JP5287120B2 - Claw mechanism for throwaway rotary tool, tool body for throwaway rotary tool, and throwaway tip - Google Patents

Description

  The present invention relates to a throw-away rotary tool in which a throw-away tip is detachably mounted on a tool body as a cutting blade.

Conventionally, the throw-away tip is inserted into a slit-like tip mounting groove provided at the tip of the tool body, and the tip body is formed through a clamp hole provided perpendicular to the tool mounting groove. A throw-away end mill is known in which a throw-away tip is detachably mounted by screwing a clamp screw through a hole.
In order to improve the mounting accuracy and mounting rigidity of such a throw-away end mill, a cone receiving surface that is eccentric in the direction toward the rear end of the tool body is formed in the portion corresponding to the head cone surface of the fastening member in the side surface of the tip seat of the tool body. Has been proposed (see, for example, Patent Document 1).
JP-A-11-239911

  However, in the invention of the above-mentioned Patent Document 1, since the fixing of the throw-away tip in the tool rotation direction is performed only by pressing by the side surface portion of the tip seat based on the elastic deformation of the tool body, the groove width of the tip seat, Depending on the accuracy such as the flatness and the thickness of the throw-away tip, there is a possibility that the tip seat side surface portion and the throw-away tip are not in close contact with each other so that a gap is formed and the throw-away tip rotates and shifts during processing. Moreover, there is a possibility that the tip seat is worn by long-term use, and the throw-away tip is loosely attached.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a throw-away rotary tool and a throw-away tip clamping mechanism having stable and excellent mounting rigidity.

In order to achieve the above object, the present invention provides the following means. The invention includes a tool body that is rotated around an axis, and the chip mounting groove for mounting the tool body of the distal cutting insert is recessed and opens to the tip face of the tool body portion, said chip mounting A clamp hole into which a clamp screw used for mounting a throw-away tip formed so as to cross the groove is inserted, and a bottom surface for placing the throw-away tip and a side wall standing up from the bottom surface thrown with a bets in the vertical transverse cross section to the axis, the center line of the clamp holes intersecting inclined in the rotational direction rear side of the tool body with respect to the plane orthogonal to the side wall of the chip mounting groove Provide away-type rotary tools.

According to the present invention, by inserting the throw-away tip into the tip mounting groove and screwing the clamp screw through the mounting hole into the clamp hole, the tip of the tool body is elastic so that the groove width of the tip mounting groove is reduced. As a result, the throw-away tip is clamped by the tip of the tool body.
In this case, the clamp hole is formed so as to be oblique to a plane perpendicular to the side wall of the chip mounting groove in a cross-sectional view perpendicular to the axis, so that the throw away can be achieved by tightening the clamp screw. The tip is pressed against the side wall of the chip mounting groove while rotating around the axis, whereby the throw-away chip and the side wall of the chip mounting groove are brought into close contact with each other and fixed. This makes it possible to firmly fix the throw-away tip at a predetermined position in the tool rotation direction without depending on the machining accuracy of the chip mounting groove, etc., and the throw-away tip is displaced in the tool rotation direction during machining. Can be prevented.

In the above invention, the clamp hole may be inclined rearward in the tool rotation direction with respect to a plane perpendicular to the side wall of the tip mounting groove in a cross-sectional view perpendicular to the axis.
Moreover, in the said invention, it is preferable that the inclination | tilt angle of the said clamp hole is 30'-1 degree.
By doing so, the tip mounting groove that faces the tool rotation direction is pressed by the side wall of the tip mounting groove that faces the tool rotation direction while the slow way tip rotates in the tool rotation direction by tightening the clamp screw. It will be stuck and fixed to the side wall.

In the above invention, the clamp hole includes a counterbore for receiving the head of the clamp screw and a screw hole for screwing the screw portion of the clamp screw, and the counterbore is a screw. It is good also as being eccentric to the tool base end side with respect to the hole.
By doing this, by tightening the clamp screw, the throw-away tip is pulled into the tool base end side and pressed against the bottom surface side of the chip mounting groove, thereby being brought into close contact with the bottom surface of the chip mounting groove. It will be fixed. As a result, the throw-away tip can be firmly fixed at a predetermined position in the axial direction.

