JP4479521B2 - Cutting insert clamping mechanism - Google Patents

Description

  The present invention relates to a clamping mechanism for a cutting insert for detachably attaching a cutting insert to an insert mounting seat of a holder in, for example, an insert detachable tool used for grooving or parting off a work material.

  As a clamping mechanism of a cutting insert applied to an insert detachable tool used for such grooving or parting-off processing, a pair of jaws that open to the tip side is formed elastically deformable at the tip of the holder. Of the pair of jaw portions, one jaw portion is provided with a pressing portion having a pressing surface, and the other jaw portion is provided with a pedestal having a pedestal surface, and the pressing surface and the seating surface face each other. The pressing portion and the pedestal constitute an insert mounting seat, a cutting insert is inserted into the insert mounting seat, and the pair of jaws are brought close to the abutting direction. It is known that a pressing surface and a pedestal surface formed on a jaw are brought into contact with a pressed surface and a seating surface formed on a cutting insert, pressed, and clamped.

  In general, in order to clamp the cutting insert by elastically deforming the jaw portion, for example, as described in Patent Document 1 or Patent Document 2, a clamp screw inserted into one jaw portion is screwed into the other jaw portion. Therefore, a means is adopted in which the one jaw portion is bent toward the other jaw portion. In other words, the base part of the jaw part is used as a fulcrum, the clamp screw is used as a force point, the pressing surface of the pressing part formed on one jaw part is used as the action point, and one of the jaw parts is elastically deformed toward the other jaw part. In other words, the cutting insert is clamped by bringing the pressing portion closer to the pedestal.

  Here, the above-mentioned insert mounting seat extends from one end in the width direction of the holder to the tool tip, that is, from a position greatly deviated from the axis of the holder, with a width narrower than the width of the holder, The cutting insert is clamped at a position displaced from the axis of the holder. In general, the clamp screw is provided near the central portion in the width direction of the wide holder, that is, in the vicinity of the axis of the holder along the direction in which the jaw portion is elastically deformed in order to stably hold the screw. ing.

The insert detachable tool having the clamp mechanism described above is a workpiece that is fixed by sandwiching the cutting insert with an insert mounting seat formed at the tip of the holder, supported by a machine tool such as a lathe or a machining center, and rotated at a high speed. The outer surface and the end surface of the workpiece are cut by the cutting blade of the cutting insert by being moved relative to the workpiece while the cutting insert is pressed against the workpiece.

  In the above clamping mechanism, the pressing part (action point) formed on one jaw part is located at the position where the clamp screw (force point) for elastically deforming the jaw part and the base part (fulcrum) of the jaw part are located. When the clamp screw is further screwed in after the pair of jaws are brought close to each other and the pressing surface of the pressing portion comes into contact with the pressed surface of the cutting insert, A bending moment is generated in the jaw, and the pressing surface of the pressing portion comes into contact with an inclination with respect to the contact direction, or the center line of the pressing surface of the pressing portion deviates from the center line of the pressed surface of the cutting insert. Sometimes touched.

  In the insert detachable tool in which the cutting insert is attached in the above state, the contact between the pressing surface of the pressing portion and the pressed surface of the cutting insert becomes insufficient, and the cutting insert cannot be firmly fixed, and cutting is performed. There was a problem that chattering occurred during processing, the processing accuracy of the tool was remarkably lowered, and the cutting insert was damaged or dropped due to chattering.

  Furthermore, a large bending moment is generated in one jaw, and the contact portion between the pressing surface of the pressing portion and the pressed surface of the cutting insert is the base surface of the pedestal formed on the other jaw and the seating of the cutting insert. When the cutting insert is positioned on the outer side in the width direction with respect to the contact portion with the surface, there is a problem that the cutting insert is inclined by strongly pressing the cutting insert with the pressing surface. When cutting is performed with the cutting insert tilted, the cutting angle and clearance angle of the cutting blade will be distorted, the machining accuracy will deteriorate, and the cutting insert will be overloaded and the cutting insert will be damaged. There was a problem.

In order to solve these problems, in Patent Document 2, when the cutting insert is placed on the pedestal provided on the other jaw portion on the pressing surface of the pressing portion provided on one jaw portion, the cutting insert is provided. There has been proposed a clamping mechanism for a cutting insert provided with a protrusion that protrudes toward a center line along the longitudinal direction of the cutting insert.
In the clamp mechanism having the above configuration, a bending moment is generated in one jaw portion, and the pressing surface of the pressing portion provided on the one jaw portion is inclined with respect to the pressed surface of the cutting insert, Even when the center line of the surface and the center line of the pressed surface are shifted and approached, the protrusion provided on the pressing surface of the pressing portion can contact the vicinity of the center line of the cutting insert and press the cutting insert, The cutting insert can be attached stably.
JP 2002-337909 A JP 2001-62609 A

  However, in the clamp mechanism proposed in Patent Document 2, the portion that presses the pressed surface of the cutting insert is only one point of the protrusion, and the insert detachable tool to which the clamp mechanism is applied is laterally fed. That is, when it is fed along a surface perpendicular to the contact direction, this feed force cannot be sufficiently received, and the cutting insert follows the pedestal surface of the pedestal formed on the other jaw. There was a problem of moving. In this case, the machining accuracy of the insert detachable tool is remarkably deteriorated, and the cutting insert is damaged or dropped.

  The present invention has been made in view of the above situation, and the pressing surface of the pressing portion formed on one jaw portion is inclined with respect to the abutting direction, or the pressing surface of the pressing surface is Even when the center line and the center line of the pressed surface are out of contact with each other, the cutting insert can be firmly fixed, and even when the insert detachable tool to which this clamping mechanism is applied is laterally fed, It aims at providing the clamp mechanism of the cutting insert which can prevent the movement of a cutting insert.

