JP2007268693A - Holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holder capable of preventing damage to a holder without deteriorating a chip discharging property, and preventing resonance due to regular vibrations at the time of cutting. <P>SOLUTION: This holder 22 includes an approximate columnar holder body 47, and projecting parts 46. A plurality of the projecting parts 46 are formed in a peripheral direction R at different intervals, and timings for applying cutting resistance is differentiated, so as to restrain regular vibrations. Thickness W of a base end of each projecting part 46 is set based on the cutting resistance at the time of cutting, so as to prevent local deterioration of rigidity and breakage. A shape of each first chip accommodation space formation part 11 is formed based on the thickness W of the base end of each of the adjacent projecting parts 46, so that a first chip accommodation space 25 can be made as large as possible. Also, the chips can be smoothly discharged, so as to prevent damages of the holder 22 and prevent resonance due to regular vibrations at the time of cutting. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a holder to which a chip having a cutting blade can be attached and detached.

  When machining a work material, with a rotating tool that uses multiple throw-away inserts attached at the same time, the cutting force acts on the tool body from each throw-away tip every certain period of time. There is a problem that is likely to occur. In order to solve such a problem, a throw-away cutter according to a first conventional technique is disclosed (for example, see Patent Document 1). FIG. 7 is an enlarged front view of the first conventional throw-away cutter 1. FIG. 8 is a side view showing the throw-away cutter 1. In the first conventional throw-away cutter 1, a plurality of throw-away tips 2 are arranged at unequal intervals on a circumference centered on the rotation axis of the shank 3. This shifts the timing at which the cutting resistance acts on the shank 3 to prevent the occurrence of resonance and improve the finishing accuracy of the cut surface.

  In the second prior art end mill, the axial rake of the cutting edge of one tip among the plurality of tips attached to the outer peripheral portion of the end mill body is different from the axial rake of the cutting edge of the other tip. Composed. As a result, the cutting force of one tip is different from the cutting force of the other tip, so that the cutting force acting on the end mill body differs depending on the tip. Therefore, chatter generated in the end mill main body and resonance due to generation of regular vibration can be suppressed (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 11-333615 Japanese Utility Model Publication No. 63-86921

  In a rotary tool in which a large number of throw-away tips are attached and used at the same time, when the throw-away cutter 1 of the first prior art is configured as described above, the distance between the throw-away tips 2 is not equal. 7 are formed, as shown in FIG. 7, with respect to the thickness T of the chip mounting portion, a thin portion 4 having a dimension T11 and a thick portion 5 having a dimension T12 are formed. With such a configuration, the strength of the chip seating surface cannot be ensured, and the chip seating surface may be damaged.

  In the end mill of the second prior art described above, the shape and discharge direction of the chips differ depending on the axial rake, so that chips discharged from some chips may interfere with the chip pocket, and chip discharge. May be impaired.

  Accordingly, an object of the present invention is to provide a holder that can prevent damage to the holder without impairing chip dischargeability and can prevent resonance due to occurrence of regular vibration during cutting.

The present invention is a holder that can attach and detach a plurality of plate-shaped chips, and can mount each chip in a chip-mounted state in which the cutting edge of the chip protrudes from the outer peripheral surface,
A holder body formed in a substantially cylindrical shape;
One end of the holder axial direction includes a plurality of convex portions that are convex outward from the holder main body in the radial direction of the holder and formed at different intervals in the circumferential direction of the holder,
In a portion between two convex portions adjacent to each other in the holder circumferential direction, a chip housing space forming portion that forms a chip housing space for housing a chip in a chip mounted state;
A chip containing space forming portion is formed which opens the upper surface of the chip radially outward of the holder in a chip mounted state and forms a chip containing space extending from a virtual plane including the tip end surface of the holder along the axial direction of the holder. And
The dimension in the holder circumferential direction at the end of the holder on the holder body side is set based on the cutting resistance at the time of cutting the chip,
The shape of each chip accommodating space forming portion is a holder that is formed based on the dimension of each convex portion adjacent to one side in the holder circumferential direction.

  The present invention is also characterized in that the dimensions in the holder circumferential direction at the ends of the convex portions on the holder body side are equal to each other.

Furthermore, the present invention is capable of detaching a plurality of plate-shaped chips, a holder capable of mounting each chip in a chip mounted state in which the cutting edge of the chip protrudes from the outer peripheral surface, and a plurality of types mounted on the holder. A cutting tool including a tip,
The axial rake of at least one of the multiple types of chips is larger than the remaining type of axial rake,
The holder is a holder body formed in a substantially cylindrical shape;
One end of the holder axial direction includes a plurality of convex portions that are convex outward from the holder main body in the radial direction of the holder and formed at different intervals in the circumferential direction of the holder,
In a portion between two convex portions adjacent to each other in the holder circumferential direction, a chip housing space forming portion that forms a chip housing space for housing a chip in a chip mounted state;
A chip containing space forming portion is formed which opens the upper surface of the chip radially outward of the holder in a chip mounted state and forms a chip containing space extending from a virtual plane including the tip end surface of the holder along the axial direction of the holder. It is the cutting tool characterized by being performed.