According to the throw-away rotary tool of the present invention, there is an effect that the mounting rigidity and the mounting stability are excellent.

Hereinafter, an embodiment of a throw-away rotary tool and a throw-way tip clamping mechanism according to the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIGS. 1A and 1B, the throw-away ball end mill according to the present embodiment is cut at a cylindrical tool body 1 rotated around an axis O and at the tip of the tool body 1. The throwaway tip is detachably mounted as the blade 11 and a clamp screw 20 for attaching the throwaway tip to the tool body 1.
The tool body 1 is made of high-speed steel, tool steel, alloy steel, stainless steel, cemented carbide, or the like, and a groove-shaped throwaway tip that opens to the tip surface of the tool body 1 is attached to the tip portion. There are provided a chip mounting groove 2 and a clamp hole 5 into which a clamp screw 20 used for mounting a throw-away chip crossing the chip mounting groove 2 is inserted.

  As shown in FIG. 2A, the tip mounting groove 2 is formed in a plane direction including the axis O from the center of the tip of the tool body 1 toward the base end so as to bisect the tip of the tool body 1. A pair of side walls comprising a bottom surface 3 made of a flat surface perpendicular to the axis O on which the chip body 10 is placed, and a flat surface parallel to the axis O rising from both ends of the bottom surface 3. 4 and 4. The tip mounting groove 2 formed so as to bisect the tip end portion of the tool main body 1 allows the tip end portion of the tool main body 1 to be elastically deformed in the direction of narrowing the groove width of the tip mounting groove 2. In this case, in order to make the elastic deformation of the tip portion of the tool body 1 smoother, it is preferable to cut out a part of the bottom surface 3 of the chip mounting groove 2 to provide the recess 9. The recess 9 is formed, for example, with a tip mounting groove on the counterbore 6 side of the tool body 1 in order to smooth elastic deformation at the tip of the tool body 1 on the side of the counterbore 6 divided by the chip mounting groove 2. 2 is formed so as to cut out a corner where the side wall 4 and the bottom surface 3 intersect in an arc shape.

  As shown in FIG. 2 (b), the clamp hole 5 is formed so as to extend perpendicularly to the axis O toward the outer peripheral portion of the tool body 1, and on one side wall 4 side of the chip mounting groove 2. A counterbore 6 for receiving the head 22 of the clamp screw 20 that opens to the side, and a screw hole 7 for screwing the screw portion 23 of the clamp screw 20 that opens to the other side wall 4 of the chip mounting groove 2. And a cylindrical portion 8 for receiving a shaft portion 21 of a clamp screw 20 integrally formed between the counterbore 6 and the screw hole 7. The center lines n1, n2, and n3 of the counterbore hole 6, the screw hole 7, and the cylindrical portion 8 are configured to coincide with each other in a cross-sectional view perpendicular to the axis O. The counterbore 6 includes a tapered portion formed so as to gradually increase in diameter toward the opening on the outer peripheral portion side of the tool body 1, and receives the head portion 22 of the clamp screw 20 at the tapered portion. ing. The screw hole 7 has a substantially cylindrical shape, and a female screw-like groove is formed on the inner peripheral surface thereof. The cylindrical portion 8 is formed in a circular cross section.

As shown in FIG. 2B, the clamp hole 5 configured in this manner obliquely intersects with a plane P perpendicular to the side wall 4 of the chip mounting groove 2 in a cross-sectional view perpendicular to the axis O. The center line N of the clamp hole 5 is inclined rearward in the tool rotation direction T with respect to the plane P orthogonal to the side wall 4 of the tip mounting groove 2. The inclination angle α of the clamp hole 5 is preferably set within a range of 30 ′ to 1 °, and is set to 45 ′, for example.
Further, as shown in FIG. 2A, the counterbore 6 of the clamp hole 5 is eccentric to the tool base end side with respect to the screw hole 7 and the cylindrical portion 8 in a longitudinal sectional view along the axis O. The center line n1 of the counterbore 6 is arranged so as to be slightly displaced from the screw holes 7 and the center lines n2 and n3 of the cylindrical portion 8 toward the bottom surface 3 of the chip mounting groove 2. The eccentric amount Δ of the clamp hole 5 is preferably set within a range of 0.05 mm to 0.15 mm, and is set to 0.1 mm, for example.