In order to solve the above-described problems, the present invention is configured to abut an insert mounting seat formed at a tip portion of a holder, which has a pressing surface and a pedestal surface facing each other, on the pressing surface and the pedestal surface, respectively. A clamping mechanism of a cutting insert that clamps by inserting and sandwiching a cutting insert having a pressed surface and a seating surface, and one jaw portion and the other jaw portion are provided at a tip portion of the holder. A pair of jaws is formed, the one jaw is provided with a pressing part on which the pressing surface is formed, and the other jaw is provided with a base on which the pedestal surface is formed. In the cross section perpendicular to the longitudinal direction of the insert, the seating surface and the pedestal surface of the insert are supported at a pair of support positions spaced in the width direction, and the pressing surface and the pressed surface are wide. Spacing in the direction While being pressed by the pair of pressing position digits, disposed between said pair of pressing positions of the pair of support positions in the width direction, additionally, at least one of said pressing surface and the pedestal surface, the object At least one of the pressing surface and the seating surface is provided with a pair of inclined planes, one of which is inclined so as to form a convex V shape in the cross section perpendicular to the longitudinal direction of the insert, and the other is a It is characterized by being made into the concave V shape provided with a pair of convex curved surface with the roundness which becomes convex toward the inclination plane side .

  In the cutting insert clamping mechanism according to the present invention, in the cross section perpendicular to the longitudinal direction of the insert, the pedestal surface provided on the other jaw and the seating surface of the cutting insert are supported at a pair of support positions. Since the pressing surface provided on the part and the pressed surface of the cutting insert are pressed at a pair of pressing positions, the insert detachable tool to which this clamping mechanism is applied is laterally fed along a surface perpendicular to the contact direction. Even in this case, the feed force can be received at two points of one pressing position and one support position, and the cutting insert can be prevented from moving due to the feed force. Therefore, even when the insert detachable tool is laterally fed along a surface perpendicular to the contact direction, it is possible to prevent deterioration of the machining accuracy of the insert detachable tool and to prevent the cutting insert from being damaged or dropped off. it can.

  Further, since the pair of pressing positions are arranged between the pair of supporting positions in the width direction in a cross section perpendicular to the longitudinal direction of the insert, a bending moment is generated in one jaw portion, and the pressing portion is Even if the approach is inclined with respect to the pedestal, or the center line of the pressing portion and the center line of the pedestal are shifted and approached, the pressed surface of the cutting insert and the pressing surface of the pressing portion are paired. The pair of pressing positions are arranged between a pair of supporting positions where the seating surface and the pedestal surface are in contact with each other, and the cutting insert can be more stably fixed. Even when the pressed surface is pressed by the pressing portion, the cutting insert can be prevented from being inclined. Therefore, the cutting angle and clearance angle of the cutting blade of the cutting insert do not change, the processing accuracy of the insert detachable tool can be greatly improved, and an excessive load is prevented from being applied to the cutting insert. It is possible to prevent breakage or dropout of the insert.

  Further, in the cross section perpendicular to the longitudinal direction of the insert, the pair of support positions is the width of the surface of the base surface and the seating surface that are in contact with each other at the support positions and having a small size in the width direction. Comparison of the width direction among the portions involved in the clamping on the pedestal surface and the seating surface by being positioned in the range of W / 10 to W / 3 with respect to the dimension W in the width direction from both ends in the direction. The cutting insert can be supported by the outer portion of the target, and the clamping of the cutting insert can be more stable. That is, if the pair of support positions are arranged on the inner side of the above range, the cutting insert may be inclined in the cross section when a large load is applied during cutting. If it is located outside the above range, there is a possibility that the clamping force concentrates on the outer end corner of the surface having a small dimension in the width direction, causing a defect or deformation.

  Further, in the cross section perpendicular to the longitudinal direction of the insert, the pair of pressing positions is the surface of the pressing surface that is in contact with each other at these pressing positions and the surface to be pressed, which is not large in the width direction. A pair of pressing positions of the pressing surface and the pressed surface is set to the pair of pressing surfaces by being positioned in the range of W / 8 to 4W / 9 with respect to the width dimension W from both ends in the width direction. The insert can be reliably arranged on the inner side in the width direction of the support position, and the insert can be fixed more stably. In addition, since the pair of pressing positions does not concentrate at one point near the center in the width direction of the insert, the feed force when the insert detachable tool to which the clamp mechanism of the insert is applied is laterally fed is It can be reliably received at the two points of the pressing position and one of the supporting positions.

  Further, at least one of the pressing surface and the pedestal surface and at least one of the pressed surface and the seating surface are convex V-shaped in a cross section perpendicular to the longitudinal direction of the insert. By forming a pair of inclined planes that incline so as to form a shape, and the other is a concave V-shape having a pair of convex curved surfaces that are rounded toward the inclined plane side. Position control in the width direction of the pair of pressing positions and the pair of support positions can be easily performed.