Furthermore, the present invention can attach and detach a plurality of plate-shaped chips, a holder capable of mounting each chip in a chip mounted state in which the cutting edge of the chip protrudes from the outer peripheral surface, and a plurality of chips mounted on the holder. A cutting tool including
The holder is a holder body formed in a substantially cylindrical shape;
One end of the holder axial direction includes a plurality of convex portions that are convex outward from the holder main body in the radial direction of the holder and formed at intervals in the circumferential direction of the holder,
In a portion between two convex portions adjacent to each other in the holder circumferential direction, a chip housing space forming portion that forms a chip housing space for housing a chip in a chip mounted state;
A chip containing space forming portion is formed which opens the upper surface of the chip radially outward of the holder in a chip mounted state and forms a chip containing space extending from a virtual plane including the tip end surface of the holder along the axial direction of the holder. As
The interval between the chips in the holder circumferential direction consists of at least two different intervals,
The cutting tool is characterized in that an interval between the chip accommodating space forming portions in the holder circumferential direction is composed of at least two different intervals.

  Furthermore, the present invention is characterized in that the dimensions in the circumferential direction of the holder at the end on the holder body side of each convex portion are equal to each other.

  According to the present invention, the holder includes a substantially cylindrical holder main body and a convex portion protruding outward from the holder main body in the holder radial direction. A plurality of convex portions are formed at different intervals in the holder circumferential direction. A chip housing space forming portion and a chip housing space forming portion are formed in a portion between two convex portions adjacent in the holder circumferential direction. Accordingly, the chip accommodating space forming portions are formed at different intervals in the holder circumferential direction. As a result, the timing at which the cutting force acting on the holder acts on the holder can be shifted to suppress the occurrence of regular vibration. Therefore, chatter and resonance based on the cutting resistance from the tip to the holder can be suppressed.

  In the chip mounting state, each chip is housed in the chip housing space. The chip accommodating space opens the upper surface of the chip radially outward of the holder when the chip is mounted, so that chips separated from the work material during cutting can be discharged radially outward of the holder.

  The dimension in the holder circumferential direction at the end of each convex part on the holder body side is set based on the cutting resistance at the time of cutting the chip. Even if the convex portions have different dimensions in the circumferential direction of the holder, each convex portion is set based on the cutting resistance. Therefore, it is possible to reliably prevent the local rigidity from being lowered and being damaged. Moreover, the shape of each chip accommodation space formation part is each formed based on the said dimension of each convex part adjacent to one side of a holder circumferential direction. If the shape of each chip storage space is the same as in the prior art, when the distance between the protrusions is different from each other, the dimensions of the protrusions may become too small, and the strength may decrease. Since the shape of the chip accommodating space forming portion is set based on the size of each convex portion as in the invention, the shape of the chip accommodating space forming portion can be individually set based on the size of each convex portion. it can. By forming the chip accommodating space forming portion in this way, it is possible to reliably prevent the strength of the convex portion from being lowered. Therefore, since the chip accommodation space can be made as large as possible, the chips can be discharged smoothly. As a result, damage to the holder can be prevented without impairing the chip discharge performance, and resonance due to the occurrence of regular vibration during cutting can be prevented.

  Moreover, according to this invention, the dimension of the holder circumferential direction in the edge part by the side of the holder main body of each said convex part is mutually equal. Therefore, the minimum necessary strength can be ensured based on the cutting resistance at the time of cutting the dimensions of the convex portions. Thereby, the chip accommodating space can be maximized. Therefore, the strength of the holder can be ensured and the chip discharge performance can be further improved.

  Furthermore, according to the present invention, the axial rake of at least one of the plurality of types of chips is set to be larger than the remaining type of axial rake. Thereby, in the chip mounting state, the cutting resistance at the time of cutting varies depending on the axial rake of the chip, so that the cutting resistance acting on the holder varies depending on the chip. Accordingly, chatter generated in the holder and resonance due to generation of regular vibration can be suppressed. If the axial rake is different, the chip discharge direction during cutting will be different, but the chip can be discharged smoothly according to the axial rake of each chip by forming the shape of the chip storage space forming part based on the axial rake A chip-containing space forming portion can be formed. Thereby, chip discharge | emission property can be improved.

  Furthermore, according to the present invention, the interval between the chips in the holder circumferential direction is composed of at least two different intervals. Therefore, as described above, resonance due to generation of regular vibration during cutting can be prevented. Moreover, the space | interval of the said chip | tip accommodation space formation part in a holder circumferential direction consists of at least 2 or more different space | intervals. Thereby, the volume of the chip accommodating space can be set individually. Therefore, since each chip accommodation space can be made as large as possible based on the strength of each convex part, chips can be discharged smoothly. As a result, damage to the holder can be prevented without impairing the chip discharge performance, and resonance due to the occurrence of regular vibration during cutting can be prevented.

  Furthermore, according to this invention, the dimension of the holder circumferential direction in the edge part by the side of the holder main body of each said convex part is mutually equal. Therefore, the minimum necessary strength can be ensured based on the cutting resistance at the time of cutting the dimensions of the convex portions. Thereby, the chip accommodating space can be maximized. Therefore, the strength of the holder can be ensured and the chip discharge performance can be further improved.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. Portions corresponding to the matters described in the preceding forms in each embodiment are denoted by the same reference numerals, and overlapping description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  FIG. 1 is an enlarged front view showing an end mill 20 according to a first embodiment of the present invention. FIG. 2 is a side view showing the end mill 20. FIG. 3 is a perspective view showing the end mill 20. The end mill 20 is a cutting tool, and includes a plate-shaped throw-away tip 23 formed with a cutting edge 30 and a holder 22 to which the throw-away tip 23 is detachably attached. In the present embodiment, the holder 22 is configured to be capable of mounting a plurality, specifically five throw-away tips (hereinafter, also referred to as “chips”) 23.