  The throw-away tip has a flat-plate-shaped tip body 10 and a cutting edge formed at a side ridge portion of a pair of side surfaces 14 and 14 facing each other with a gap in the tip thickness direction at the tip portion of the tip body 10. 11 and 11 and a mounting hole 12 formed through the central portion of the chip body 10 in the thickness direction of the chip. The chip body 10 is made of high-speed steel, cemented carbide, cermet, ceramics, ultra-high pressure sintered body, etc., and is seated on the rear end of the chip body 10 in contact with the bottom surface 3 of the chip mounting groove 2 in the chip mounting state. A surface 13 is provided. The thickness of the chip body 10 is slightly smaller than the width of the chip mounting groove 2, and the tip end portion of the tool body 1 is elastically deformed by tightening the clamp screw 20, and one side wall 4 of the chip mounting groove 2 is the other side. The side surfaces 14 and 14 of the chip body 10 are set so as to contact the side walls 4 and 4 of the chip mounting groove 2 by being displaced so as to be close to the side wall 4 of the chip. The cutting edge 11 includes an outer peripheral blade disposed on the outer peripheral surface of the tool main body 1 and a substantially spherical bottom blade disposed on the distal end surface of the tool main body 1. The mounting hole 12 is configured such that the shaft portion 21 of the clamp screw 20 is fitted therein, and a cylindrical surface that engages with the shaft portion 21 of the clamp screw 20 is provided on the inner peripheral surface thereof. From the viewpoint of improving the mounting accuracy, the chip body 10 has a high degree of accuracy such as the parallelism of both side surfaces 14, 14, the flatness of the side surface 14, the flatness of the seating surface 13, and the cylindricity of the mounting hole 12. It has been finished.

  The clamp screw 20 is made of a high-strength material such as a steel material, and engages with a cylindrical shaft portion 21 and a tapered portion of a counterbore 6 on an outer peripheral surface formed integrally with one end of the shaft portion 21. A head portion 22 having a tapered surface and a screw portion 23 having a male screw-like groove on the outer peripheral surface formed integrally with the other end are provided. From the viewpoint of improving the mounting accuracy, the shaft portion 21 of the clamp screw 20 is finished so that the dimensional accuracy, cylindricity and the like are high.

  The throw-away ball end mill configured in this way is used by being attached to the spindle of the machine tool via a holder, and the steel fixed to the table of the machine tool while rotating the tool body 1 around the axis O, etc. Cutting is performed by moving the workpiece while being in contact with the workpiece, and it is used for machining mechanical parts represented by a mold. When the used cutting edge 11 is damaged, the throw-away tip is replaced with a new one.

The operation of the throw-away ball end mill according to this embodiment configured as described above will be described below.
According to the throw-away ball end mill according to this embodiment, the chip body 10 is inserted into the chip mounting groove 2 and placed so that the seating surface 13 of the chip body 10 contacts the bottom surface 3 of the chip mounting groove 2. When the clamp screw 20 is screwed into the clamp hole 5 through the mounting hole 12 of the chip body 10, the tip of the tool body 1 divided by the chip mounting groove 2 on the counterbore 6 side is the groove of the chip mounting groove 2. By being elastically deformed so as to narrow the width, the side surface 14 of the chip body 10 is pressed against the side wall 4 on the side of the counterbore 6 of the chip mounting groove 2, and the chip body 10 is clamped by the tip of the tool body 1. The

  In this case, according to the throw-away ball end mill according to the present embodiment, the clamp hole 5 has a plane P whose center line N is orthogonal to the side wall 4 of the chip mounting groove 2 in a cross-sectional view perpendicular to the axis O. The shaft portion 21 of the clamp screw 20 that comes into contact with the inner peripheral surface of the mounting hole 12 of the chip body 10 is tightened by tightening the clamp screw 20. Then, a force for rotating the tip body 10 in the tool rotation direction T is applied, and the tip body 1 is brought into contact with the side wall 4 of the tip mounting groove 2 while rotating around the axis O of the tool body 1. At the same time, since the side wall 4 on the counterbore 6 side of the chip mounting groove 2 is elastically deformed so as to be close to the side wall 4 side on the screw hole 7 side, the side surface 14a of the chip body 10 facing the tool rotation direction T rear is formed. It is pressed by the side wall 4a facing the tool rotation direction T of the chip mounting groove. As a result, the side surface 14a of the chip body 10 facing the tool rotation direction T and the side wall 4a of the chip mounting groove 2 facing the tool rotation direction T are brought into close contact with each other and positioned in the tool rotation direction, that is, the cutting direction T. The main body 10 is fixed to the chip mounting groove 2.

