JP2010188451A - End mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end mill capable of supplying a sufficient amount of cutting oils without degrading rigidity of an end mill body, lengthening a service life of a tool and also performing cutting work with high machining accuracy. <P>SOLUTION: The end mill has a cutting oil supply path 23 bored to extend from a rear end to a leading end of the end mill body 10 along an axial line O. A plurality of cutting oil distribution paths 24 split from the cutting oil supply path 23 and opening into respective swarf exhausting grooves 14 are also bored. Branches 25 where the cutting oil distribution paths 24 communicate with the cutting oil supply path 23 are provided to stagger in the direction of the axial line O. Percentage of a total ΣS<SB>2</SB>of cross-sectional areas S<SB>2</SB>of the cutting oil distribution paths 24 for a cross-sectional area S<SB>1</SB>of the cutting oil supply path 23 is specified in a range of 50-100%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, a plurality of chip discharge grooves are formed on the outer periphery of the end portion of the end mill body rotated about the axis, and a cutting edge is formed on the outer peripheral side ridge portion of the wall surface facing the end mill rotation direction, and cutting is performed. The present invention relates to an end mill in which a cutting oil supply passage for supplying oil is formed in the end mill body.

  The end mill is generally formed in a columnar shape and a chip discharge groove is formed on the outer periphery of the end portion of the end mill body that is rotated around its axis, and the outer peripheral side ridge portion of the wall surface that faces the front side in the end mill rotation direction of the chip discharge groove The cutting edge is formed on the top edge and the bottom edge connected to the tip of the cutting edge is formed on the side edge of the tip, which is used to cut the workpiece such as grooving and shouldering. It is done. Here, the chip discharge groove is usually formed in a spiral shape twisted around the axis so as to go to the rear side in the end mill rotation direction toward the rear end side of the end mill body, and thus the rotation direction of such a chip discharge groove The cutting edge formed on the outer peripheral side ridge portion of the wall surface facing toward is also formed by being twisted so as to go to the rear side in the rotation direction toward the rear end side of the end mill body.

  Some end mills include an oil hole for supplying cutting oil having a lubricating effect and a cooling effect to the cutting edge in order to reduce friction during cutting and to remove processing heat (for example, Patent Documents). 1, see Patent Document 2). As a result, the tool life can be extended, the machining accuracy can be secured, and good cutting can be performed.

  An example of an end mill having such oil holes is shown in FIG. The oil hole in the end mill branches from the cutting oil supply path 2 formed along the axis O of the end mill body 1 from the rear end side to the front end side of the end mill main body 1 and the cutting oil supply path 2. The end mill main body 1 is composed of a plurality of cutting oil distribution passages 3 that open to a chip discharge groove 4 formed on the outer periphery of the tip portion. The branch portion 5 that is one end of each cutting oil distribution path 3 and communicates with the cutting oil supply path 2 is formed so as to open at the same position in the axis O direction with respect to the peripheral surface of the cutting oil supply path 2. ing.

JP-A-5-253727 JP-A-6-335815

  By the way, since the torsional stress is received by the cutting resistance and the rotational driving force at the time of cutting by the end mill, the end mill main body 1 needs to have rigidity sufficient to withstand this torsional stress. However, in the end mill having the above oil hole, the branching portion 5 is formed so as to open at the same position with respect to the circumferential surface of the cutting oil supply passage 2 in the direction of the axis O. The cross-sectional area of the end mill main body 1 in a vertical cross section is reduced by the presence of each cutting oil distribution path 3, and the rigidity is lowered. As a result, there is a problem that the end mill main body is easily damaged from this position due to torsional stress, the life of the end mill main body 1 is shortened, and the processing cost is increased.

  In addition, since this problem becomes more prominent as the number of cutting oil distribution paths 3 increases, the number of cutting oil distribution paths 3 cannot be increased in order to ensure the rigidity of the end mill body 1. In some cases, sufficient cutting oil cannot be supplied. This also shortens the life of the end mill main body 1 and may reduce the processing accuracy.