  Further, the pair of convex curved surfaces forming the concave V shape contact each other because the convex V shape is a pair of flat inclined planes. In the clamping mechanism, a pair of convex curved surfaces are microscopically formed in the pressing position and the supporting position, respectively, because the convex curved surface and the inclined plane are brought into contact with each other. Since it is made to contact | abut in the state close | similar to a surface contact along the tangent plane parallel to this inclination plane, it becomes possible to ensure high attachment stability. Therefore, according to the clamping mechanism of the cutting insert having the above-described configuration, the cutting insert can be stably and highly accurately and high without requiring strict molding accuracy on the pressing surface, the pedestal surface, the pressed surface, and the seating surface. With the mounting rigidity, it can be clamped to the insert mounting seat of the holder, which makes it possible to achieve smooth and accurate grooving and parting off

  In addition, in the cross section perpendicular to the longitudinal direction of the insert, the pair of inclined planes may be inclined in a direction intersecting at an intersecting angle of 110 ° to 160 °, or the protrusions at the pair of supporting positions and the pair of pressing positions. The curvature radius of the curved surface is determined between the pedestal surface and the seating surface where the pair of inclined flat surfaces and the pair of convex curved surfaces come into contact with each other at the supporting position and the pressing position, and among the pressing surface and the pressed surface. A pair of inclined planes can be obtained by adopting a range of 0.4 × U to 4.0 × U with respect to the dimension U in the width direction of the surface having a small dimension in the width direction, or adopting them together. Further, it is possible to more reliably suppress the variation of the contact position due to the molding error of the pair of convex curved surfaces.

  That is, if the intersection angle between the pair of inclined planes is smaller than the above range, or if the curvature radius of the convex curved surface is larger than the above range and the convex curved surface is close to the plane, there is an error in the intersection angle or the curvature radius. If this occurs, the contact position may vary greatly. Further, when the crossing angle is larger than the above range and the pair of inclined planes become nearly flat, stability when a load is generated in the width direction during cutting is impaired, and the curvature radius of the convex curved surface is larger than the above range. If it is smaller, the contact with the inclined plane becomes close to the line contact, and there is a possibility that the stability due to the surface contact as described above cannot be achieved.

  Thus, according to the present invention, the pressing surface of the pressing portion formed on one jaw portion is in contact with an inclination with respect to the contact direction, or the center line of the pressing surface and the pressed surface The cutting insert can be firmly fixed even when it is in contact with the center line, and the cutting insert can be prevented from moving even when the insert detachable tool to which this clamping mechanism is applied is laterally fed. A clamping mechanism for the cutting insert can be provided.

A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cutting insert and a holder of an insert detachable tool to which the clamp mechanism according to the first embodiment is applied, FIGS. 2 to 4 show a holder with a cutting insert, and FIG. 5 shows a cutting insert.
In this insert detachable tool, the holder 1 is formed of a steel material or the like, and as shown in FIGS. 2 and 3, a square columnar shank portion 2 extending along the axis L on the rear end side (right side in FIGS. 2 and 3). 2 and the front end portion (the left side portion in FIGS. 2 and 3) slightly protrudes laterally from one side surface 2A of the shank portion 2 as shown in FIG. As shown in FIG. 3, the head portion 3 protrudes so that the upper portion rises from the upper surface 2 </ b> B of the shank portion 2.

  The head portion 3 is formed with a slit 3A along the extended surface of the upper surface 2B of the shank portion 2 from the front end side. The upper jaw portion 3B above the slit 3A is the lower lower jaw portion 3C. The thickness in the direction perpendicular to the extended surface is made thinner as shown in FIG. In addition, the cross-sectional area of the connection portion 3D between the upper jaw 3B and the shank portion 2 defined by the slit 3A is also smaller than the cross-sectional area of the connection portion between the lower jaw 3C and the shank portion 2, and the upper jaw 3B. Is elastically deformable so as to bend toward the lower jaw 3C side with this connecting portion 3D as a fulcrum.

  A pedestal 4 is formed at the distal end of one side 2A of the shank 2 of the lower jaw 3C so that the distal end extends in a rectangular flat plate shape parallel to the axis L of the shank 2, and the upper surface of the pedestal 4 is The contact surface (base surface 5) is formed so as to extend from the tip of the lower jaw 3C to the middle of the slit 3A in the longitudinal direction of the holder 1. The pedestal surface 5 is formed in a convex V shape by a pair of inclined planes 5A and 5B that approach each other in the cross section perpendicular to the axis L, and the crossing angle of the pair of inclined planes, that is, The angle α formed by the convex V-shape of the pedestal surface 5 is 160 °.

  On the other hand, the tip portion on the side surface 2A side of the shank portion 2 of the upper jaw portion 3B has a triangular plate shape having a hypotenuse that goes downward as it goes to the tip end side along the pedestal 4 provided on the lower jaw portion 3C. The formed pressing portion 6 is provided, the tip of which is retracted from the tip of the lower jaw portion 3C, and the surface of the pressing portion 6 facing the pedestal 4 is the contact surface (pressing surface 7). The lower jaw part 3C extends from the central part in the longitudinal direction of the pedestal surface 5 to the front end side slightly from the rear end of the pedestal face 5 from the front end side. The pressing surface 7 formed on the pressing portion 6 is formed in a convex V shape by a pair of inclined planes 7A and 7B that approach each other as it goes downward in a cross section orthogonal to the axis L, and the pair of inclined planes 7A, 7B, that is, the angle β formed by the convex V-shape of the pressing surface 7 is 110 °, and is smaller than the angle α formed by the convex V-shape of the pedestal surface 5 formed on the pedestal 4.

  Thus, the pedestal surface 5 formed on the pedestal 4 and the pressing surface 7 formed on the pressing portion 6 face each other, and the convex V formed by a cross section orthogonal to the axis L of the pedestal surface 5 and the pressing surface 7 is formed. The bisectors of the characters are arranged so as to coincide with each other, and the pressing portion 6 and the pedestal 5 constitute an insert mounting seat 8. Therefore, in the present embodiment, the upper jaw portion 3B is one jaw portion and the lower jaw portion 3C is the other jaw portion, and the pressing surface 7 of the pressing portion 6 and the pedestal surface 5 of the pedestal 4 face each other. The direction perpendicular to the surface to be touched is the contact direction, and the upper jaw portion 3B can be elastically deformed in this contact direction.

