the center in a circular shape in a plan view is provided on the round tip, and the round tip and the tip breaker piece are clamped through the clamp holes to form a round tip. A cutting edge replaceable bite provided with a clamp screw for fixing the tip breaker piece to the tip seat is also described.

However, in these cutting tools with replaceable cutting edges with tip breaker pieces as described in Patent Documents 1 and 2, since the tip breaker piece is fixed to the rake face of the cutting edge, the tip breaker piece and chips are violently rubbed. Therefore, not only the chip breaker piece is significantly worn, but also the cutting resistance is increased due to the frictional resistance between the chip breaker piece and the chips, so-called chattering vibration is likely to occur, and the machined surface accuracy and the machined surface roughness of the work material are rough. There was a problem of exacerbating the problem.

Therefore, in Patent Document 3, in order to reduce such frictional resistance, a tool body (holder body) to which a cutting insert is detachably attached to a tip portion and an upper surface as a rake surface of the cutting insert are described. A tip breaker piece that is attached and has a wall surface that slopes downward toward the cutting edge side of the cutting insert, and is configured to bend chips extending along the rake face by the wall surface. A type cutting tool in which a rotating body that can rotate in the direction in which chips extend is provided on the wall surface of the chip breaker piece around a rotation axis parallel to the rake face is described.

JP-A-59-224203 Jikkai Sho 63-131306 Jikkenhei 1-1701 No. 501

However, even in the cutting tool with a replaceable cutting edge with a tip breaker piece as described in Patent Documents 1 to 3, the chips generated by the cutting edge tend to extend especially when cutting a soft work material. Therefore, it becomes difficult to control the outflow direction of chips. For this reason, the extended chips are entangled with the tool body and the cutting work is interrupted to remove the chips, hindering stable cutting, or damaging the machined surface of the work material, impairing the machined surface accuracy and machined surface roughness. There is a risk of

In particular, the cutting tool with a tip breaker piece and a replaceable cutting edge described in Patent Document 3 is intended to reduce the frictional resistance by rolling contact of chips with the surface of a rotating body, so that the frictional resistance to the tool body is reduced. As it is reduced, the frictional resistance given to the chips also decreases. For this reason, it becomes more difficult to control the outflow direction of the chips by giving frictional resistance to the chips that are slightly stretched.

The present invention has been made under such a background, and while preventing the frictional resistance due to scraping of chips from increasing more than necessary, the outflow direction of chips can be controlled even when chips that are slightly stretched are generated. It is an object of the present invention to provide a cutting tool with a replaceable cutting edge with a tip breaker piece that can be controlled.

In order to solve the above problems and achieve such an object, the present invention has an insert cutting edge formed at the tip of the tool body at the intersection ridge between the rake face and the flank. The formed cutting insert is detachably attached with the rake face facing the outer peripheral side of the tool body, and a cylindrical shaft-shaped tip breaker piece is inserted from the tip of the tool body to the cutting insert. An insertion hole is formed and opens in the rake surface, and the tip breaker piece is inserted into the insertion hole by projecting the tip of the tip breaker piece from the opening of the insertion hole in the rake surface. The tip breaker piece is rotatably supported around the central axis of the chip breaker piece.

In the cutting tool with a tip breaker piece configured in this way, the shaft-shaped tip breaker piece whose tip protrudes from the opening on the rake face of the cutting insert can be rotationally driven around its central axis. By bringing the tip breaker piece into contact with chips while rotating it, it is possible to prevent the tip breaker piece from being worn and to prevent the cutting resistance from becoming larger than necessary. It is possible to prevent deterioration of machined surface accuracy and machined surface roughness.

The tip breaker piece is thus inserted into the insertion hole so that the tip portion protrudes from the rake face of the insert cutting edge of the cutting insert, and is rotationally driven around the central axis extending in the direction intersecting the rake face. Therefore, even if chips that are slightly stretched are generated when cutting a soft work material, the tip is projected in the outflow direction of the chips and rotationally driven to give appropriate frictional resistance to the chips. The outflow direction can be controlled. For this reason, it is possible to prevent a situation in which the cutting chips are entangled with the tool body and the cutting process is interrupted.

Here, the chip breaker piece may be rotationally driven by a rotary drive mechanism such as a motor, but in this case, a relatively large space for accommodating such a rotary drive mechanism is provided at the tip of the tool body. It will have to be provided. Therefore, a coolant hole to which coolant is supplied is formed from the tip of the tool body to the cutting insert, and the coolant hole is opened so as to coincide with the opening on the rake face of the insertion hole. By rotationally driving the breaker piece with the coolant supplied to the coolant hole, it is possible to avoid requiring such a large space at the tip of the tool body.

Moreover, by matching the opening on the rake face of the coolant hole with the opening on the rake face of the insertion hole in this way, it is possible to more reliably prevent the tip of the chip breaker piece from being worn and the outflow of chips. The direction can also be controlled more stably. The coolant may be a liquid such as a cutting fluid or a gas such as compressed air.

In order to rotationally drive the chip breaker piece with the coolant in this way, a rotary blade projecting on the outer peripheral side in the radial direction with respect to the central axis is provided at the rear end portion of the chip breaker piece, and the coolant hole is inserted. The chip breaker piece may be rotationally driven by injecting coolant onto the rotary blades so as to communicate with the holes. In this case, the rotation speed of the chip breaker piece can be adjusted by changing the supply pressure of the coolant.

Further, in addition to driving the chip breaker piece to rotate in this way, the chip breaker piece may be made capable of advancing and retreating with a constant stroke in the central axis direction. In this case, when the chip breaker piece advances in the direction of the central axis and protrudes, the tip portion can give a striking force to the chips, so that the impact of this striking force can be used to divide the chips. It becomes.