  The holder 22 is formed in a substantially cylindrical shape with, for example, an aluminum alloy or a steel alloy. A shank portion that is held by the machining center is formed at the axial base end portion 16 of the holder 22. Further, a tip accommodating space forming portion 24 that holds the tip 23 in a state where the cutting edge 30 of the tip 23 protrudes from the outer peripheral surface 32 and the tip end surface 33 a is formed at the tip end portion 33 in the axial direction of the holder 22. The end mill 20 is configured with the chips 23 mounted on the holder 22.

  Hereinafter, the axis of the holder 22 is simply referred to as an axis L1. Further, the direction of the axial direction X along the axis L1 of the holder 22 and going from the rear end portion 16 which is the base end portion 16 of the holder 22 to the front end portion 33 is referred to as one axial direction X1, and from the front end portion 33 of the holder 22 The direction toward the base end portion 16 is referred to as the other axial direction X2. A direction toward the axis L1 along the radial direction Y of the holder 22 is referred to as a radial inner Y1, and a direction away from the axis L1 along the radial direction of the holder 22 is referred to as a radial outer Y2. In addition, the circumferential direction R around the axis L1 of the holder 22 and the direction that is the rotational direction of the end mill 20 is referred to as one circumferential direction R1, and the direction opposite to the rotational direction of the end mill 20 is referred to as the other circumferential direction R2.

  FIG. 4 is an enlarged side view showing the tip 33 of the holder 22. FIG. 5 is a front view showing the holder 22. 4 and 5, the chip 23 is virtually shown for easy understanding. Moreover, in FIG. 4 and FIG. 5, the 2nd chip accommodation space formation part 10 mentioned later is shown with the oblique line, for easy understanding. A groove 27 a that is recessed from the outer peripheral surface 32 and the distal end surface 33 a of the holder 22 is formed in the distal end portion 33 that is an end portion of the one axial direction X 1 of the holder 22, and includes the groove portion 27. A plurality of the groove portions 27 are formed at different intervals in the circumferential direction R, and five in the present embodiment. Therefore, the portion between the two groove portions 27 adjacent to each other in the circumferential direction R has a convex portion 46 that is convex outward in the radial direction Y2. The convex portion 46 protrudes radially outward Y2 from the cylindrical holder body 47, which is the radially inner portion 47 of the holder 22, and has a plurality of spacings in the circumferential direction R, and five in this embodiment. It is formed.

  The groove 27 includes a chip accommodating space forming part 24 that forms the chip accommodating space 26, a first chip accommodating space forming part 11 that forms the first chip accommodating space 25, and a second chip that forms the second chip accommodating space 12. And a housing space forming portion 10. That is, the chip accommodating space forming part 24, the first chip accommodating space forming part 11, and the second chip accommodating space forming part 10 are formed in the portion between the two convex portions 46 adjacent to each other in the circumferential direction R.

  The chip storage space 26 and the first chip storage space 25 are formed adjacent to each other. The first chip storage space 25 and the second chip storage space 12 are formed adjacent to each other. The 1st chip accommodation space 25 and the 2nd chip accommodation space 12 function as a chip accommodation space, and a 1st chip accommodation space formation part and a 2nd chip accommodation space formation part serve as a chip accommodation space formation part. Of the groove 27a, the region on the one side R1 side in the circumferential direction becomes the first chip accommodating space 25 and the second chip accommodating space 12, and the region on the other side R2 in the circumferential direction becomes the chip accommodating space 26. The chip accommodation space 26 is a space in which almost the entire chip 23 is accommodated in a chip mounting state in which the chip 23 is mounted on the holder 22. The first chip storage space 25 and the second chip storage space 12 are spaces for temporarily storing chips scraped off from the work material by the chip 23.

  The chip housing space forming part 24 forms a chip housing space 26. The chip accommodating space forming portion 24 has a seating surface 40 that is the surface of the other circumferential surface R2 with respect to the groove 27, and two side surfaces that are adjacent to the seating surface 40 and that are erected in the circumferential direction one R1. 41, 42. The seating surface 40 is formed in a flat surface, is bent from the front end surface 33a of the holder 22 and extends in the other axial direction X2, and is bent from the outer peripheral surface 32 of the holder 22 and extends inward in the radial direction Y1. As shown in FIG. 4, the seating surface 40 is formed so as to incline toward the other circumferential direction R2 toward the other axial direction X2 of the holder. Each seating surface 40 is set to have the same inclination angle γ with respect to the axis L1.

  The first side surface 41, which is one of the two side surfaces 41, 42, is adjacent to the edge of the seating surface 40 on the radially inner side Y <b> 1 side, and is erected on the seating surface 40 in one circumferential direction R <b> 1. The second side surface 42, which is the other of the two side surfaces 41, 42, is adjacent to the edge of the seating surface 40 in the axial direction on the other side X <b> 2 and is erected on the seating surface 40 in one circumferential direction R <b> 1. Further, the chip housing space forming portion 24 is formed with a screw hole 29 that is recessed from the seating surface 40 to the other circumferential direction R2. The screw hole 29 is formed with an inner screw and becomes a recess for fixing the chip 23.