  The cutting insert 11 according to the embodiment of the present invention attached to the insert mounting seat 8 having the above-described configuration is made of a hard material such as cemented carbide, and the outer shape of the cutting insert 11 and the insert body 12 formed in a substantially square bar shape. And a blade portion 16. The insert body 12 has a constant width in the longitudinal direction, and a convex portion 13 protruding upward is provided at the center in the longitudinal direction of the insert body 12.

  And the upper surface of the convex part 13 is made into the to-be-pressed surface 14, and as shown in FIG. 5, this pressed surface 14 is a pair of convexes which mutually approach so that it may go down toward the inner side of the width direction of the insert main body 12. The curved surfaces 14A and 14B are provided, and the pressed surface 14 is formed by the pair of convex curved surfaces 14A and 14B so as to form a substantially concave V shape in a cross section orthogonal to the longitudinal direction of the insert body 12. Yes. Further, the pair of convex curved surfaces 14A and 14B have an arc shape in a cross section orthogonal to the longitudinal direction of the insert body 12, and the concave V-shaped valley bottom portion where the pair of convex curved surfaces 14A and 14B intersect is The concave curved surface has a concave arc shape that smoothly contacts the pair of convex curved surfaces 14A and 14B.

  Further, the lower surface of the insert body 12 is a seating surface 15, and the seating surface 15 has a pair of convex curved surfaces 15 </ b> A that approach each other so as to go upward as they go inward in the width direction of the insert body 12, as shown in FIG. 5. 15B is provided, and by this pair of convex curved surfaces 15A and 15B, the seating surface 15 has a substantially concave V-shape in a cross section orthogonal to the longitudinal direction of the insert body 12. That is, a concave V-shape that is symmetrical to the concave V-shape formed by the pressed surface 14 formed on the upper surface of the convex portion 13 is formed.

  Cutting blade portions 16 are arranged on the upper surface sides of both ends in the longitudinal direction of the insert body 12, and cutting blades 17 extending in a direction perpendicular to the longitudinal direction of the insert body 12 are formed on the upper surface end portions of the cutting blade portions 16, respectively. The surfaces that are continuous with these cutting edges 17 and face one end and the other end in the longitudinal direction are flank faces 18 of the cutting edges 17, and as shown in FIG. It is inclined so that it may approach the center part side of the longitudinal direction of the insert main body 12 as it goes to, and the positive clearance angle is given.

  Further, a surface extending toward the upper surface side of the cutting insert 11 so as to be continuous with the cutting edge 17 is a rake face 19, and the rake face 19 is viewed from the top as shown in FIG. It is formed in an isosceles trapezoidal shape so as to be wider than the width of the insert body 12 and is arranged so as to be shorter than the upper surface of the convex portion 13 in the longitudinal direction. That is, the cutting insert 11 is a dog bone type insert formed so as to be symmetric with respect to the central portion in the longitudinal direction.

  Here, as a clamping means of the insert mounting seat 8, a clamp screw 22 inserted from above into the head portion 3 at the tip of the holder 1 is provided. The clamp screw 22 extends beyond the slit 3 </ b> A to the lower jaw portion 3 </ b> C. And a head that is larger in diameter than the male screw and accommodated in the upper jaw portion 3B. A general-purpose work tool such as a wrench is provided on the end surface of the head. An engagement hole is formed to engage the.

  On the other hand, a mounting hole 23 to which the clamp screw 22 is attached is formed in the head portion 3 in the vicinity of the axis L of the shank portion 2 so as to be along the contact direction. 22 is formed of a screw hole 24 on the lower jaw part 3C side to which the male screw part is screwed, and an accommodation hole 25 on the upper jaw part 3B side that is formed coaxially with the screw hole 24 and accommodates the head. ing. The accommodation hole 25 passes through the upper jaw portion 3B from the slit 3A and is opened on the upper surface 3E of the head portion 3 (upper surface of the upper jaw portion 3B) parallel to the slit 3A. Engagement holes provided in the end surface are exposed to the upper surface 3 </ b> E side of the head portion 3 through the accommodation holes 25.

  By screwing the male screw portion of the clamp screw 22 into the screw hole 24 so as to advance toward the lower surface 3F side of the head portion 3, the upper jaw portion 3B is elastically deformed by the head portion of the clamp screw 22 so as to approach the lower jaw portion 3C. Accordingly, the pressing surface 7 of the pressing portion 6 is moved so as to approach the pedestal surface 5 of the pedestal 4, and the seating surface 15 and the pedestal surface 5 of the cutting insert 11 are supported at a pair of support positions SS ′. Then, the pressing surface 7 of the pressing portion 6 and the pressed surface 14 on the upper surface of the convex portion 13 of the cutting insert 11 are pressed at a pair of pressing positions PP ′.

  Further, as shown in FIG. 6, the angle β formed by the convex V-shape of the pressing surface 7 formed on the pressing portion 6 is smaller than the angle α formed by the convex V-shaped of the pedestal surface 5 formed on the pedestal 4. In addition, since the concave V-shape having the same shape is formed on the pressed surface 14 and the seating surface 15 of the cutting insert 11, the pressing surface 7 in the width direction in the cross section perpendicular to the longitudinal direction of the cutting insert 11. A pair of pressing positions PP ′ between the pressing surface 14 and the pressed surface 14 is positioned between a pair of supporting positions SS ′ between the seating surface 15 and the pedestal surface 5.