In order to enable the tip breaker piece to be moved forward and backward in this way, a pin protruding outward in the radial direction with respect to the central axis is provided at the rear end of the tip breaker piece, and the tip of the tool body is provided with a pin. On the peripheral surface of the inner peripheral portion of the insertion hole facing the central axis direction, a guide surface that is uneven in the central axis direction as the circumferential direction is provided is provided, and the pin rotates while being in sliding contact with the guide surface. The chip breaker piece may be made capable of advancing and retreating with a constant stroke in the direction of the central axis. The tip breaker piece can be moved forward and backward together with the pin according to the unevenness of the guide surface.

Further, by providing a chip breaker piece cutting blade at the tip of the chip breaker piece protruding from the opening of the insertion hole on the rake face, the chip breaker piece cutting blade can also be used to divide chips. This makes it possible to more reliably prevent a situation in which the cutting process is interrupted due to being entangled with the tool body even when chips that are slightly stretched are generated.

As described above, according to the present invention, it is possible to prevent the frictional resistance due to scraping of chips from increasing more than necessary, and to prevent deterioration of the machined surface accuracy and machined surface roughness of the work material due to chattering vibration. Even when chips that are slightly stretched are generated, the outflow direction of the chips can be controlled to prevent the cutting from being interrupted due to the entanglement of the chips with the tool body, and high-precision cutting is stable. It becomes possible to do it.

It is a perspective view which shows the 1st Embodiment of this invention. It is a front view of the embodiment shown in FIG. It is a right side view in FIG. It is a left side view in FIG. It is a top view in FIG. It is a bottom view in FIG. It is an enlarged perspective view of the tip portion (cutting edge portion) in the embodiment shown in FIG. It is a partially cutaway perspective view of the ZZ cross section in FIG. It is a perspective perspective view which shows the insertion hole, the coolant hole and the bottom surface of the insert mounting seat in the embodiment shown in FIG. It is an exploded perspective view of the chip breaker piece in the embodiment shown in FIG. It is a perspective view which shows the 1st modification of the chip breaker piece in the embodiment shown in FIG. It is a perspective view which shows the 2nd modification of the chip breaker piece in the embodiment shown in FIG. It is a perspective view which shows the 3rd modification of the chip breaker piece in the embodiment shown in FIG. It is a partially cutaway perspective view corresponding to the ZZ cross section in FIG. 1 of the second embodiment of the present invention. It is an exploded perspective view of the chip breaker piece and the bearing in the embodiment shown in FIG. 14 (however, the first bearing is shown in half along the central axis of the chip breaker piece for the sake of explanation).

1 to 10 show a first embodiment of the present invention, and the present invention is applied to a cutting edge replaceable cutting tool in the same manner as the cutting tool with a replaceable cutting edge described in Patent Documents 1 to 3. It shows the case. In the present embodiment, the tool body 1 is formed of a metal material such as a steel material, and has a rear end portion (upper right portion in FIG. 1, right portion in FIGS. 3, 5, and 6; left side in FIG. 4). The portion) is a square prismatic shank portion 2, and the tip portion (the lower left portion in FIG. 1, the left portion in FIGS. 3, 5, and 6; the right portion in FIG. 4) is the tool body. It is a cutting edge portion 3 projecting to the right side surface side of the shank portion 2 when viewed from the tip end side of 1.

In the cutting tool with a tip breaker piece of the present embodiment, which is a cutting tool with a replaceable cutting edge as described above, the shank portion 2 is fixed to the tool post of the machine tool and formed at the tip of the cutting edge portion 3. The rotating work material (not shown) is turned by the insert cutting edge 6a of the cutting insert 6 which is clamped to the insert mounting seat 4 by the clamp member (clamp piece) 5 and is detachably attached. The upper surface of the tip end portion of the cutting edge portion 3 is inclined toward the lower surface side toward the tip end side.

The cutting insert 6 is formed in the shape of a rhombus plate in this embodiment by a metal material harder than the tool body 1 such as cemented carbide, and one rhombus surface is formed as a rake surface 6b on the outer peripheral side of the tool body 1. (Upper side in FIGS. 1 to 3)), and four side surfaces arranged around the rake face 6b are defined as flanks 6c, and the above-mentioned crossing ridges between the rake faces 6b and the flanks 6c. The insert cutting edge 6a is formed. Further, a blind hole-shaped recess 6d is formed in the central portion of the rake face 6b.

The cutting insert 6 of the present embodiment is a negative type cutting insert in which the flank surface 6c extends in a direction perpendicular to the rake face 6b, and is perpendicular to the rake face 6b connecting the rhombic obtuse angle portions formed by the rake face 6b. It has a symmetrical shape with respect to the plane. Further, a concave groove-shaped tip breaker groove 6e is formed around the acute-angled portion of the rake face 6b so that it retracts and then protrudes as it moves away from the insert cutting edge 6a. When such a cutting insert 6 is used for turning as described above, the insert cutting edge 6a around the acute-angled corner portion of the diamond-shaped rake face 6b is exclusively cut into the work material for cutting. used.

The insert mounting seat 4 is a recess formed so as to open at the tip of the upper surface of the cutting edge portion 3, and has a diamond-shaped bottom surface 4a having substantially the same shape and size as the rake face 6b of the cutting insert 6 and the bottom surface thereof. It is provided with two wall surfaces 4b that rise perpendicularly to the bottom surface 4a from two edge portions intersecting the acute-angled corners on the rear end side of the cutting edge portion 3 of 4a and reach the upper surface of the cutting edge portion 3. The bottom surface 4a is inclined toward the lower surface side in parallel with the upper surface of the tip end portion of the cutting edge portion 3 toward the tip end side, and the bottom surface 4a is located at the center of the bottom surface 4a as shown in FIGS. 8 and 9. A columnar convex portion 4c that projects perpendicularly to 4a is formed.

The bottom surface 4a of the insert mounting seat 4 is made of metal such as steel and has a rhombus shape similar to the rake surface 6b of the cutting insert 6 and the bottom surface 4a of the insert mounting seat 4 which is substantially the same size or slightly smaller. A plate-shaped sheet member 7 having a thickness thinner than that of the cutting insert 6 is placed on the formed sheet member 7.