  The first chip housing space forming part 11 forms a first chip housing space 25. The first chip accommodating space 25 opens the chip upper surface 15 radially outwardly Y2 in a chip-mounted state, and extends along the other axial direction X2 from the virtual plane including the tip end surface 33a of the holder. Accordingly, the first chip accommodating space 25 extends in the other axial direction X2 from the chip accommodating space 26 and is opened outward. The first chip accommodating space forming part 11 is adjacent to the first side surface 41 and extends in one circumferential direction R1 and is connected to the outer peripheral surface 32 of the holder 22 and adjacent to the second side surface 42. The first wall surface 44 extends from the two side surfaces 42 to the other axial direction X2.

  The second chip housing space forming part 10 forms a second chip housing space 12. The second chip accommodating space 12 faces the upper surface 15 of the chip 23 in the mounted state, and is spaced from the tip end surface 33a and the outer peripheral surface 32 of the holder, and is directed from the first chip accommodating space forming portion 11 toward the circumferential one R1. A second chip accommodating space 12 that is recessed is formed. The second chip housing space forming part 10 is immersed from the second wall surface 43 toward the circumferential direction R1. The second chip housing space forming portion 10 includes a first inclined surface 13 that is inclined radially outward Y2 from the portion where the first side surface 41 and the second wall surface 43 are continuous toward the one side R1 in the circumferential direction, and the first inclined surface 13. It has the 2nd inclined surface 14 which inclines in radial direction outward Y2 and continues to the 2nd wall surface 43 as it goes to the other circumferential direction R2 adjacent to the inclined surface 13. The first inclined surface 13 and the second inclined surface 14 are formed so as to bend in one circumferential direction R1 when viewed from the radially outer side Y2. Moreover, the 1st inclined surface 13 and the 2nd inclined surface 14 incline so that it may go to one axial direction X1 as the one axial direction X1 side goes to radial direction outward Y2. Moreover, the 1st inclined surface 13 and the 2nd inclined surface 14 incline so that the other axial direction X2 side may go to the other axial direction X2 as it goes to radial direction outward Y2.

  The second chip accommodating space forming part 10 is formed such that the central part in the axial direction X is disposed in the vicinity of the axial line of the chip 23 when viewed from the radially outer side Y2. Accordingly, the second chip accommodating space forming portion 10 is arranged so as to include the entire chip 23 as viewed from the radially outer side Y2.

  In such a second chip housing space forming portion 10, first, the flat end mill is displaced along the axial direction X from the columnar member serving as the precursor of the holder 22, and the first chip housing space is formed at the tip 33. A plane including the first wall surface 44 and the second wall surface 43 constituting the forming unit 11 is formed. If the first chip accommodating space forming portion 11 is processed as described above using a radius end mill or the like in which an R blade is formed at the corner, the first wall surface is formed at the intersection of the first wall surface 44 and the second wall surface 43. The corner R can be formed simultaneously with the processing of the 44 and the second wall surface 43. By forming such a corner R, it is possible to prevent the stress from concentrating on the intersecting portion and suppress the strength of the holder 22 from being lowered, thereby forming the first chip accommodating space forming portion 11. Next, a portion of the second wall surface 43 facing the chip accommodating space 12 is processed to be recessed in one circumferential direction R1 using a flat end mill or a ball end mill, thereby forming the first inclined surface 13 and the second inclined surface 14. . Thereby, the second chip accommodating space forming part 10 is formed.

  In this way, the second chip storage space 12 is opened facing the first chip storage space 25. A region surrounded by the seating surface 40, the side surfaces 41 and 42, the wall surfaces 43 and 44, and the inclined surfaces 13 and 14 is a groove 27a. In the groove 27a, a cross section perpendicular to the axis L1 is formed substantially in a fan shape.

  A through hole 17 is formed in the rear end portion 16 of the holder 22 so as to penetrate the rear end portion 16 and the first chip housing space forming portion 11. The through-hole 17 extends from the rear end surface 16 a along the axial direction X to the distal end portion 33 of the holder 22 through the radially inner portion 47 of the holder 22, and the distal end portion 33 accommodates the first chip in each groove portion 27. Branches toward the space forming portion 11. The through holes 17 are formed so as to extend along the direction inclined in the radially outward direction Y <b> 2 from the tip end portion 33 of the holder 22 toward one side in the axial direction X. As a result, the through-hole 17 opens toward the first chip accommodating space 25. The opening 18 to be opened is provided at a position close to the other X2 in the axial direction from the second chip housing space forming part 10. Accordingly, fluid, for example, air, water, and cutting fluid, is discharged from the opening 18 through the through hole 17 from the rear end portion 16 of the holder 22, so that fluid is applied to the vicinity of the upper surface 15 of the chip 23, and the second chip. It is possible to prevent chips from remaining undesirably in the accommodation space 12. Thereby, chip discharge | emission property can be improved.

  As described above, the convex portions 46 are formed at different intervals in the circumferential direction R. Therefore, the interval between the chips 23 in the circumferential direction R is at least two different intervals. In other words, in the chip mounting state, at least one chip 23 has a different distance to another chip 23 adjacent in the circumferential direction R. In the present embodiment, when the holder 22 is viewed from one side in the axial direction, the arrangement angle of the cutting blades 30 of each chip 23 is, for example, 60 degrees (α1) in order in the circumferential direction one R1 around the axis L1 of the holder 22. , 75 degrees (α2), 72 degrees (α3), 76 degrees (α4), and 77 degrees (α5). Therefore, the arrangement angle α1 is the smallest and the arrangement angle α3 is the largest. Accordingly, the two chips 23 adjacent to the convex portion 46 having the arrangement angle α1 have the smallest interval in the circumferential direction R, and the two chips 23 adjacent to the convex portion 46 having the arrangement angle α5 have the largest interval in the circumferential direction R. .