  In the above-mentioned end mill, when the total amount of cutting oil that can be circulated through a plurality of cutting oil distribution paths exceeds the amount of cutting oil supplied to the cutting oil supply paths, some cutting oil distribution paths receive cutting oil. I will not be able to spread. On the other hand, if the total amount of cutting oil that can flow through multiple cutting oil distribution paths is too small than the amount of cutting oil supplied to the cutting oil supply path, the pressure loss of the cutting oil in the cutting oil distribution path will increase and chip discharge will occur. A sufficient amount of cutting oil cannot be supplied to the groove. That is, in the conventional end mill, the balance between the cutting oil supply path and the cutting oil distribution path is not considered, and there is a problem in that an appropriate amount of cutting oil cannot be supplied to the cutting location.

  The present invention has been made in view of such a problem, and can supply a sufficient amount of cutting oil while maintaining the rigidity of the end mill main body high, thereby extending the tool life and increasing the machining accuracy. It is an object of the present invention to provide an end mill that can be cut.

In order to solve the above problems, the present invention proposes the following means.
That is, in the end mill according to the present invention, a plurality of chip discharge grooves that spirally twist around the axis are formed on the outer periphery of the end portion of the end mill main body that rotates about the axis, and these chip discharge grooves are forward in the end mill rotation direction. In an end mill in which a cutting edge is formed on the outer peripheral side ridge portion of the wall surface facing the side, a cutting oil supply path extending along the axis is drilled from the rear end side of the end mill body toward the front end side. In addition, a plurality of cutting oil distribution passages that branch off from the cutting oil supply passage and open to the respective chip discharge grooves are formed, and the cutting oil distribution passage and the cutting oil supply passage communicate with each other. The percentage of the total cross-sectional area perpendicular to the extending direction of the cutting oil distribution path with respect to the cross-sectional area perpendicular to the axial line of the cutting oil supply path is 50% to 100%. Range of It is characterized in that it is set to.

According to the end mill having such a configuration, the branch portion that is one end of the cutting oil distribution passage and communicates with the cutting oil supply passage is provided so as to be shifted in the axial direction without overlapping in the axial direction. At the position of the portion, it is possible to suppress a decrease in the cross-sectional area in the cross section perpendicular to the axis line due to the presence of each cutting oil distribution path, and an end mill having a long tool life that is rigid and is not easily damaged. In addition, since the rigidity is ensured in this way, the number of cutting oil distribution paths can be increased, so that more cutting oil can be supplied and the tool life of the end mill can be further extended. In addition, the processing accuracy can be improved.
Here, when the sum of the cross-sectional areas of the plurality of cutting oil distribution paths is larger than the cross-sectional area of the cutting oil supply path, the supply of the cutting oil by the cutting oil supply path does not catch up, and some of the cutting oil distribution paths have a cutting oil supply. Will not spread. On the other hand, if the sum of the cross-sectional areas of the plurality of cutting oil distribution passages is too small than the cross-sectional area of the cutting oil supply passages, the pressure loss of the cutting oil flowing through each of the cutting oil distribution passages will increase, and an appropriate amount of cutting oil will be It cannot be distributed. In this respect, in the end mill of the present invention, since the sum of the cross-sectional areas of the cutting oil distribution passages is 50 to 100% of the cross-sectional area of the cutting oil supply passage, the cutting oil is distributed to each cutting oil distribution passage. In addition, the cutting oil can be smoothly distributed and an appropriate amount of the cutting oil can be supplied to the chip discharge groove.

  Further, in the end mill according to the present invention, when the outer diameter dimension of the cutting edge is D, a virtual cylindrical surface having the outer diameter dimension as a diameter and at least one virtual extension line of the cutting oil distribution path are provided. The intersection is located in a range within 0.3D from the front end to the rear end side of the end mill body.

  If the cutting oil discharged from the cutting oil distribution path does not reach the tip of the end mill main body, it becomes impossible to supply the cutting oil to the cutting portion during shallow groove cutting with a shallow cut. In this regard, in the end mill of the present invention, the cutting oil distribution path is formed so that the cutting oil reaches within the range of 0.3D from the front end portion of the end mill body, that is, from the front end of the end mill body toward the rear end side. Therefore, even in the case of shallow groove machining, sufficient cutting oil can be distributed to the cutting location, and machining accuracy can be improved.

  Furthermore, in the end mill according to the present invention, when the outer diameter dimension of the cutting blade is D, the virtual cylindrical surface having the outer diameter dimension as a diameter and at least one virtual extension line of the cutting oil distribution path The intersection is located in a range of 1.2D or more from the front end to the rear end side of the end mill body.