At the center of the diamond-shaped surface of the seat member 7, a seat mounting hole 7a into which the convex portion 4c of the bottom surface 4a of the insert mounting seat 4 is fitted is formed so as to penetrate the seat member 7. Thus, the convex portion 4c Is fitted into the seat mounting hole 7a and placed on the bottom surface 4a of the insert mounting seat 4, and the seat member 7 is fixed with the diamond-shaped surface of the lower surface in close contact with the bottom surface 4a of the insert mounting seat 4.

Further, in the upper part of the cutting edge portion 3, on the rear end side of the tool body 1 of the insert mounting seat 4, in a plan view perpendicular to the bottom surface 4a of the insert mounting seat 4, the two wall surfaces 4b of the insert mounting seat 4 A screw hole (not shown) is formed so as to have a center line at a position slightly distant from the bisector. The upper end of the screw hole is open on the upper surface of the cutting edge portion 3.

Further, the rear end surface 3a of the upper portion of the cutting edge portion 3 is an inclined surface that inclines toward the lower end side of the cutting edge portion 3 toward the rear end side as shown in FIG. Furthermore, a pin hole 3b is formed on the rear end surface 3a of the upper portion of the cutting edge portion 3 in parallel with the screw hole at a distance from the screw hole to the rear end side.

On the other hand, the clamp member 5 in the present embodiment is formed of a metal material such as a steel material so that the rear end portion is wide in a plan view and the tip portion is narrower toward the tip side. Further, a protruding wall portion 5a having a front wall surface that projects upward in a convex curved surface shape toward the rear end side is formed on the upper portion of the clamp member 5 in the central portion between the rear end portion and the front end portion. There is.

As shown in FIGS. 1 to 5, 7 and 8, such a clamping member 5 is attached to the upper surface of the cutting edge portion 3 to clamp the cutting insert 6. Here, with the clamp member 5 attached to the upper surface of the cutting edge portion 3 on the rear end side of the protruding wall portion 5a of the clamp member 5, the cutting edge portion penetrates the clamp member 5 vertically. A through hole 5b communicating with the screw hole of No. 3 is formed.

The through hole 5b has a long hole shape having a long axis in the direction from the screw hole on the upper surface of the cutting edge portion 3 toward the pin hole 3b in the plan view. The periphery of the opening of the through hole 5b on the rear end side of the protruding wall portion 5a on the upper surface of the clamp member 5 is formed in a flat shape perpendicular to the through hole 5b.

Further, the rear end portion of the clamp member 5 extends downward toward the rear end side, and the lower surface 5c of the rear end portion is the upper rear end surface 3a which is an inclined surface of the cutting edge portion 3. As shown in FIG. 8, the clamp member 5 is attached to the upper surface of the cutting edge portion 3 as described above, with an inclined surface that is equal to the inclination formed by the eggplant and is inclined downward toward the rear end side. It is possible to make sliding contact with the rear end surface 3a.

Further, a pin (not shown) projecting downward in parallel with the through hole 5b is formed on the lower surface 5c of the rear end portion, and the clamp member 5 is also attached to the upper surface of the cutting edge portion 3 in this pin. In this state, it can be inserted into the pin hole 3b of the cutting edge portion 3. Further, a through hole 5b and a clamp pin 5d projecting downward in parallel with the pin are also formed on the lower surface of the tip portion of the clamp member 5.

Furthermore, a male screw portion (not shown) of the clamp screw 8 is inserted into the through hole 5b of the clamp member 5, and the male screw portion of the clamp screw 8 is screwed into the screw hole of the cutting edge portion 3 to clamp the clamp. The member 5 is attached to the upper surface of the cutting edge portion 3. At the upper end of the clamp screw 8, a disk-shaped head 8a having a convex spherical surface on the upper surface having a diameter larger than the width and radius of the through hole 5b is formed, and the lower surface of the head 8a is male. It has a flat shape perpendicular to the center line of the threaded portion. Further, a polygonal engaging hole 8b that can be engaged with a work tool such as a wrench is formed in the center of the upper surface of the head 8a.

In order to clamp the cutting insert 6 with such a clamp member 5 and the clamp screw 8 and attach it to the insert mounting seat 4 detachably, first, the diamond-shaped surface opposite to the rake face 6b of the cutting insert 6 is attached to the insert mounting seat 4. The insert mounting seat 4 has two flanks 6c that intersect the acute angle portion of the rake face 6b facing the rear end side of the cutting edge portion 3 while being brought into close contact with the seat member 7 placed and fixed on the bottom surface 4a of the cutting blade portion 3. The cutting insert 6 is seated on the insert mounting seat 4 by abutting each of the two wall surfaces 4b.

Next, the clamp pin 5d of the clamp member 5 is inserted into the recess 6d of the rake face 6b of the cutting insert 6, the pin is inserted into the pin hole 3b of the cutting edge portion 3, and the clamp member 5 is inserted into the cutting edge portion 3. Place on the top surface. Then, by engaging a work tool such as a wrench with the engaging hole 8b of the clamp screw 8 in which the male screw portion is inserted into the through hole 5b and rotating the clamp screw 8, the male screw portion is made into the screw hole. Screw it into.

When the male screw portion is screwed in this way, the lower surface of the head 8a of the clamp screw 8 comes into close contact with the vicinity of the opening of the through hole 5b on the upper surface of the clamp member 5 of the through hole 5b, and the lower surface 5c of the rear end portion of the clamp member 5 Is in sliding contact with the rear end surface 3a of the upper part of the cutting edge portion 3. Therefore, when the male screw portion of the clamp screw 8 is further screwed into the screw hole from this state, the clamp member 5 has a lower surface 5c of the rear end portion of the clamp member 5 and a rear end surface of the upper portion of the cutting edge portion 3. It moves below the cutting edge portion 3 while moving toward the rear end side along the inclination of 3a.