  The dimension W in the circumferential direction R (hereinafter, simply referred to as “base thickness W of the convex portion 46”) at the end of each convex portion 46 on the holder main body 47 side (hereinafter sometimes referred to as “the base end portion of the convex portion 46”) Is sometimes set based on the cutting resistance when the chip 23 is cut. Therefore, the base end wall thickness W of each convex part consists of at least two or more different dimensions. The base end wall thickness W of each convex portion 46 is selected so that the base end portion of each convex portion 46 is not damaged during cutting due to cutting resistance during cutting. The convex portion 46 having the arrangement angle α1 has the smallest proximal end thickness W1, but is set to a value at which the proximal end portion of each convex portion 46 is not damaged during cutting. Since the convex portion 46 having the arrangement angle α1 is set so as not to be damaged by the cutting force, the base end wall thicknesses W2, W3, W4 of the convex portions 46 having the arrangement angles α2, α3, α4, α5 larger than the arrangement angle α1. , W5 is set to be larger than the base wall thickness W1 of the convex portion 46 at the arrangement angle α1. Accordingly, by setting so that only the convex portion 46 at the arrangement angle α1 is not damaged, the remaining convex portion 46 is also prevented from being damaged.

  Since the proximal thickness W is set in this way, the shape of each first chip accommodating space forming portion 11 is formed based on the proximal thickness W of each convex portion 46 adjacent to the circumferential direction one R1. Is done. Therefore, since each convex part 46 is formed at different intervals in the circumferential direction R, the shape of the first chip accommodating space 25 of at least one groove is the same as the shape of the first chip accommodating space 25 of the remaining groove 27. Different. Therefore, the interval between the first chip accommodating space forming portions 11 in the circumferential direction R is composed of at least two different intervals. In other words, each of the first chip accommodating space forming portions 11 has a chip mounting state in which the interval in the circumferential direction R1 with the cutting edge 30 of the chip 23 mounted on the convex portion 46 adjacent to the circumferential one R1 is small. Accordingly, the volume of the first chip accommodating space 25 is formed to be small. Therefore, in this Embodiment, the convex part 46 whose arrangement | positioning angle is (alpha) 1 has the smallest 1st chip | tip accommodation space 25, and the convex part 46 which is arrangement | positioning angle (alpha) 5 has the largest 1st chip | tip accommodation space 25. In other words, there are convex portions 46 having a large arrangement angle α and convex portions 46 having a small arrangement angle α, and the convex portion 46 having a large arrangement angle α has a volume of the first chip accommodating space 25 as compared with the convex portions 46 having a small arrangement angle α. large.

Therefore, the relationship between the space | interval P of the circumferential direction R of the convex part 46 and the volume V of the 1st chip | tip accommodating space 25 can be represented, for example by following Formula (1). Here, a is a coefficient of the interval P.
a (P2 / P1) ≈ (V2 / V1) (1)
Thus, the relationship between the shapes of the convex portions 46 is defined by the relationship of Expression (1).

  Specifically, the volume of the first chip accommodating space 25 is the distance H between the surface on the other circumferential direction R2 side of each convex portion 46 and the upper surface 30 of the chip 23, and is the most radially outward Y2 side. It can be changed by adjusting the distance H (hereinafter sometimes simply referred to as “chip space dimension H”). Accordingly, the first chip accommodating space forming part 11 having the arrangement angle α1 has the smallest chip space dimension H1, and sequentially has the chip space dimension H3 and the arrangement angle α2 of the first chip accommodating space forming part 11 having the arrangement angle α3. The chip space dimension H2 of the first chip storage space forming part 11 and the chip space dimension H4 of the first chip storage space forming part 11 having the arrangement angle α4 are large, and the first chip storage space forming part 11 having the arrangement angle α5. The chip space dimension H5 is the largest. Thus, by selecting the chip space dimension H, the volume of the first chip housing space 25 can be defined. In other words, the angle β (hereinafter also referred to as “chip space angle β”) formed between the top surface 30 of the chip 23 and the other circumferential surface R2 of the convex portion 46 is the chip of the convex portion 46 whose arrangement angle is α1. The space angle β1 is the smallest, and in order, the chip space angle β3 of the convex portion 46 having the arrangement angle α3, the chip space angle β2 of the convex portion 46 having the arrangement angle α2, and the chip space angle β4 of the convex portion 46 having the arrangement angle α4. And the chip space angle β5 of the convex portion 46 having the arrangement angle α5 is the largest.

  When designing such a holder 22, first, based on the cutting force calculated from the cutting conditions of the work material, the number of tips 23 to be mounted, and the shape of the tips 23, The end wall thickness W is determined. Next, the arrangement angle α of each chip 23 is determined based on the number of chips 23 to be mounted and the timing at which the cutting resistance that acts on the holder 22 during cutting acts on the holder 22. Next, the volume and shape of the first chip accommodating space 25 are determined based on the arrangement angle α, the base end wall thickness W, and the chip discharging property. That is, the chip space dimension H and the chip space angle β are determined. By designing the holder 22 in this way, damage and regular vibration of the holder 22 can be prevented during cutting, and the chip discharge performance can be improved.