  If the cutting oil discharged from the cutting oil distribution path does not reach the rear end portion of the cutting edge of the end mill main body, it becomes impossible to supply the cutting oil to the entire cutting location during the standing wall processing with deep cutting. In this respect, in the end mill of the present invention, the cutting oil distribution path is provided so that the cutting oil reaches the rear end of the cutting edge, that is, the range of 1.2D or more from the front end of the end mill body toward the rear end. Since it is formed, sufficient cutting oil can be spread over the entire cutting location even in the case of standing wall machining, and machining accuracy can be improved.

  The end mill according to the present invention is characterized in that a plurality of the cutting oil distribution passages are opened in each of the chip discharge grooves.

  Since the reduction in rigidity of the end mill body due to the presence of the cutting oil distribution path is suppressed, sufficient rigidity can be secured even if multiple cutting oil distribution paths are provided in the chip discharge groove, and more cutting oil is supplied. It becomes possible to do.

  Further, in the end mill according to the present invention, the intersection of the virtual cylindrical surface having the lead length of the cutting edge as L, the outer diameter dimension as D, and the outer diameter dimension D as a diameter and the virtual extension line of the cutting oil distribution passage. When the interval in the axial direction is b, the interval a in the circumferential direction of the intersection on the virtual cylindrical surface is set to a = πD × (b / L).

  By providing a plurality of cutting oil supply passages in this way, the distance in the cross section perpendicular to the axis of each of the openings in the chip discharge groove of the cutting oil supply passage and the cutting blade can be made constant. It becomes possible to supply cutting oil effectively in the whole area.

  Further, in the end mill according to the present invention, at least two of the plurality of chip discharge grooves have the cutting oil distribution passage in which the branch portion is provided shifted in the axial direction, and the position in the axial direction is the same. It may be opened so as to be.

As a result, while ensuring the rigidity in the vicinity of the cutting oil supply passage as described above, the supply distribution of the cutting oil of the cutting blades facing in the circumferential direction can be made the same. In the same manner, uniform cutting can be performed.
Further, for example, in an end mill having three or more blades, only the cutting oil distribution passages in at least two chip discharge grooves are opened so that the positions in the axial direction are the same. By making the supply distribution of cutting oil the same as other chip discharge grooves, but avoiding the cutting oil distribution path from concentrating and opening at the same position in the axial direction, the rigidity at the outer periphery of the end mill body is more than necessary. It can prevent that it falls.

  According to the end mill of the present invention, the branch portion of the oil hole is provided by shifting in the axial direction without overlapping in the axial direction, and by adjusting the ratio of the cross-sectional areas of the cutting oil supply passage and the cutting oil distribution passage. A sufficient amount of cutting oil can be supplied while maintaining the rigidity of the end mill body. Therefore, it is possible to extend the tool life of the end mill and improve the machining accuracy.

It is the side view which fractured a part of end mill concerning a first embodiment. It is front sectional drawing which shows arrangement | positioning of the oil hole of the end mill which concerns on 1st embodiment. It is a longitudinal cross-sectional view which shows arrangement | positioning of the oil hole of the end mill which concerns on 1st embodiment. It is an expanded view of the shank part and virtual cylindrical surface of an end mill main body in 1st embodiment. It is a side view of a 6 blade end mill which is a modification of the first embodiment. It is a longitudinal cross-sectional view which shows arrangement | positioning of the oil hole of the end mill which concerns on 2nd embodiment. It is an expanded view of the shank part and virtual cylindrical surface of an end mill main body in 2nd embodiment. It is an expanded view of the shank part and virtual cylindrical surface of the end mill main body of 4 blades which is a modification of 2nd embodiment. It is an expanded view of the shank part and virtual cylindrical surface of the end mill main body of 6 blades which is a modification of 2nd embodiment. It is a side view of the conventional end mill.

  Hereinafter, a first embodiment of an end mill according to the present invention will be described with reference to FIGS. 1 to 4. 1 is a side view in which a part of an end mill according to the first embodiment is broken, FIG. 2 is a front sectional view showing the arrangement of oil holes of the end mill according to the first embodiment, and FIG. 3 is a first embodiment. FIG. 4 is a development view of the shank portion and the virtual cylindrical surface of the end mill main body according to the first embodiment.