  More specifically, referring to FIG. 3, the chip body 10 has the clamp screw 20 in a state where it is slightly inclined so that the center line S of the mounting hole 12 and the center line N of the clamp hole are parallel to each other. By screwing, first, the outer peripheral portion of the side surface 14a facing toward the rear of one tool rotation direction T is brought into contact with the outer peripheral portion of the side wall 4a facing the tool rotation direction T of the tip mounting groove 2 at the contact point A. Next, the outer peripheral portion of the side surface 14a facing the rear side of the other tool rotation direction T is a contact point B that is in a point-symmetrical position with the contact point A on the outer peripheral portion of the side wall 4a facing the tool rotation direction T of the tip mounting groove 2. Contacted. Next, the opening in the tool rotation direction T on the inner peripheral surface on the contact point A side of the mounting hole 12 is brought into contact with the outer peripheral surface on the head 22 side of the shaft portion 21 of the clamp screw at the contact point C. And the tool rotation direction T front side opening part in the inner peripheral surface by the side of the contact point B of the attachment hole 12 is a point-symmetrical position with the contact point C in the screw part 22 side outer peripheral surface of the axial part 21 of a clamp screw. Contact is made at point D.

  That is, while the tip body 10 rotates about the axis O in the tool rotation direction T, the tip body 10 is brought into contact with these four contact points A, B, C, and D almost simultaneously, and the counterbore hole of the tip mounting groove 2 When the side wall 4 on the 6th side is displaced toward the screw hole 7 side and presses the chip body 10, the side wall 4a, 4a of the chip mounting groove 2 facing the tool rotation direction T faces the rear side of the chip body 10 in the chip rotation direction T. A force pressing the side surfaces 14a and 14a is applied. Under this pressing force, the side surface 14a of the chip body 10 facing the chip rotation direction T and the side wall 4a of the chip mounting groove 2 facing the tool rotation direction T are brought into close contact, and the screw of the chip mounting groove 2 facing the tool rotation direction The side wall 4a on the hole 7 side is used as a reference plane and is positioned and fixed in the tool rotation direction T.

  Therefore, unlike the conventional case where the tip body is brought into contact with the side wall of the tip mounting groove only by pressing based on the elastic deformation of the tip end portion of the tool body, in addition to this, the tool rotation direction of the tip mounting groove 2 The force pressing the side surfaces 14a, 14a facing the tip rotation direction T of the tip body 10 from the side walls 4a, 4a facing the T acts to firmly fix the tip body 10 at a predetermined position in the tool rotation direction T. It becomes possible and has excellent mounting rigidity. As a result, even if a large load is applied during machining, the tip body 10 does not move back and forth in the tool rotation direction T, so that high mounting rigidity and mounting accuracy can be maintained, and mounting stability is improved. Excellent.

  Further, unlike the conventional chip body that is supported by surface contact, the chip body 10 is supported at four points A, B, C, and D. Therefore, the width dimension of the chip mounting groove 2 and the chip body The chip body 10 can be stably mounted at a predetermined position regardless of the accuracy such as the thickness dimension of 10, and the mounting rigidity is excellent. As a result, it is not necessary to finish the tip mounting groove 2 with high precision by polishing the side wall 4 of the tip mounting groove 2 for the purpose of improving the mounting rigidity as in the prior art. The manufacturing cost can be reduced by shortening. In addition, since it does not depend on the machining accuracy of the chip mounting groove 2, the mounting rigidity can be maintained even when the chip mounting groove 2 is worn due to cutting, and the tool life is improved.