  FIG. 6 is a perspective view showing an example of the chip 23 attached to the holder 22. The chip 23 is generally formed in a plate-like rectangular parallelepiped shape, and the surface in the thickness direction A is formed in a rectangular shape. Of the directions perpendicular to the thickness direction A of the chip 23, a direction extending along the long side of the surface in the thickness direction A is referred to as a longitudinal direction B. Of the directions perpendicular to the thickness direction A of the chip 23, the direction extending along the short side of the surface in the thickness direction A is referred to as the width direction C.

  In the chip mounting state, the other surface in the width direction C of the chip 23 is a first contact surface 51 that contacts the first side surface 41 of the holder. The other surface in the longitudinal direction B of the chip 23 is a second contact surface 52 that contacts the second side surface 42 of the holder 22. Moreover, the surface which becomes thickness direction A one side becomes the upper surface 15 open | released to the 2nd chip accommodation space 25 of the holder 22. FIG. Further, the other surface in the thickness direction A is a bottom surface 39 that comes into contact with the seating surface 40 of the holder 22. At least a part of each of the contact surfaces 51 and 52 and the bottom surface 39 is formed into a flat surface, and substantially contacts the respective side surfaces 41 and 42 and the seating surface 40 of the holder 22 over the entire surface.

  In the state where the contact surfaces 51 and 52 and the bottom surface 39 of the chip 23 are in contact with the side surfaces 41 and 42 and the seating surface 40 of the holder 22, the through hole 50 formed in the chip 23 and the chip accommodation space formation, respectively. The screw hole 29 formed in the portion 24 is coaxial. By screwing a screw member in which an external screw is formed in this state into the through hole 50 and the screw hole 29 of the chip 23, the chip 23 can be fastened to the chip housing space forming portion 24 of the holder 22. 23 can be attached to the chip accommodating space forming part 24 of the holder 22. The chip 23 attached to the holder 22 has a substantially longitudinal direction B extending along the axial direction X of the holder 22, and a width direction C extending substantially along the radial direction Y of the holder 22. The direction A extends along the circumferential direction R of the holder 22.

  The dimension in the thickness direction A of the tip 23 is substantially equal to the dimension in the circumferential direction R of the first side surface 41 and the dimension in the circumferential direction R of the second side surface 42, and the dimension in the longitudinal direction B of the tip 23 is the axis of the seating surface 40. It is set substantially equal to the dimension in the direction X.

  As described above, the holder 22 constituting the end mill 20 of the present embodiment includes the substantially cylindrical holder main body 47 and the convex portion 46 that protrudes radially outward from the holder main body 47 in the radial direction Y2. A plurality of convex portions 46 are formed at different intervals in the circumferential direction R. A chip housing space forming portion 24, a first chip housing space forming portion 11, and a second chip housing space forming portion 10 are formed in a portion between two convex portions 46 adjacent in the circumferential direction R. Therefore, the chip accommodating space forming portions 24 are formed at different intervals in the circumferential direction R. As a result, the timing at which the cutting force acting on the holder 22 acts on the holder 22 can be shifted to suppress the occurrence of regular vibrations. As a result, chatter and resonance based on cutting resistance from the tip 23 to the holder 22 can be suppressed.

  In the chip mounting state, each chip 23 is housed in the chip housing space 26. Since the first chip storage space 25 opens the upper surface of the chip 23 to the outer side Y2 in the radial direction of the holder 22 when the chip is mounted, the chips separated from the work material during cutting are discharged to the outer side Y2 in the radial direction of the holder 22. can do. In addition, since the first chip accommodating space 25 extends along the axial direction X of the holder 22 from a virtual plane including the tip surface of the holder 22, the chips are discharged to the rear end side of the holder 22 along the axial direction X. Can do.

  The dimension in the circumferential direction R at the end of each convex portion 46 on the holder body 47 side, that is, the base end thickness W of each convex portion 46 is set based on the cutting resistance at the time of cutting of the chip 23. Since each convex part 46 is set based on cutting resistance even if the base end wall thicknesses W are different from each other, it can be reliably prevented that the rigidity is locally reduced and damaged. Moreover, the shape of each 1st chip | tip accommodation space formation part 11 is each formed based on the base end thickness W of each convex part 46 adjacent to the circumferential direction one R1. If the shape of each chip accommodating space is the same as in the prior art, the base wall thickness W of the protrusions 46 may be too small and the strength may be reduced when the intervals between the protrusions 46 are different from each other. However, since the shape of the first chip accommodating space forming portion 11 is set based on the base wall thickness W of each convex portion 46 as in the present embodiment, the first chip accommodating space forming portion 11 The shape can be individually set based on the base end wall thickness W of each convex portion 46. By forming the first chip accommodating space forming portion 11 in this way, it is possible to reliably prevent the strength of the convex portion 46 from being lowered. Therefore, since the 1st chip accommodation space 25 can be enlarged as much as possible, a chip can be discharged | emitted smoothly. As a result, damage to the holder 22 can be prevented without impairing chip discharge, and resonance due to the occurrence of regular vibration during cutting can be prevented.

  Moreover, since the 2nd chip accommodation space 12 faces the upper surface 15 of the chip | tip 23 in a chip | tip mounting state, the chip accommodation space of the vicinity of the part which a chip generate | occur | produces can be expanded.