  In the first embodiment, as shown in FIGS. 1 and 2, the end mill main body 10 is formed of a hard material such as a cemented carbide and is formed integrally with a hard material so as to be centered on the axis O and extend along the axis O. The rear end portion (right side portion in FIG. 1) is a shank portion 12, and the tip end portion (left side portion in FIG. 1) is a cutting edge portion 13. A plurality of (two in the present embodiment) circumferential direction of chip discharge grooves 14 spirally twisted toward the rear side in the end mill rotation direction T when cutting about the axis O from the front end to the rear end side of the end mill body 10. Are formed at equal intervals.

  The wall surface 15 of the chip discharge groove 14 facing the front side in the end mill rotation direction T is formed in a concave curved surface in a cross section orthogonal to the axis O as shown in FIG. A cutting edge 17 that is spirally twisted at the same twist angle as that of the chip discharge groove 14 is formed at the intersecting ridge line portion with the outer peripheral surface 16 of the cutting edge portion 13, and thus the wall surface 15 is a rake of the cutting edge 17. It is considered a surface.

  Further, on the outer peripheral surface 16, in order from the cutting edge 17 toward the rear side in the end mill rotation direction T, a flank 18 connected to the cutting edge 17, a flank 18 connected to the flank 18, and a clearance angle and An outer peripheral flank 19 having a large circumferential width is formed. In addition, a margin that extends from the cutting edge 17 to the rear side in the end mill rotation direction T may be provided. In addition, the outer peripheral surface 16 on the rear side in the end mill rotational direction T from the outer peripheral flank 19 retreats one step toward the inner peripheral side with respect to the outer peripheral flank 19 and then draws a convex curved surface toward the rear side in the end mill rotational direction T. Further, it is formed so as to continue to the wall surface 15 which is the rake face of the cutting blade 17 through the chip discharge groove 14.

  On the other hand, as shown in FIG. 1, a gash 20 is formed at the tip of the chip discharge groove 14. The gasche 20 is a recess formed so as to radially cut out the tip edge of the wall surface 15 of the chip discharge groove 14 from the center of the tip of the end mill body 10 to the outer peripheral flank 9 on the outer periphery of the tip. In this embodiment, the wall surface facing the end mill rotation direction T is a planar gash surface 11 that is substantially parallel to the axis O. A bottom blade 21 is formed at the intersecting ridge line portion between the gash surface 11 and the tip flank 12 formed at the tip of the end mill body 10 so as to continue to the tip of the cutting blade 17.

  The end mill body 10 has a cutting oil supply passage 23 formed therein and supplied with cutting oil, and a plurality of branches extending from the cutting oil supply passage 23 and extending linearly and opening into the chip discharge groove 14. An oil hole 22 including a cutting oil distribution path 24 is formed.

  The cutting oil supply path 23 is formed as a bottomed hole that extends along the axis O toward the front end side while opening to the rear end side of the shank portion 12. In the present embodiment, the shape of the cutting oil supply path 23 is formed as a circular cross section having a constant diameter centered on the axis O over the entire length, and the inner diameter is the outer diameter, thickness, etc. of the end mill body 10. Can be set in consideration.

  On the other hand, each cutting oil distribution path 24 opens to the inner peripheral surface of the cutting oil supply path 23 as a branching portion 25 that communicates with the cutting oil supply path 23 on one end side of the inner periphery, and the chip discharge groove 14 on the other end side. A discharge port 26 is formed by opening the bottom surface of the groove portion toward the cutting edge. In the present embodiment, the cutting oil distribution path 24 is formed so that two discharge ports 26 are opened to the two chip discharge grooves 14, that is, four are branched from the cutting oil supply path 23. ing.

  These cutting oil distribution passages 24 are formed in a circular cross section having a constant diameter from the branching portion 25 to the discharge port 26, and more specifically, as shown in FIG. As it goes to the outer peripheral side, it is inclined so as to extend linearly toward the tip side. And the branch part 25 of each cutting-oil distribution path 24 is shifted and provided so that the position of the axis line O direction may not mutually overlap. In addition, it is preferable that the inclination | tilt angle with respect to the axis line O of each cutting oil distribution path 24 is set to the range of 40 degrees-60 degrees.