Along with this, the portion on the rear end side of the clamp pin 5d presses the inner peripheral portion on the rear end side of the recess 6d opened on the rake face 6b of the cutting insert 6 toward the lower rear end side of the cutting edge portion 3, so that cutting is performed. In the insert 6, the rhombic surface opposite to the rake surface 6b is pressed against the bottom surface 4a of the insert mounting seat 4 via the seat member 7, and the acute-angled portion of the rake surface 6b facing the rear end side of the cutting edge portion 3. The two flanks 6c intersecting with each other are pressed against the two wall surfaces 4b of the insert mounting seat 4, and the cutting insert 6 is fixed to the insert mounting seat 4.

In the cutting insert 6 fixed to the insert mounting seat 4 in this way, of the rake surfaces 6b, an acute angle at which two flanks 6c opposite to the flanks 6c pressed against the two wall surfaces 4b intersect. The insert cutting edge 6a around the corner portion projects toward the tip end side of the cutting edge portion 3 and is cut into the work material, and is used for cutting. Further, in order to remove the cutting insert 6 from the insert mounting seat 4, the clamp screw 8 may be loosened.

In the cutting tool with a tip breaker piece configured in this way, a cylindrical shaft-shaped tip breaker piece 9 is inserted from the cutting edge portion 3 which is the tip portion of the tool body 1 to the cutting insert 6 as shown in FIG. An insertion hole 10 is formed and opens in the rake face 6b of the cutting insert 6.

The tip breaker piece 9 is inserted into the insertion hole 10 by projecting the tip portion 9a of the tip breaker piece 9 from the opening 10a of the insertion hole 10 on the rake face 6b as shown in FIG. It is supported so that it can be rotationally driven around the central axis C of the piece 9.

The insertion hole 10 is formed in the cutting edge portion 3 so that the inner diameter thereof is gradually reduced in three steps from the lower surface of the cutting edge portion 3 toward the opening 10a side of the cutting insert 6 to the rake face 6b. The large-diameter portion 10b on the lower surface side of the cutting edge portion 3, the medium-diameter portion 10c communicating with the opening 10a side of the large-diameter portion 10b, and the medium-diameter portion 10c communicating with the opening 10a side of the medium-diameter portion 10c are inserted. It is provided with a small diameter portion 10d that opens to the bottom surface 4a of the mounting seat 4.

The large-diameter portion 10b, the medium-diameter portion 10c, and the small-diameter portion 10d have a circular cross section perpendicular to the center line of the insertion hole 10 coaxial with the center axis C of the chip breaker piece 9. It is formed, and its inner diameter is constant. Further, the center line of the insertion hole 10 is a rake face from the lower surface of the cutting edge portion 3 on a plane orthogonal to the rake face 6b along the bisector connecting the acute angle portions of the rake face 6b of the cutting insert 6. It extends toward the tip end side of the cutting edge portion 3 toward the opening 10a side of the insertion hole 10 in 6b.

Further, as shown in FIG. 8, the insertion hole 10 extends in communication with the coolant hole 11 described later in the portion of the sheet member 7 and the cutting insert 6, and the cross section orthogonal to the center line of the insertion hole 10 is described above. It is formed in an oval shape extending in the direction of the bisector, and in the portion of the cutting insert 6, the cross section in the plane orthogonal to the rake face 6b along the bisector increases toward the opening 10a side. It is formed in a narrow triangular shape. Further, as shown in FIG. 7, the opening 10a in the rake face 6b of the cutting insert 6 of the insertion hole 10 is circular in the vicinity of the acute angle portion where the insert cutting edge 6a used for cutting the cutting insert 6 intersects. It is open to.

The tip breaker piece 9 that is inserted into the insertion hole 10 and supported so as to be rotationally driveable is a multi-stage circle in which the tip portion 9a is formed, as shown in FIG. 10 in order from the front end side to the rear end side. A columnar breaker piece main body 9A, a cylindrical connecting member 9B connected to the rear end portion of the breaker piece main body 9A, a multi-stage cylindrical shaft member 9C to which the connecting member 9B is connected to the tip end portion, and the like. It includes a cylindrical rotating member 9D attached to the outer periphery of the shaft member 9C.

Like the cutting insert 6, the breaker piece body 9A is integrally formed of a hard material such as cemented carbide, and the tip portion 9a has a convex hemispherical shape in the present embodiment and is on the rear end side of the tip portion 9a. Is a long cylindrical shaft-shaped portion 9b having a diameter equal to the diameter of the hemisphere formed by the tip portion 9a. Further, on the rear end side of the cylindrical shaft-shaped portion 9b, a cylindrical connecting shaft portion 9d having a diameter larger than that of the cylindrical shaft-shaped portion 9b is coaxially formed via a flange-shaped portion 9c.

Further, the connecting member 9B, the shaft member 9C, and the rotating member 9D are formed of a metal material such as a steel material like the tool body 1. Of these, the cylindrical connecting member 9B has an outer diameter equal to that of the flange-shaped portion 9c of the breaker piece main body 9A, and the inner diameter is set to a size that allows the connecting shaft portion 9d of the breaker piece main body 9A to be fitted. ..

Further, the tip portion of the shaft member 9C has a columnar shape centered on the central axis C having an outer diameter equal to the outer diameter of the connecting shaft portion 9d of the breaker piece main body 9A, and can be fitted into the inner peripheral portion of the connecting member 9B. At the rear end of the shaft member 9C, both ends of the central axis C have an outer diameter equal to the outer diameter of the connecting member 9B and the outer diameter of the collar-shaped portion 9c of the breaker piece main body 9A. It is said to be a cylinder centered on.

Furthermore, a plurality of keys 9e having the same shape and the same size protruding toward the outer peripheral side are formed between both ends of the rear end portion of the shaft member 9C. These keys 9e extend in the central axis C direction at equal intervals in the circumferential direction, and the individual keys 9e become narrower toward the outer peripheral side of the shaft member 9C in the cross section orthogonal to the central axis C. It has an isosceles right triangle shape, but the apex portion of the outermost circumference is formed in a convex arc shape.