  Note that the radius of the arc formed by the cross section of the convex curved surface is the width direction of the abutting surfaces (pressing surface 7 and pedestal surface 5) and the abutting surfaces (pressed surface 14 and seating surface 15) that abut each other. The range of 0.4 to 4.0 times the width of the non-small surface. Specifically, in this embodiment, as shown in FIG. 6, the width U of the pressed surface 14 and the seating surface 15 on the cutting insert 11 side is the width of the pressing surface 7 of the pressing portion 6 and the base surface 5 of the base. The radius of curvature of the convex curved surface is in the range of 0.4 × U to 4.0 × U with respect to the width dimension U of the pressed surface 14 and the seating surface 15 of the cutting insert 11. Has been.

  Further, the pair of support positions SS ′ is a pedestal surface on which the pair of convex curved surfaces 15A, 15B forming the seating surface 15 and the pair of inclined planes 5A, 5B forming the pedestal surface 5 abut on each other. 5 and the seating surface 15 are positioned in the range of 1/10 to 1/3 of the dimension in the width direction on the inner side from both ends in the width direction of the surface not having the dimension in the width direction. Specifically, in this embodiment, as described above, the width dimension U of the seating surface 15 on the cutting insert 11 side is made larger than the width dimension W of the pedestal surface 5 on the insert mounting seat 8 side. The dimension W is reduced, and the support position SS ′ is positioned inward from both ends in the width direction of the pedestal surface 5 within a range from the position W / 10 to the position W / 3.

  Further, the pair of pressing positions PP ′ is a pressing in which the pair of convex curved surfaces 14A and 14B forming the pressed surface 14 and the pair of inclined flat surfaces 7A and 7B forming the pressing surface 7 are in contact with each other at these pressing positions PP ′. Of the surface 7 and the pressed surface 14, the surface not having a large dimension in the width direction is positioned inward from both ends in the width direction within a range of 1/8 to 4/9 of the dimension in the width direction. Yes. Specifically, in the present embodiment, as described above, the width dimension U of the pressed surface 14 on the cutting insert 11 side is made larger than the width dimension W of the pressing surface 7 on the insert mounting seat 8 side. The width dimension W is reduced, and the pressing position PP ′ is positioned in the range of W / 8 to 4W / 9 inward from both ends in the width direction of the pressing surface 7.

  The insert detachable tool to which the clamping mechanism of the cutting insert 11 configured as described above is applied is fixed by sandwiching the cutting insert 11 with an insert mounting seat 8 formed at the tip of the holder 1, and a lathe or machining center. The cutting blade of the cutting insert 11 which is supported by a machine tool such as the like and is moved relative to the workpiece in a state where the cutting insert 11 is pressed against the workpiece rotating at high speed, and protrudes from the tip side of the holder 1. 17 is used to cut the outer surface and end surface of the workpiece.

  In the clamping mechanism of the cutting insert 11 having the above-described configuration, the pedestal surface 5 and the seating surface 15 are a pair of support positions SS ′ and a pressing surface in a cross section perpendicular to the longitudinal direction of the cutting insert 11 of the insert mounting seat 8. 7 and the pressed surface 14 are in contact with each other at a pair of pressing positions PP ′, that is, the cutting insert 11 is fixed at four points, and the insert detachable tool to which this clamping mechanism is applied is used as the slit 3A of the head portion 3. 2 in the direction along the arrow (the direction of the arrow X in FIGS. 2 and 6), the component force of feeding is the two of one pressing position P ′ located on the feeding direction side and one supporting position S ′. Since it can receive in a point, the movement of the cutting insert 11 by feed force can be prevented. Therefore, even when the insert detachable tool is laterally fed, the cutting insert 11 can be firmly fixed, the cutting insert 11 can be prevented from being damaged or dropped, and the processing accuracy of the insert detachable tool is deteriorated. Can be prevented.

  Further, since the pair of pressing positions PP ′ are arranged between the pair of supporting positions SS ′, a bending moment is generated in the upper jaw portion 3B, and the pressing portion 6 is inclined and approaches the pedestal 4, Even when the center line of the pressing portion 6 and the center line of the pedestal 4 are shifted and approach each other, the cutting insert 11 can be more stably fixed.

  Here, the mounting hole 23 to which the clamp screw 22 is attached is provided in the vicinity of the axis L of the shank portion 2, and the insert mounting seat 8 projects along the axis L from a position away from the axis L of the shank portion 2. Therefore, when the clamp screw 22 is screwed and the upper jaw portion 3B is elastically deformed toward the lower jaw portion 3C, a bending moment is generated in the upper jaw portion 3B of the head portion 3, as shown in FIG. The upper jaw portion 3B comes into contact with the slit 3A in an inclined state.

In this way, even when the pressing portion 6 approaches the pedestal 4 at an angle θ with respect to the contact direction, as shown in FIG. 7, a pair of support positions SS ′ of the pedestal surface 5 and the seating surface 15 are provided. In between, a pair of pressing positions PP ′ of the pressing surface 7 of the pressing portion 6 and the pressed surface 14 of the cutting insert 11 will be located, and even when the pressing portion 6 is further pressed to the base 4 side, The cutting insert 11 is stably supported at the pair of support positions SS ′, and the cutting insert 11 can be reliably prevented from tilting.

  In addition, in the cross section orthogonal to the axis L as shown in FIG. 8, when the center line of the pressing portion 6 approaches the center line of the pedestal 4 while being shifted in the width direction by δ, the pressing surface 7 of the pressing portion 6 The pressed surface 14 of the cutting insert 11 comes into contact at one pressing position P ′ located between a pair of support positions SS ′ of the pedestal surface 5 and the seating surface 15. When the pressing portion 6 is further pressed toward the pedestal 4 in this state, as shown in FIG. 9, at another pressing position P located between a pair of support positions SS ′ of the pedestal surface 5 and the seating surface 15. It comes into contact and is supported at four points, and the cutting insert 11 can be stably fixed.