  The second chip storage space 12 is a position away from the front end surface of the holder 22, and the second chip storage space forming part 10 is concave from the first chip storage space forming part 11 toward the circumferential direction one R 1 of the holder 22. Formed by. Therefore, since the front end surface 33a of the holder 22 is the same before and after the second chip housing space forming portion 10 is formed, even if the second chip housing space 12 is formed in the holder, a reduction in rigidity is suppressed. Can do. Since the tip portion 33 of the holder 22 has the largest load at the time of cutting, it is possible to form the second chip accommodating space 12 by suppressing a decrease in rigidity of the portion where the load at the time of cutting is large. Therefore, by forming the second chip accommodating space 12, the holder 22 can be prevented from being damaged during cutting, and the volume of the chip accommodating space can be increased. Therefore, even if the base end wall thickness W of each convex portion 46 is the minimum value based on the cutting resistance, the chip accommodating space can be further expanded by the second chip accommodating space 12, and thus the chip discharging property is further improved. can do.

  In the above-described embodiment, the base end thickness W of each convex portion 46 is not set equal to each other, but may be set equal to each other. In other words, the base end thickness W of each convex portion 46 is a value that does not damage the base end portion of each convex portion 46 during cutting due to cutting resistance during cutting, and may be set to the minimum value thereof. Since the cutting resistance to each convex part 46 at the time of cutting is mutually equal, the damage at the time of cutting can be prevented by setting to the minimum value as mentioned above. Further, by setting the base end wall thickness W of each convex portion 46 to the minimum value, the first chip accommodating space can be made as large as possible. As a result, the strength of the holder 22 can be ensured and the chip discharge performance can be improved.

  Next, the end mill 20 according to the second embodiment of the present invention will be described. In this embodiment, a plurality of types of chips 23 can be mounted, and the axial rake of at least one of the plurality of types of chips 23 is set to be larger than the remaining types of axial rakes. It has a feature in that. The end mill 20 uses a plurality of types of chips 23, for example, two types of chips 23, for example, uses two first chips 23 that are one type of chips 23, and includes second chips 23 that are the other type of chips 23. Three are used. In other words, two types of chips 23 of the first chip 23 that is at least one of the chips 23 and the second chip 23 that is the remaining chip 23 are used. Therefore, for example, the axial rake of the first chip 23 is set larger than the axial rake of the second chip 23. Furthermore, the shape of each 1st chip | tip accommodation space formation part 11 is each formed based on the axial rake of each chip | tip 23. As shown in FIG. Accordingly, each first chip storage space forming unit 11 determines the chip space dimension H and the chip space angle β based on the axial rake of each chip 23. Here, the axial rake is an inclination angle with respect to the axial direction L of the upper surface 15 in a chip mounting state in which the chip 23 is mounted on the holder 22.

  Specifically, the shape of the first chip housing space forming portion 11 is set such that the volume of the first chip housing space 25 increases as the axial rake of each chip 23 increases. Accordingly, the first chip accommodating space 25 corresponding to the first chip 23 is set larger than the first chip accommodating space 25 corresponding to the second chip 23. In other words, there are a convex portion 46 having a large axial rake and a convex portion 46 having a small axial rake, and the convex portion 46 having a large axial rake has a larger volume of the first chip accommodating space than a convex portion having a small axial rake.

  When designing such a holder 22, first, based on the cutting resistance calculated from the cutting conditions of the work material, the number of chips 23 to be mounted, and the axial rake of the chips 23, The proximal thickness W is determined. Next, the arrangement angle α of each chip 23 is determined based on the number of chips 23 to be mounted, the axial rake of each chip 23, and the timing at which the cutting resistance acting on the holder 22 during cutting acts on the holder 22. Is done. Next, the volume and shape of the first chip storage space 25 are determined based on the arrangement angle α, the base wall thickness W, and the chip discharge direction of each chip 23. That is, the chip space dimension H and the chip space angle β are determined. By designing the holder 22 in this way, damage and regular vibration of the holder 22 can be prevented during cutting, and the chip discharge performance can be improved.

  As described above, in the present embodiment, the axial rake of at least one of the plurality of types of chips 23 is set larger than the remaining type of axial rake. As a result, in the state where the tip 23 is mounted, the cutting resistance at the time of cutting differs depending on the axial rake of the tip 23, so that the cutting resistance acting on the holder differs depending on the tip 23. As a result, chatter generated in the holder and resonance due to generation of regular vibration can be suppressed. Therefore, the cutting force acts on the holder irregularly, and the magnitude of the acting cutting force varies depending on the type of the tip 23, so that it is possible to reliably prevent resonance due to the occurrence of regular vibration. Moreover, the shape of each chip accommodation space formation part is each formed based on the axial rake of each chip | tip 23 accommodated in each chip | tip 23 accommodation space formation part. If the axial rake is different, the chip discharge direction during cutting is different, but the shape of the chip storage space forming portion is formed based on the axial rake, so that the chips are smoothly discharged according to the axial rake of each chip 23. Possible chip accommodating space forming portions can be formed. Thereby, chip discharge | emission property can be improved.

  In the present embodiment, the axial rake of each chip 23 is individually set, and the shape of the first chip housing space forming portion 11 is determined based on the axial rake. However, the inclination angle of the seating surface 40 of the holder 22 is determined. Based on γ, the shape of the first chip housing space forming portion 11 may be determined. Thus, even when the same chip 23 is mounted on the holder 22, the angle with respect to the axis L1 of the upper surface 15 of each chip 23 can be set, so that the same operations and effects as in the present embodiment are achieved. be able to.