On the other hand, a key groove 9f into which a plurality of keys 9e of the shaft member 9C are fitted is formed in the inner peripheral portion of the cylindrical rotating member 9D. Therefore, these key grooves 9f also have an isosceles triangle shape whose cross section orthogonal to the central axis C of each key groove 9f becomes narrower toward the outer peripheral side of the rotating member 9D, but the apex portion of the outermost circumference is It is formed in a convex arc shape. The outer peripheral surfaces of both ends of the rotating member 9D in the central axis C direction are cylindrical surfaces having the same outer diameter as the central axis C.

Further, at the central portion of the outer peripheral portion of the rotating member 9D in the central axis C direction, a rotary blade 9g projecting radially to the outer peripheral side with respect to the central axis C is provided. The rotary blade 9g is formed in a thin flat plate shape twisted around the central axis C so as to be directed toward the tip end side of the chip breaker piece 9 in the central axis C direction and toward the coolant supply direction F side described later. , A plurality of rotary blades 9g are integrally provided on the rotary member 9D at equal intervals in the circumferential direction of the rotary member 9D.

In such a chip breaker piece 9, a shaft member 9C is attached to the inner peripheral portion of the rotating member 9D while the key 9e is fitted into the key groove 9f, and the tip end portion of the shaft member 9C is the rear end of the connecting member 9B. It is assembled by being fitted and attached to the inner peripheral portion, and the connecting shaft portion 9d of the breaker piece main body 9A is fitted and attached to the tip inner peripheral portion of the connecting member 9B. At this time, both ends of the shaft member 9C in the central axis C direction are projected from both end faces of the rotating member 9D in the central axis C direction.

The tip breaker piece 9 assembled in this way is inserted into the insertion hole 10 through the opening of the insertion hole 10 on the lower surface of the cutting edge portion 3 with the tip portion 9a facing the cutting insert 6 side, and the rotating member 9D is inserted. Along with being disposed in the large diameter portion 10b of the insertion hole 10, the portion of the shaft member 9C on the tip side of the key groove 9f is disposed in the medium diameter portion 10c, and the connecting shaft portion 9d to the breaker piece main body 9A. Up to the flange-shaped portion 9c is arranged in the small diameter portion 10d. Further, the cylindrical shaft-shaped portion 9b of the breaker piece main body 9A is inserted into the insertion hole 10 of the seat member 7 and the cutting insert 6, and the tip portion 9a protrudes from the opening 10a.

Here, between the outer peripheral surfaces of both ends of the rotating member 9D arranged in the large-diameter portion 10b of the insertion hole 10 in the central axis C direction and the inner peripheral surface of the large-diameter portion 10b, the rotating member 9D is described above. An annular bearing 12 having a square cross section made of plastic or the like having an inner diameter slightly larger than the outer diameters of both ends is attached to and intervened on the inner peripheral surface of the large diameter portion 10b by tightening or the like. The tip breaker piece 9 is rotatable around the central axis C.

Further, between the outer peripheral surface of the tip portion of the key groove 9f of the shaft member 9C arranged in the middle diameter portion 10c and the inner peripheral surface of the middle diameter portion 10c, the outer diameter of the tip portion of the shaft member 9C An annular ring 13 having a square cross section made of cemented carbide or the like having a very slightly large inner diameter is fitted into the medium diameter portion 10c and interposed.

Further, in the opening of the large diameter portion 10b of the insertion hole 10 on the lower surface of the cutting edge portion 3, a cylindrical support member holder 14b detachably attached to the lower surface of the cutting edge portion 3 by a mounting bolt 14a is provided. It has been inserted. Further, a support member 14 such as a ball plunger is screwed and attached to the inner peripheral portion of the cylindrical support member holder 14b.

Then, the tip portion of the support member 14 comes into contact with the rear end surface of the rear end portion of the shaft member 9C protruding from the rear end surface of the rotating member 9D in the central axis C direction, so that the chip breaker piece 9 is formed by the shaft member 9C. The rear end portion and the tip portion of the rotating member 9D with respect to the rotating blade 9g are sandwiched between the supporting member 14 and the end surface of the ring 13 facing the lower surface side of the cutting edge portion 3 so as to be sandwiched in the direction of the central axis C. It is supported in the insertion hole 10 while being adjusted in position.

In this embodiment, the coolant supplied to the coolant hole 11 described above is used to rotationally drive the chip breaker piece 9 rotatably supported in this way around the central axis C. Here, the rear end surface 3a of the upper surface of the cutting edge portion 3 of the tool body 1 is one of the planes orthogonal to the rake face 6b along the bisector connecting the acute angle portions of the rake face 6b of the cutting insert 6. The coolant supply hole 11a of the coolant hole 11 is opened on the side (upper side in FIG. 5). The coolant may be a liquid such as a cutting fluid or a gas such as compressed air.

Then, as shown in FIG. 9, the coolant supply hole 11a is reduced in diameter by one step toward the tip end side of the cutting edge portion 3 toward the coolant supply direction F, and is coaxial with the central axis C of the chip breaker piece 9. A rotating member arranged in the large diameter portion 10b along a tangent line of a circle formed by this plane and the inner peripheral surface of the large diameter portion 10b of the insertion hole 10 on a plane orthogonal to the center line of the insertion hole 10. It opens in the inner peripheral surface of the large diameter portion 10b at the position of the rotating blade 9g of 9D and extends so as to communicate with the insertion hole 10.

On the other hand, on the inner peripheral surface of the large diameter portion 10b on the coolant supply direction F side of the opening of the coolant supply hole 11a, the position of the rotary blade 9g of the rotating member 9D also arranged in the large diameter portion 10b is located. The first coolant discharge hole 11b is open. The first coolant discharge hole 11b is the other side with respect to a plane orthogonal to the rake face 6b along the bisector connecting the acute angle portions of the rake face 6b of the cutting insert 6 parallel to the lower surface of the cutting edge portion 3. It extends to (lower side in FIG. 5) and opens to the side surface of the cutting edge portion 3 on the other side.