  In particular, a stable pressing force is ensured on the contact surfaces 4a and 14a between the chip body 1 and the chip mounting groove immediately below the cutting edge 11, which is the most important in terms of mounting rigidity and mounting accuracy. It is possible to obtain excellent mounting rigidity and mounting accuracy, and extremely excellent mounting stability.

  Further, the counterbore hole 6 of the clamp hole 5 is formed so as to be eccentric to the tool base end side with respect to the screw hole 7 and the cylindrical portion 8, so that the tool base 10 rotates while the tip body 10 is rotated by tightening the clamp screw 20. The seating surface 13 of the chip body 10 is brought into contact with the bottom surface 3 of the chip mounting groove 2 and pressed toward the bottom surface 3 side of the chip mounting groove 2. As a result, the chip body 10 is positioned in the tool rotation direction T, and at the same time, is positioned in the direction of the axis O with the bottom surface 3 of the chip mounting groove 2 as a reference plane, and is fixed to the chip mounting groove 2. . Therefore, it is possible to stably fix the chip body 10 at a predetermined position in the tool rotation direction T and the axial direction O regardless of the machining accuracy of the chip mounting groove 2, and to improve mounting rigidity and mounting stability. Further improvement can be achieved.

  Thus, according to the throw-away ball end mill according to the present embodiment, since it has excellent mounting rigidity and mounting stability, generation of chatter vibrations due to displacement of the tip body 10, chipping of the blade portion, finished surface It is possible to prevent the deterioration of roughness and the like, and the machining accuracy and tool life are improved.

  In the present embodiment, the inclination angle α of the clamp hole 5 is set to 45 ′. However, the present invention is not limited to this and can be any other angle. In this case, the inclination angle α of the clamp hole 5 is preferably set within a range of 30 ′ to 1 °. If the inclination angle α exceeds 1 °, the restraint force of the chip body 10 by the clamp screw 20 is too strong, and a large load is applied to the mounting hole 12, the clamp hole 5 and the clamp screw 20 to cause wear, plastic deformation, and the like. This is because there is a possibility that the tool life may be shortened, and that if the inclination angle α is smaller than 30 ′, the pressing force may not be sufficiently secured. Further, instead of tilting the clamp hole 5 to the rear side in the tool rotation direction T, the clamp hole 5 may be tilted to the front side in the tool rotation direction T. In this case, the tip body 10 is fixed in close contact with the side wall 4 of the tip mounting groove 2 while rotating in the direction opposite to the tool rotation direction T.

In addition, although the eccentric amount Δ of the clamp hole 5 is set to 0.1 mm, the present invention is not limited to this and can be any other angle. In this case, the eccentric amount Δ of the clamp hole is preferably set within a range of 0.05 mm to 0.15 mm. Moreover, it is good also as not providing such an eccentric mechanism, and it is good also as employ | adopting the positioning means to the axis line O direction which consists of another structure instead of this.
Further, a corner 9 where the side wall 4 and the bottom surface 3 of the chip mounting groove 2 intersect on the counterbore 6 side of the tool body 1 is cut out in an arc shape, and a concave portion 9 having a substantially circular shape in a longitudinal sectional view along the axis O is formed. However, the position, shape, length, etc. of the recess 9 are not particularly limited, and the recess 9 may not be provided. For example, as shown in FIG. 4A, the concave portion 9 may be formed by cutting away from the bottom surface 3 on the counterbore 6 side of the chip mounting groove 2 toward the tool base end side. As shown in FIG. 4B, the chip mounting groove 2 may be formed by cutting away from the side wall 4 toward the tool outer peripheral side. As shown in FIG. 4 (c), the tip mounting groove 2 may be formed by cutting out from the center portion of the bottom surface 3 toward the tool base end side. As shown in FIG. 4D, the chip mounting groove 2 may be formed by cutting obliquely from the corner where the side wall 4 and the bottom surface 3 intersect to the tool outer peripheral side and the tool base end side. Further, the shape of the concave portion 9 is not particularly limited, and may be any other shape, for example, a substantially rectangular shape as shown in FIGS. Can do.