  Therefore, even when the pressing portion 6 approaches the pedestal 4 while being inclined with respect to the contact direction, or when the center line of the pressing portion 6 is shifted from the center line of the pedestal 4, the cutting insert 11 may be inclined. Thus, the cutting angle and clearance angle of the cutting edge 17 of the cutting insert 11 are not distorted, the machining accuracy of the insert detachable tool can be greatly improved, and an excessive load is prevented from being applied to the cutting insert 11. Thus, the cutting insert 11 can be more reliably prevented from being damaged or dropped off.

  Further, in the clamping mechanism of the cutting insert 11 having the above-described configuration, the pressing surface 7 and the pedestal surface 5 of the insert mounting seat 8 are constituted by a pair of inclined flat surfaces 7A, 7B, 5A, and 5B. The inclined planes 7A, 7B, 5A, and 5B can be accurately formed at a predetermined crossing angle.

  The pressing surface 7 and the pedestal surface 5 come into contact with each other, and a pair of convex curved surfaces 14A, 14B, 15A, 15B having roundness that is convex toward the inclined planes 7A, 7B, 5A, 5B, respectively. The convex surface 14A, 14B, 15A, 15B is a pressed surface 14 and a seating surface 15 formed in a concave V-shape by the above-mentioned, and the support position SS ′ on the convex surfaces 14A, 14B, 15A, 15B. The pressing position PP ′ always comes into contact with the inclined planes 7A, 7B, 5A, and 5B. The supporting position SS ′ and the pressing position PP ′ are a pair of inclined planes 7A, 7B, 5A, and 5B or a convex curved surface 14A. Even if there is a slight error in the crossing angle of the concave and convex V-shaped by 14B, 15A, and 15B and the curvature radius of the convex curved surface, it moves slightly in the width direction along this convex curved surface 14A, 14B, 15A, 15B. There can therefore be controlled so as to be located in the support position SS ', the predetermined range reliably in the widthwise direction of the pressing position PP'.

  Moreover, a pair of such convex curved surfaces 14A, 14B, 15A, and 15B forms a concave V-shaped cross section, and abuts against the convex V-shaped inclined planes 7A, 7B, 5A, and 5B, which are inclined planes, respectively. Therefore, even if an excessive load is applied to the cutting insert 11 from the cutting edge 17 during cutting, the convex curved surfaces 14A, 14B, 15A, and 15B are guided by the inclined planes 7A, 7B, 5A, and 5B. The insert 11 is less likely to shift and can hold the cutting insert 11 more stably.

  In addition, such convex curved surfaces 14A, 14B, 15A, and 15B are not only microscopically contacted with one point of the support position SS ′ and the pressing position PP ′ but also in surface contact in a range having a certain width around the periphery. Since they are brought into contact with the inclined planes 7A, 7B, 5A, and 5B in a close state, higher stability and mounting strength can be ensured. Therefore, according to the clamp mechanism having the above-described configuration, the cutting insert 11 can be stably and highly accurate without requiring high molding accuracy for the pressing surface 7, the pedestal surface 5, the pressed surface 14 and the seating surface 15 as described above. This makes it possible to achieve smooth and highly accurate grooving and parting off.

  However, the pressing surface 7 and the pedestal surface 5 are thus formed in a convex V shape by the inclined planes 7A, 7B, 5A, 5B, and the pressed surface 14 and the seating surface 15 are formed as convex curved surfaces 14A, 14B, 15A, Even if it is formed in a concave V shape by 15B, the angles α and β formed by the convex V shape by the inclined planes 7A, 7B, 5A and 5B are small, or the support position SS of the convex curved surfaces 14A, 14B, 15A and 15B. ', If the radius of curvature at the pressing position PP' is large, the variation of the support position SS 'and the pressing position PP' when there is a molding error in the inclined planes 7A, 7B, 5A, 5B increases, and stability is increased. May be damaged.

  On the other hand, when the angles α and β formed by the convex V-shape are too large and the pedestal surface 5 and the pressing surface 7 by the pair of inclined planes become nearly flat, a load acts on the cutting insert 11 in the width direction. Stability cannot be secured, and even if the curvature radius of the convex curved surfaces 14A, 14B, 15A, 15B is too small, the contact with the inclined plane may be close to line contact, and the above-described effect of surface contact may be impaired. is there.

  For this reason, as in this embodiment, it is desirable that the angles α and β formed by the convex V-shape be 110 ° to 160 °, and the curvature radii of the convex curved surfaces 14A, 14B, 15A, and 15B are dimensions in the width direction. The width is preferably in the range of 0.4 × U to 4.0 × U with respect to the width dimension U of the non-small surface. The convex curved surfaces 14A, 14B, 15A, and 15B only need to have such a radius of curvature at least at the support position SS ′ and the pressing position PP ′. If they do not interfere with each other, they may have different radii of curvature, may be inclined flat surfaces, or may be concave curved surfaces depending on circumstances.

  On the other hand, in the clamp mechanism having the above configuration, as described above, the pair of pressing positions PP ′ between the pressing surface 7 and the pressed surface 14 and the pair of supporting positions SS ′ between the pedestal surface 5 and the seating surface 15 are predetermined in the width direction. Based on this, in the present embodiment, the pair of support positions SS ′ is 1 / of the width dimension W from the both ends in the width direction of the base 4 where the width dimension W is not large. The pedestal 4 is positioned within the range of 10 to 1/3, and the pair of pressing positions PP ′ is positioned inside the pair of support positions SS ′ and the width dimension W is not large. Are located in the range from 1/8 to 4/9 of the width dimension W from both ends in the width direction.