Further, the lower surface of the cutting edge portion 3 intersects and communicates with the first coolant discharge hole 11b and extends toward the bottom surface 4a of the insert mounting seat 4, and the convex portion 4c formed on the bottom surface 4a. A second coolant discharge hole 11c communicating with the insertion hole 10 formed in the sheet member 7 and the cutting insert 6 is formed on the tip side. Here, the opening on the side surface and the opening on the lower surface of the cutting edge portion 3 on the other side of the cutting edge portion 3 than the portion where the first and second coolant discharge holes 11b and 11c communicate with each other are made of a filling screw, a plug, or the like. It is sealed by the sealing member 15.

In a cutting tool with a chip breaker piece configured in this way, when coolant is supplied from the coolant supply hole 11a to the coolant hole 11 in the coolant supply direction F during cutting, the supplied coolant is supplied from the coolant supply hole 11a to the insertion hole 10 The tip breaker piece 9 is tangential to the rotating blade 9g of the rotating member 9D arranged on the large-diameter portion 10b in the tangential direction of the circle centered on the central axis C, and the chip breaker piece 9 is placed around the central axis C in FIG. As shown in the above, the breaker piece is rotationally driven in the rotation direction T.

Further, the coolant that has been rotationally driven by the chip breaker piece 9 is discharged from the first coolant discharge hole 11b and flows into the second coolant discharge hole 11c, and further, the insert mounting seat 4 of the second coolant discharge hole 11c. It is discharged from the opening in the bottom surface 4a and is ejected from the opening 10a in the rake face 6b of the cutting insert 6 through the insertion holes 10 formed in the sheet member 7 and the cutting insert 6.

In the cutting tool with a tip breaker piece configured as described above, the axial tip breaker piece 9 having the tip portion 9a protruding from the opening 10a of the insertion hole 10 on the rake face 6b of the cutting insert 6 is the central axis C. Since the circuit breaker piece can be rotationally driven in the rotation direction T, the chip breaker piece 9 is driven to rotate and is brought into contact with the chips generated by the insert cutting blade 6a, so that one part of the tip portion 9a is chipped. It is possible to prevent the chip breaker piece 9 from being worn out by avoiding continuous contact with the chip breaker piece 9.

Further, since the resistance due to the scraping of chips can be released by the rotation of the chip breaker piece 9, it is possible to suppress the cutting resistance from becoming larger than necessary, and the large cutting resistance causes chatter vibration in the tool body 1. Therefore, it is possible to prevent deterioration of the machined surface accuracy and the machined surface roughness of the work material.

The tip breaker piece 9 is inserted into the insertion hole 10 so that the tip portion 9a thus protrudes from the opening 10a formed in the rake face 6b of the insert cutting edge 6a of the cutting insert 6. It is rotationally driven around the central axis C extending in the direction intersecting the rake face 6b.

Therefore, even if a slightly elongated chip is generated when the soft work material is cut by the insert cutting edge 6a, the tip portion 9a of the chip breaker piece 9 is projected in the outflow direction of the chip and is rotationally driven. , It is possible to control the outflow direction of the chips by giving an appropriate frictional resistance to the chips. Therefore, it is possible to prevent a situation in which such elongated chips are entangled with the tool body 1 and the cutting process is interrupted, so that smooth and stable cutting process can be performed.

Further, in the present embodiment, a coolant hole 11 for supplying coolant is formed from the cutting edge portion 3 at the tip of the tool body 1 to the sheet member 7 and the cutting insert 6, and the coolant hole 11 is inserted. The tip breaker piece 9 is rotationally driven by the coolant supplied to the coolant hole 11, which is opened so as to coincide with the opening 10a in the rake face 6b of the hole 10.

Therefore, it is not necessary to provide a relatively large space for accommodating such a rotation drive mechanism at the tip of the tool body 1, as in the case where the chip breaker piece 9 is rotationally driven by a rotation drive mechanism such as a motor. Therefore, it is possible to prevent a situation in which chatter vibration occurs due to the strength and rigidity of the tool body 1 being impaired by such a large space.

Moreover, by matching the opening of the coolant hole 11 on the rake face 6b of the cutting insert 6 with the opening 10a on the rake face 6b of the insertion hole 10 in this way, the tip portion 9a of the tip breaker piece 9 is cooled by the coolant. , Lubrication can be achieved, and wear of the tip portion 9a of the chip breaker piece 9 can be prevented more reliably. Further, by ejecting the coolant from the opening 10a of the insertion hole 10 from which the tip 9a of the tip breaker piece 9 protrudes, the outflow direction of the chips in contact with the tip 9a can be controlled more stably. It becomes.

Further, in the present embodiment, in order to rotationally drive the chip breaker piece 9 with the coolant in this way, the rotating member 9D arranged at the rear end portion of the chip breaker piece 9 projects to the outer peripheral side in the radial direction with respect to the central axis C. The rotary blade 9g is provided, and the coolant supply hole 11a of the coolant hole 11 is communicated with the large diameter portion 10b of the insertion hole 10 so that the coolant is injected into the rotary blade 9g.

Therefore, for example, by changing the supply pressure and the supply amount of the coolant according to the outflow speed of chips due to cutting conditions and the like, the rotation speed of the chip breaker piece 9 can be adjusted to process the chips under the optimum conditions. .. Moreover, in the present embodiment, the rotary blade 9g is twisted around the central axis C so as to be toward the tip side of the chip breaker piece 9 in the central axis C direction and toward the coolant supply direction F side. A discharge pressure toward the tip end side of the chip breaker piece 9 acts on the coolant discharged from the coolant discharge hole 11b through the second coolant discharge hole 11c, and the coolant is ejected from the opening 10a of the insertion hole 10. The coolant ejection pressure can also be increased.