  Each embodiment as described above is merely an example of the present invention, and the configuration can be changed within the scope of the present invention. For example, although the end mill 20 has been described as a cutting tool, the same effect can be obtained even with other cutting tools, such as a milling milling tool. Further, the shapes of the chip storage space 26, the first chip storage space 25, and the second chip storage space 12 may also be formed other than the shapes described above. Moreover, the holder by the structure of the remainder except the 2nd chip accommodation space formation part 12 may be sufficient.

  In the above-described embodiment, the end mill 20 has the holder 22 and the chip 23 formed separately. However, the end mill 20 is not limited to such a separate structure, and the holder 22 and the chip 23 are integrated. It may be a cutting tool. Such a cutting tool is configured to include a tool body formed in a substantially cylindrical shape and a cutting edge portion having a cutting edge 30 protruding from the outer peripheral surface 32 of the tool body. The tool body has a configuration similar to the holder 22, and the cutting edge portion has a configuration similar to the tip 23. With such a cutting tool, the same operation and effect as the end mill of the above-described embodiment can be achieved.

It is a front view which expands and shows the end mill 20 of the 1st Embodiment of this invention. 2 is a side view showing an end mill 20. FIG. 1 is a perspective view showing an end mill 20. It is a side view which expands and shows the front-end | tip part 33 of the holder 22. FIG. It is a front view which shows the holder 22. FIG. 4 is a perspective view showing an example of a chip 23 attached to a holder 22. FIG. It is a front view which expands and shows the throw away cutter 1 of the 1st prior art. It is a side view which shows the throw away cutter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 2nd chip accommodation space formation part 11 1st chip accommodation space formation part 12 2nd chip accommodation space 15 Upper surface 16 Rear end part 17 Through-hole 20 End mill 22 Holder 23 Throw away tip 24 Chip accommodation space formation part 25 2nd chip accommodation Space 26 Chip receiving space 27 Groove 30 Cutting edge 32 Outer peripheral surface 33a Tip surface 40 Seating surface 46 Convex portion 47 Holder body

Claims (5)

A plurality of plate-shaped chips can be attached and detached, and each chip can be mounted in a chip mounted state in which the cutting edge of the chip protrudes from the outer peripheral surface,
A holder body formed in a substantially cylindrical shape;
One end of the holder axial direction includes a plurality of convex portions that are convex outward from the holder main body in the radial direction of the holder and formed at different intervals in the circumferential direction of the holder,
In a portion between two convex portions adjacent to each other in the holder circumferential direction, a chip housing space forming portion that forms a chip housing space for housing a chip in a chip mounted state;
A chip containing space forming portion is formed which opens the upper surface of the chip radially outward of the holder in a chip mounted state and forms a chip containing space extending from a virtual plane including the tip end surface of the holder along the axial direction of the holder. And
The dimension in the holder circumferential direction at the end of the holder on the holder body side is set based on the cutting resistance at the time of cutting the chip,
The shape of each chip | tip accommodating space formation part is each formed based on the said dimension of each convex part adjacent to one side of a holder circumferential direction.   2. The holder according to claim 1, wherein the dimensions in the circumferential direction of the holder at the end on the holder body side of each of the convex portions are equal to each other. Cutting including a holder that can attach and detach a plurality of plate-shaped tips, and each tip can be attached in a state where the tip cutting edge protrudes from the outer peripheral surface, and a plurality of types of tips that are attached to the holder. A tool,
The axial rake of at least one of the multiple types of chips is larger than the remaining type of axial rake,
The holder is a holder body formed in a substantially cylindrical shape;
One end of the holder axial direction includes a plurality of convex portions that are convex outward from the holder main body in the radial direction of the holder and formed at different intervals in the circumferential direction of the holder,
In a portion between two convex portions adjacent to each other in the holder circumferential direction, a chip housing space forming portion that forms a chip housing space for housing a chip in a chip mounted state;
A chip containing space forming portion is formed which opens the upper surface of the chip radially outward of the holder in a chip mounted state and forms a chip containing space extending from a virtual plane including the tip end surface of the holder along the axial direction of the holder. Cutting tool characterized by being made. A cutting tool including a holder that can attach and detach a plurality of plate-like tips, and each tip can be attached in a state where the tip cutting edge protrudes from the outer peripheral surface, and a plurality of tips that are attached to the holder. There,
The holder is a holder body formed in a substantially cylindrical shape;
One end of the holder axial direction includes a plurality of convex portions that are convex outward from the holder main body in the radial direction of the holder and formed at intervals in the circumferential direction of the holder,
In a portion between two convex portions adjacent to each other in the holder circumferential direction, a chip housing space forming portion that forms a chip housing space for housing a chip in a chip mounted state;
A chip containing space forming portion is formed which opens the upper surface of the chip radially outward of the holder in a chip mounted state and forms a chip containing space extending from a virtual plane including the tip end surface of the holder along the axial direction of the holder. As
The interval between the chips in the holder circumferential direction consists of at least two different intervals,
The cutting tool characterized in that at least two or more different intervals are formed between the chip accommodating space forming portions in the holder circumferential direction.   5. The cutting tool according to claim 4, wherein the dimensions in the holder circumferential direction at the end of each convex portion on the holder body side are equal to each other.

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