  Therefore, according to the present embodiment, the mounting stability of the cutting insert 11 can be further improved by bringing the seat surface 5 and the seating surface 15 into contact with each other at the pair of support positions SS ′ located within the above range. For example, it is possible to reliably prevent the cutting insert 11 from tilting even when a large load is applied to one side of the cutting blade 17 in the width direction during cutting.

  That is, when the pair of support positions SS ′ is disposed on the inner side of this range, the interval between the pair of support positions SS ′ is too small, and the pedestal surface 5 and the seating surface 15 are one in the widthwise central portion. The pair of pressing positions PP ′ disposed between the two points approaches one point, and the cutting insert 11 has the above-mentioned cross section when a large load is applied in the width direction during cutting. There is a risk of tilting. On the other hand, when the pair of support positions SS ′ are located outside the range, the clamp screw 22 is provided at the corner on the outer side of the surface having a small dimension in the width direction (the pedestal surface 5 of the pedestal 4 in this embodiment). There is a risk that the clamping force due to will be concentrated and the corners may be damaged or deformed.

  Furthermore, when the pressing surface 7 and the pressed surface 14 come into contact with each other at the pressing position PP ′ in the above range, the pressing position PP ′ is reliably arranged on the inner side in the width direction of the support position SS ′, and is more stable. Since the cutting insert 11 can be fixed and the pair of pressing positions PP ′ does not concentrate at one point near the center of the cutting insert 11 in the width direction, the insert detachable tool to which the clamp mechanism of the present embodiment is applied. Can be reliably received at two points of one pressing position P ′ and one supporting position S ′. When the insert detachable tool is laterally fed, the cutting insert 11 can be received. Can be reliably prevented from being damaged or dropped off, and deterioration of the processing accuracy of the insert detachable tool can be reliably prevented.

Next, a second embodiment of the present invention will be described. FIG. 10 is a cross-sectional view showing the second embodiment.
In the second embodiment, as shown in FIG. 10, the pressing surface 37 of the pressing portion 36 and the pedestal surface 35 of the pedestal 34 are formed in a convex V shape by a pair of inclined planes 37A, 37B, 35A, and 35B, respectively. In addition, the crossing angles of the inclined planes 37A, 37B, 35A, and 35B, that is, the angles α and β formed by the convex V-shape are equal to each other and set to 160 °. The pressing portion 36 and the pedestal 34 constitute an insert mounting seat.

  Further, as shown in FIG. 10, the pressed surface 44 of the cutting insert 41 is provided with a pair of convex curved surfaces 44A and 44B that approach each other so as to go downward as it goes inward in the width direction of the insert body. Due to the convex curved surfaces 44A and 44B, the pressed surface 44 is formed in a substantially concave V shape in a cross section orthogonal to the longitudinal direction of the insert body. On the other hand, as shown in FIG. 10, the seating surface 45 of the cutting insert 41 is provided with a pair of convex curved surfaces 45A and 45B that approach each other so as to go upward as they go inward in the width direction of the insert body. The seating surface 45 is formed by the convex curved surfaces 45 </ b> A and 45 </ b> B so as to form a substantially concave V shape in a cross section orthogonal to the longitudinal direction of the insert body.

  The convex curves 44A, 44B, 45A, and 45B are arcuate in a cross section perpendicular to the longitudinal direction of the insert body, and the radii of curvature of the arcs are all the same. Here, the intersection angle φ of the tangent at the intersection of the pair of convex curves 44A and 44B forming the pressed surface 44 is larger than the intersection angle γ of the tangent at the intersection of the pair of convex curves 45A and 45B forming the seating surface 45. Has been.

  Therefore, the intersection angle φ of the tangent at the intersection of the pair of convex curves 44A and 44B forming the pressed surface 44 formed on the upper surface of the convex portion of the cutting insert 41 is a pair of seating surfaces 45 formed on the lower surface of the insert body. A convex V-shape in which the pressing surface 37 of the pressing portion 36 and the pedestal surface 35 of the pedestal 34 have the same inclination angle is assumed to be larger than the intersection angle γ of the tangent line at the intersection of the convex curves 45A and 45B. As shown in FIG. 10, the pair of pressing positions PP ′ of the pressing surface 37 and the pressed surface 44 is positioned between the pair of supporting positions SS ′ of the seating surface 45 and the pedestal surface 35. Will do.

  In the clamping mechanism of the cutting insert having such a configuration, as shown in FIG. 11, even when the pressing portion 36 approaches the pedestal 34 at an angle θ with respect to the contact direction, the pedestal surface 35 and the seating surface 45. A pair of pressing positions PP ′ of the pressing surface 37 of the pressing portion 36 and the pressed surface 44 of the cutting insert 41 are positioned between the pair of supporting positions SS ′. Even when pressed to the side, the cutting insert 41 is stably supported at the pair of support positions SS ′, and the cutting insert 41 can be reliably prevented from being inclined.

  Also, as shown in FIG. 12, when the center line of the pressing part 36 approaches the center line of the pedestal 34 with a deviation of δ, the pressing surface 37 of the pressing part 36 and the pressed surface 44 of the cutting insert 41 are Contact is made at one pressing position P ′ located between the pair of support positions SS ′ of the pedestal surface 35 and the seating surface 45. When the pressing portion 36 is further pressed against the pedestal 34 in this state, it comes into contact at another pressing position P located between a pair of support positions SS ′ of the pedestal surface 35 and the seating surface 45 as shown in FIG. Therefore, the cutting insert 41 can be stably fixed.