By the way, the tip of the chip breaker piece 9 of the present embodiment is formed in a convex hemispherical shape as described above, and the chip outflow direction is controlled by contacting with the chips. Like the tip breaker piece 9 of the first modification shown in 11, the central axis line is attached to the tip portion 9a of the breaker piece main body 9A protruding from the opening 10a of the insertion hole 10 in the rake face 6b of the cutting insert 6. A plurality of chip pockets 9h extending to C are formed at intervals in the circumferential direction, and at the intersecting ridge line portion between the wall surface of these chip pockets 9h facing the breaker piece rotation direction T and the surface of the tip portion 9a of the breaker piece body 9A. , A tip breaker piece cutting edge 9i such as a ball end mill may be formed.

Further, as in the tip breaker piece 9 of the second modified example shown in FIG. 12, the tip portion 9a of the breaker piece main body 9A protruding from the opening 10a of the insertion hole 10 on the rake face 6b of the cutting insert 6 is formed into a multi-stage cone. A chip breaker that is formed in a trapezoidal shape to form chip pockets 9h, and is bent in multiple stages at the intersection ridge between the wall surface of these chip pockets 9h facing the breaker piece rotation direction T and the surface of the tip portion 9a of the breaker piece body 9A. The piece cutting edge 9i may be formed.

Further, as in the tip breaker piece 9 of the third modified example shown in FIG. 13, the tip portion 9a of the breaker piece main body 9A protruding from the opening 10a of the insertion hole 10 on the rake face 6b of the cutting insert 6 is formed into a columnar shape. Formed to form chip pockets 9h, such as a square end mill or a radius end mill, at the intersecting ridge between the wall surface of these chip pockets 9h facing the breaker piece rotation direction T and the surface of the tip portion 9a of the breaker piece body 9A. The tip breaker piece cutting edge 9i may be formed.

According to a cutting tool with a tip breaker piece provided with the tip breaker piece 9 of the first to third modified examples, the chips generated by the insert cutting edge 6a of the cutting insert 6 are raked into the rake face of the cutting insert 6. When the tip breaker piece 9 projecting from the opening 10a of the insertion hole 10 in 6b comes into contact with the tip portion 9a, it can be divided by the tip breaker piece cutting blade 9i, so that when cutting a soft work material. Even if the chips that are slightly stretched are generated, it can be more reliably prevented from being entangled with the tool body 1. Therefore, smoother and more stable cutting can be performed.

Next, FIGS. 14 and 15 show the second embodiment of the present invention, and the same reference numerals are given to the parts common to the first embodiment shown in FIGS. 1 to 10. The explanation is omitted. Further, the coolant hole 11 in the second embodiment is the same as the coolant hole 11 in the first embodiment shown in FIG.

In the cutting tool with a chip breaker piece of the first embodiment, the chip breaker piece 9 only rotates around the central axis C in the direction of rotation T of the breaker piece, whereas the chip breaker piece of the second embodiment only rotates. The cutting tool with a tip is characterized in that the chip breaker piece 9 rotates around the central axis C in the direction of rotation T of the breaker piece, and in addition, the tip breaker piece 9 can move forward and backward with a constant stroke in the direction of the central axis C.

Here, in the present embodiment, in the first embodiment, the outer peripheral surfaces of both ends of the rotating member 9D arranged in the large diameter portion 10b of the insertion hole 10 in the central axis C direction and the inner peripheral surface of the large diameter portion 10b. Of the annular bearings 12 having a square cross section interposed between the bearings, the bearing 12 on the rear end side in the central axis C direction is further connected to the first bearing 12A on the front end side in the central axis C direction and the rear end side. It is formed by being divided in the central axis C direction by the second bearing 12B. Of these, the inner diameter of the tip of the first bearing 12A on the tip side is set to be extremely slightly larger than the outer diameter of the rear end of the rotating member 9D, and the tip breaker piece 9 is rotatably supported.

The rear end of the first bearing 12A has an inner diameter larger than that of the tip, and the cross section along the central axis C is formed in an L shape as shown in FIG. Further, as shown in FIG. 14, the second bearing 12B has an L-shaped cross section in which the outer diameter of the tip portion is smaller than the outer diameter of the rear end portion, and the outer diameter of the rear end portion is the first. The outer diameter of the bearing 12A is equal to that of the first bearing 12A, and the rear end portion is attached to the inner peripheral surface of the large diameter portion 10b of the insertion hole 10 by tightening or the like, and the outer diameter of the tip portion is the first bearing 12A. It is sized so that it can be fitted into the inner circumference of the rear end.

Furthermore, the amount of protrusion in the central axis C direction from the rear end of the tip of the second bearing 12B is smaller than the amount of protrusion in the central axis C direction from the tip of the rear end of the first bearing 12A. As a result, with the tip of the second bearing 12B fitted into the inner peripheral portion of the rear end of the first bearing 12A, the rear end surface 12a of the tip of the first bearing 12A and A gap is provided in the direction of the central axis C from the tip surface 12b of the tip of the second bearing 12B.

Then, the rear end surface 12a of the tip end portion of the first bearing 12A and the tip end surface 12b of the tip end portion of the second bearing 12B are uneven in the central axis C direction toward the circumferential direction around the central axis C. It is used as a guide surface in the embodiment. In the present embodiment, the rear end surface 12a and the front end surface 12b, which are the guide surfaces, have a shape that gently undulates so as to draw an uneven curved surface having the same dimensions and shape as the circumferential direction. The convex curved surface portion of the tip surface 12b is located on the rear end side of the concave curved surface portion of 12a in the central axis C direction, and the interval in the central axis C direction is constant in the circumferential direction.