In the above embodiment, the throw-away ball end mill has been described as an example of the throw-away rotary tool and the throw-away tip clamping mechanism according to the present invention. However, the present invention is not limited to this, and the radius end mill is not limited thereto. , Square end mill, drill, reamer, boring cutter, etc.
Further, the present invention is not limited to the throw-away rotary tool, and can be diverted to a throw-away turning tool such as a cutting tool that is used by rotating a workpiece while fixing the tool to a lathe or the like. For example, when it is applied to a round shank tool having a cylindrical shank such as a boring tool or a boring tool, the chip body 10 is rotated around the tool center axis by tightening a clamp screw, and the chip mounting groove Will be firmly positioned and fixed firmly at a predetermined position in the cutting direction. As a result, there is an advantage that the reproducibility of the edge position when the tip body 10 is replaced is excellent.
It can also be diverted to joints that require high precision and strength.

It is a figure which shows the throw-away type ball end mill which concerns on one Embodiment of this invention, (a) is a perspective view, (b) is a front view which shows the front-end | tip part. (A) is the longitudinal cross-sectional view cut | disconnected by the plane in alignment with XX of FIG.1 (b), (b) is the cross-sectional view cut | disconnected by the plane in alignment with YY of FIG.1 (b). is there. It is a cross-sectional view explaining the clamp mechanism of the throw-away tip in the throw-away ball end mill of FIG. It is a longitudinal cross-sectional view which shows the modification of the throw-away type ball end mill of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tool main body 2 Tip mounting groove 3 Bottom face 4 Side wall 4a Side wall which faces tool rotation direction 5 Clamp hole 6 Counterbore hole 7 Screw hole 8 Cylindrical part 10 Tip body 12 Mounting hole 20 Clamp screw N Center line of clamp hole O Axis line P Tip A plane perpendicular to the side wall of the mounting groove T Tool rotation direction α Clamp hole inclination angle

Claims (6)

A tool body rotated about an axis,
And the chip mounting groove for mounting the cutting insert is recessed and opens to the tip face of the tool body to the tip of the tool body,
And a clamp hole clamping screw used for mounting the cutting insert is bored to intersect the chip mounting groove is inserted,
The tip mounting groove has a bottom surface for placing the throw-away tip and a side wall standing up from the bottom surface,
The throw characterized in that the center line of the clamp hole intersects with a plane perpendicular to the side wall of the tip mounting groove in an oblique direction to the rear side in the rotational direction of the tool body in a cross-sectional view perpendicular to the axis. Away rotary tool. The clamp hole includes a counterbore for receiving the head of the clamp screw and a screw hole for screwing the screw portion of the clamp screw, and the counterbore is a tool base with respect to the screw hole. The throw-away rotary tool according to claim 1, which is eccentric to the end side. A tool body for a throwaway rotary tool,
The tool body includes a tip mounting groove for sandwiching the throw-away tip at the tip thereof, and a clamp hole formed so as to intersect the tip mounting groove and for inserting a clamp screw.
For a throw-away rotary tool in which a center line of the clamp hole is inclined and intersects with the plane perpendicular to the side wall of the chip mounting groove in the rotational direction rearward in the transverse direction perpendicular to the axis. Tool body. The clamp hole includes a counterbore for receiving the head of the clamp screw and a screw hole for screwing the screw portion of the clamp screw, and the counterbore is a tool base with respect to the screw hole. The tool main body for the throw-away rotary tool according to claim 3, wherein the tool body is eccentric toward the end side. A throw-away tip having a mounting hole is inserted into a tip mounting groove provided at the tip of a tool body that rotates around a cylindrical axis, and the clamp hole drilled to intersect the tip mounting groove By screwing a clamp screw through the mounting hole, the throwaway tip is detachably attached to the tip mounting groove , and the tip mounting groove has a bottom surface for placing the throwaway tip, and a side wall standing up from the bottom surface. And a throw-away tip clamping mechanism in which a center line of the clamp hole inclines and intersects with a plane perpendicular to the side wall of the tip mounting groove in the tool rotation direction in a cross-sectional view perpendicular to the axis. . The clamp hole includes a counterbore for receiving the head of the clamp screw and a screw hole for screwing the screw portion of the clamp screw, and the counterbore is a tool base with respect to the screw hole. 6. The throw-away tip clamping mechanism according to claim 5, which is eccentric to the end side.

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