  Note that the cutting oil distribution path 24 is not limited to the one that is inclined so as to extend toward the tool tip side toward the outer peripheral side as described above, but extends vertically from the cutting oil supply path 23 toward the outer peripheral side. There may be.

Further, the inner diameters of the cutting oil supply path 23 and the cutting oil distribution path 24 are set so as to satisfy the following relationship. That is, in this embodiment, when the cross-sectional area perpendicular to the axis O of the cutting oil supply passage 23 is S ₁ and the cross-sectional area perpendicular to the extending direction of the cutting oil distribution passage 24 is S ₂ , a plurality of (this embodiment) The sum ΣS ₂ of the cross-sectional areas S ₂ of the four cutting oil distribution passages 24 satisfies the relationship of 0.5 × S ₁ ≦ ΣS ₂ ≦ S ₁ .
In other words, the percentage of the sum [sigma] s ₂ of the sectional area _{S 2} of the cutting oil distribution passage 24 to the cross-sectional area _{S 1} of the cutting oil supply path 23, so that the range of 50% to 100%, cutting oil feed passage 23 and cutting The value of the inner diameter of the oil distribution path 24 is determined.

  Further, as shown in detail in FIGS. 2 and 4, the arrangement of the discharge ports 26 that are openings of the respective cutting oil distribution paths 24 is such that the chip discharge grooves 14 and the cutting blades 17 that are twisted in a spiral shape are arranged around the axis O. A virtual cylindrical surface P and a cutting oil distribution path 24 having a lead length which is a length in the direction of the axis O during one round as L, an outer diameter dimension of the cutting edge 17 as D, and an outer diameter dimension of the cutting edge 17 as a diameter. When an interval R (corresponding to the discharge port 26) of the intersection R with the virtual extension line Q in the direction of the axis O is b, the circumferential interval a on the virtual cylindrical surface P of the intersection R is a = πD × ( b / L). Thereby, the distance of the circumferential direction in the cross section perpendicular | vertical to the axis line O of the two discharge ports 26 and the cutting blade 17 in each chip discharge groove 14 is made constant.

  Furthermore, at least one of the cutting oil distribution passages 24 has an intersection R between the virtual extension line Q and the virtual cylindrical surface P whose diameter is the outer diameter of the cutting edge 17 from the front end of the end mill body 10 to the rear end side. As shown in FIG. 4, it is formed so as to be located in a range within 0.5D.

  Furthermore, at least one of the cutting oil distribution passages 24 is such that the intersection R between the virtual extension line Q of the cutting oil distribution passage 24 and the virtual cylindrical surface P whose diameter is the outer diameter of the cutting edge 17 is the end mill body. It is formed so as to be located in a range of 1.0 D or more, preferably in a range of 1.2 D or more as shown in FIG.

  In the end mill configured as described above, the shank portion 12 formed at the rear end of the end mill body 10 is gripped by the spindle end of the machine tool, rotated around the axis O, and in a direction intersecting the axis O. Is sent to the workpiece to groove it. At this time, the cutting oil is supplied to the outer peripheral surface 16 of the chip discharge groove 14 via the cutting oil supply path 23 and the cutting oil distribution path 24, and reaches the cutting edge 17. Reduces friction with the machine and removes processing heat.

  During cutting with such an end mill, the end mill body 10 needs to have rigidity sufficient to withstand this torsional stress because it receives a torsional stress due to cutting resistance and rotational driving force. According to the end mill having the above-described configuration, the branch portion 25 in the oil hole 22 is provided so as to be shifted in the axis O direction without overlapping in the axis O direction. The reduction of the cross-sectional area in the cross section perpendicular to the cross section can be suppressed, the rigidity of the end mill body 10 is ensured, and the life of the end mill body 10 can be extended.

  In addition, since the rigidity is ensured in this way, the number of the cutting oil distribution passages 24 can be increased. Therefore, a plurality (two in this embodiment) are provided for each chip discharge groove 14 as in the present embodiment. The strength of the end mill body 10 can be maintained even if the cutting oil distribution passage 24 is formed so as to open. Therefore, more cutting oil can be supplied, and the tool life of the end mill can be further extended by the lubricating effect and cooling effect of the cutting oil, and the machining accuracy can be improved.