In the present embodiment, the pressed surface of the cutting insert, a seating surface is formed both in a concave V-shape, the base surface of the insert mounting seat, but the pressing surface has been described both those formed in a convex V-shape However, the present invention is not limited thereto, and one of the pressed surface and the seating surface of the cutting insert may be formed in a concave V shape and the other may be formed in a convex V shape. However, when the pressing surface of the pressing portion is formed in a concave V shape, the outer portion of the concave V shape may come into contact with the pressed surface of the cutting insert when the pressing portion is inclined toward the pedestal. Therefore, it is not preferable to form the pressing surface of the pressing portion in a concave V shape.

In the second embodiment, the pressed surface and the seating surface are each formed by a pair of convex curves having arcs with the same radius of curvature, and the intersection angle of the convex curves is changed. The curvature radius of the arc to be changed may be changed.
Further, the crossing angle between the pressed surface and the seating surface and the crossing angle between the pressing surface and the pedestal surface may be appropriately changed.

It is a perspective view of a holder and a cutting insert of an insert detachable cutting tool to which an insert clamping mechanism according to a first embodiment is applied. 1 is a top view of an insert detachable cutting tool to which an insert clamping mechanism according to a first embodiment is applied. FIG. It is a side view of the insert detachable cutting tool to which the insert clamping mechanism according to the first embodiment is applied. 1 is a front view of an insert detachable cutting tool to which an insert clamping mechanism according to a first embodiment of the present invention is applied. FIG. It is a front view of the cutting insert in a 1st embodiment. It is sectional drawing which shows the clamped state of the cutting insert in 1st Embodiment. It is sectional drawing which shows a clamp state when a press part inclines with respect to a contact direction in 1st Embodiment, and approaches a base. It is sectional drawing which shows the contact state when the centerline of a press part has shifted | deviated from the centerline of the base in 1st Embodiment, and approached. It is sectional drawing which shows the clamped state when the centerline of a press part shifts | deviates from the centerline of a base in 1st Embodiment, and approaches. It is sectional drawing which shows the clamp state of the cutting insert in 2nd Embodiment. It is sectional drawing which shows a clamp state when a press part inclines with respect to a contact direction and approaches a base in 2nd Embodiment. It is sectional drawing which shows the contact state when the centerline of a press part shifts | deviates from the centerline of a base in 2nd Embodiment, and approaches. It is sectional drawing which shows the clamped state when the centerline of a press part has shifted | deviated from the centerline of the base in 2nd Embodiment.

Explanation of symbols

1 Holder 3B Upper jaw (one jaw)
3C Lower jaw (the other jaw)
4, 34 Pedestal 5, 35 Pedestal surfaces 5A, 5B, 35A, 35B Inclined plane 6, 36 Pressing portion 7, 37 Pressed surface 7A, 7B, 37A, 37B Inclined plane 8 Insert mounting seat 11, 41 Cutting insert 14, 44 Covered Press surface 14A, 14B, 44A, 44B Convex curved surface 15, 45 Seating surface 15A, 15B, 45A, 45B Convex curved surface 22 Clamp screw

Claims (5)

A cutting insert provided with a pressing surface and a seating surface, which are in contact with the pressing surface and the pedestal surface, respectively, on an insert mounting seat provided at the tip of the holder with a pressing surface and a pedestal surface facing each other. A clamping mechanism for a cutting insert that clamps by inserting and clamping,
The tip of the holder is formed with a pair of jaws having one jaw and the other jaw, and the one jaw is provided with a pressing part on which the pressing surface is formed, The other jaw is provided with a pedestal on which the pedestal surface is formed,
In the cross section perpendicular to the longitudinal direction of the insert, the seating surface and the pedestal surface of the insert are supported at a pair of support positions spaced in the width direction, and the pressing surface and the pressed surface are in the width direction. Are pressed at a pair of pressing positions spaced apart from each other, and the pair of pressing positions are arranged between the pair of supporting positions in the width direction ,
Furthermore, at least one of the pressing surface and the pedestal surface and at least one of the pressed surface and the seating surface are convex V-shaped in a cross section perpendicular to the longitudinal direction of the insert. It is provided with a pair of inclined planes that are inclined so as to form a shape, and the other has a concave V shape with a pair of convex curved surfaces that are convex toward the inclined plane side. A cutting mechanism for the cutting insert.   In the cross section perpendicular to the longitudinal direction of the insert, the pair of support positions are both ends in the width direction of surfaces of the pedestal surface and the seating surface that are in contact with each other at the support positions and whose dimensions in the width direction are not large. 2. The cutting insert clamping mechanism according to claim 1, wherein the cutting insert clamping mechanism is positioned inward within a range of W / 10 to W / 3 with respect to the dimension W in the width direction.   In the cross section perpendicular to the longitudinal direction of the insert, the pair of pressing positions is a width direction of a surface of the pressing surface and the pressed surface that are in contact with each other at these pressing positions and whose dimension in the width direction is not large. The cutting insert clamping mechanism according to claim 1 or 2, wherein the cutting insert clamping mechanism is positioned in the range of W / 8 to 4W / 9 with respect to the dimension W in the width direction from both ends to the inside. The cross section perpendicular to the longitudinal direction of the insert, the pair of inclined planes are inclined in a direction intersecting at an intersecting angle of 110 ° to 160 ° . The cutting insert clamping mechanism described in 1. In the cross section perpendicular to the longitudinal direction of the insert, the radius of curvature of the convex curved surface at the pair of supporting positions and the pair of pressing positions is the pair of inclined planes and the pair of convex curved surfaces at the supporting position and the pressing position. 0.4 × U to the dimension U in the width direction of the surface of the pedestal surface and the seating surface that are in contact with each other and the surface of the pressing surface and the pressed surface that are not small in the width direction. The clamping mechanism for a cutting insert according to any one of claims 1 to 4, wherein the clamping mechanism has a range of 4.0 x U.

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