On the other hand, in the present embodiment, in the chip breaker piece 9, the rear end portion of the shaft member 9C protruding from the rear end surface of the rotating member 9D is extended longer than that of the first embodiment, and the protruding rear end portion is extended. Is fitted with a columnar pin 9E in the radial direction with respect to the central axis C. The diameter of the pin 9E is slightly smaller than the distance between the rear end surface 12a and the tip surface 12b of the first and second bearings 12A and 12B in the central axis C direction, and both ends of the pin 9E are formed. The chip breaker piece 9 is supported so as to be rotationally driveable around the central axis C while being in sliding contact with the rear end surface 12a and the front end surface 12b.

The rotating member 9D of the chip breaker piece 9 and both ends of the rotating blade 9g in the central axis C direction, the bearing 12 attached to the front end side of the large diameter portion 10b of the insertion hole 10, and the rear end side were attached. Between the first bearing 12A and the first and second bearings 12A and 12B having a concavo-convex curved surface, advancing and retreating with a stroke from the bottom of the concave portion of the concave portion to the protruding end of the convex portion There is an acceptable interval. Further, in the present embodiment, the support member 14 is not attached to the inner peripheral portion of the support member holder 14b.

In such a cutting tool with a tip breaker piece of the second embodiment, as the tip breaker piece 9 rotates around the central axis C, the pins 9E are the rear end faces of the first and second bearings 12A and 12B. By sliding the tip surface 12a and the tip surface 12b, as described above, the chip breaker piece 9 has a concavo-convex curved surface with a constant stroke from the bottom of the recess to the tip of the convex portion of the rear end surface 12a and the tip surface 12b. It is possible to move forward and backward in the direction of the central axis C.

Therefore, in addition to the resistance due to the contact of the tip breaker piece 9 with the tip 9a, the tip of the chip when the tip breaker piece 9 advances in the central axis C direction and protrudes from the opening 10a of the insertion hole 10. The striking force of the portion 9a is also given. Therefore, according to the present embodiment, it is possible to divide the chips and control the outflow direction by the impact caused by the striking force.

Further, in the present embodiment, in order to enable the chip breaker piece 9 to advance and retreat in the central axis C direction in this way, a pin 9E projecting to the outer peripheral side in the radial direction with respect to the central axis C is provided at the rear end of the chip breaker piece 9. The rear end surfaces 12a and the tip surfaces of the first and second bearings 12A and 12B, which are the peripheral surfaces of the inner peripheral portion of the insertion hole 10 in the cutting edge portion 3 of the tip portion of the tool body 1 facing the central axis C direction. 12b is a guide surface that is uneven in the central axis C direction toward the circumferential direction.

Therefore, moving the chip breaker piece 9 in the central axis C direction with a constant stroke does not require a mechanism such as a cam or a cylinder device, and moves in the central axis C direction as the chip breaker piece 9 rotates. Since it can be advanced and retreated, it is possible to avoid an unnecessarily large number of parts and driving means. Moreover, the advance / retreat stroke of the chip breaker piece 9 can be changed by replacing the first and second bearings 12A and 12B with bearings having different uneven curved surfaces of the rear end surface 12a and the front end surface 12b.

1 Tool body 2 Shank part 3 Cutting edge part (tip of tool body 1)
4 Insert mounting seat 5 Clamp member 6 Cutting insert 6a Insert cutting edge 6b Scooping surface 7 Seat member 8 Clamp screw 9 Chip breaker piece 9a Tip breaker piece 9 tip 9g Rotating blade 9i Chip breaker piece cutting edge 9E pin 10 Insert hole 10a Opening of insertion hole 10 11 Coolant hole 12 Bearing 12A First bearing 12B Second bearing 12a Rear end surface (guide surface) of the first bearing 12A
12b Tip surface (guide surface) of the second bearing 12B
C Central axis of chip breaker piece 9 T Breaker piece rotation direction F Coolant supply direction

Claims (6)

A cutting insert having an insert cutting edge formed at the intersection ridge between the rake surface and the flank on the insert mounting seat formed at the tip of the tool body attaches / detaches the rake surface toward the outer peripheral side of the tool body. Can be installed,
From the tip of the tool body to the cutting insert, an insertion hole into which the cylindrical shaft-shaped tip breaker piece is inserted is formed and opens to the rake face.
The chip breaker piece is inserted into the insertion hole by projecting the tip of the chip breaker piece from the opening of the insertion hole on the rake face, and can be rotationally driven around the central axis of the chip breaker piece. A cutting tool with a replaceable cutting edge with a tip breaker piece, which is characterized by being supported. A coolant hole for supplying coolant is formed from the tip end portion of the tool body to the cutting insert, and the coolant hole is opened corresponding to the opening on the rake face of the insertion hole.
The cutting tool with a tip breaker piece and a replaceable cutting edge according to claim 1, wherein the tip breaker piece is rotationally driven by a coolant supplied to the coolant hole. At the rear end of the chip breaker piece, a rotary vane projecting radially to the outer peripheral side with respect to the central axis is provided.
The cutting edge exchangeable cutting with a tip breaker piece according to claim 2, wherein the tip breaker piece is rotationally driven by the coolant hole communicating with the insertion hole and injecting coolant onto the rotary blade. tool. The cutting edge exchangeable cutting with a tip breaker piece according to any one of claims 1 to 3, wherein the tip breaker piece can move forward and backward with a constant stroke in the central axis direction. tool. The rear end of the chip breaker piece is provided with a pin that projects radially outward with respect to the central axis, and the circumference of the inner peripheral portion of the insertion hole at the tip of the tool body that faces the central axis. The surface is provided with a guide surface that is uneven in the central axis direction toward the circumferential direction, and the tip breaker piece is constant in the central axis direction by rotating while the pin is in sliding contact with the guide surface. The cutting tool with a tip breaker piece and a replaceable cutting edge according to claim 4, wherein the cutting tool can move forward and backward with a stroke. Any one of claims 1 to 5, wherein a tip breaker piece cutting edge is provided at the tip of the tip breaker piece protruding from the opening of the insertion hole on the rake face. Cutting tool with replaceable cutting edge with tip breaker piece as described in the section.

Images