Here, when the sum ΣS ₂ of the cross-sectional areas S ₂ of the plurality of cutting oil distribution passages 24 is larger than the cross-sectional area S _{1 of} the cutting oil supply passages 23, cutting is performed more than the amount of cutting oil flowing through the cutting oil supply passages 23. Since the total amount of cutting oil that can flow through the oil supply path 23 is greater, the cutting oil supply by the cutting oil supply path 23 cannot catch up, and the cutting oil does not reach the part of the cutting oil distribution paths 24. .
On the other hand, if the sum [sigma] s ₂ cross-sectional area S2 of the plurality of cutting oil distribution passage 24 is too small than the cross-sectional area S ₁ of the cutting oil supply passage 23, if [sigma] s ₂ is less than 50% of S ₁ specifically The pressure loss of the cutting oil that passes through the respective cutting oil distribution passages 24 increases, and a sufficient amount of cutting oil cannot be circulated.
In this respect, in the present embodiment, the sum ΣS ₂ of the cross-sectional area S ₂ of the cutting oil distribution path 24 is 50 to 100% of the cross-sectional area S 1 of the cutting oil supply path 23. In addition, the cutting oil can be distributed to each other, and a sufficient amount of the cutting oil can be supplied to the chip discharge groove by smoothly circulating the cutting oil in each cutting oil distribution passage 24.

  Further, when the cutting oil discharged from the discharge port 26 of the cutting oil distribution path 24 does not reach the tip of the end mill main body 10, in the shallow groove processing with a shallow notch, the tip of the end mill main body 10, which is a cutting point, is formed. It becomes impossible to supply cutting oil. In this respect, in the end mill of the present embodiment, at least one of the cutting oil distribution passages 24 has an intersection R between the virtual extension line Q and the virtual cylindrical surface P having a diameter of the cutting edge 17 at the rear of the end mill body 10. Since it is formed so as to be located in a range within 0.5D toward the end side, preferably in a range within 0.3D, the cutting oil discharged from the cutting oil distribution path 24 is the tip of the end mill body 10. To reach. Therefore, even in the case of shallow groove machining, sufficient cutting oil can be distributed to the cutting location, and machining accuracy can be improved.

  Further, when the cutting oil discharged from the discharge port 26 of the cutting oil distribution path 24 does not reach the rear end portion of the cutting edge 17 of the end mill main body 10, the cutting oil is supplied to the entire cutting portion during the standing wall processing with a deep cut. You will not be able to. In this respect, in the end mill of the present embodiment, at least one of the cutting oil distribution passages 24 has an intersection R between the virtual extension line Q and the virtual cylindrical surface P having a diameter of the cutting edge 17 at the rear of the end mill body 10. Since it is formed so as to be located in the range of 1.0D or more, preferably in the range of 1.2D or more toward the end side, the cutting oil discharged from the cutting oil distribution passage 24 is directed to the rear end portion of 17. To reach. Therefore, even in the case of standing wall machining, sufficient cutting oil can be spread over the entire cutting location, and machining accuracy can be improved.

  Furthermore, in the end mill according to the present embodiment, the circumferential distance in the cross section perpendicular to the axis O between the two discharge ports 26 and the cutting blade 17 in each chip discharge groove 14 is constant. It becomes possible to supply cutting oil effectively in the whole area of 17, and the lubricating effect and cooling effect by the cutting oil can be obtained more effectively.

As described above, according to the end mill of the present embodiment, the branch portion 25 in the oil hole 22 is provided so as to be shifted in the direction of the axis O without overlapping with the direction of the axis O, and the cross-sectional area S ₁ of the cutting oil supply passage 23 and the cutting By adjusting the ratio of the total sum ΣS ₂ of the cross-sectional area S ₂ of the oil distribution path 24 and setting the respective diameters, a sufficient amount of cutting oil can be supplied without reducing the rigidity of the end mill body 10. it can. Therefore, it is possible to extend the tool life of the end mill and perform cutting with high processing accuracy.

In the end mill, two chip discharge grooves 14 are formed on the outer periphery of the end portion of the end mill main body 10, and a cutting edge is formed on the outer side edge of the wall surface facing the front side in the end mill rotation direction T of the chip discharge grooves 14. In the two-blade end mill in which 17 is formed, two cutting oil discharge ports 26 are provided for one chip discharge groove 14, but the present invention is not limited to this. For example, FIG. The present invention may be applied to a six-blade end mill 30 as in the modification shown, and three or more cutting oil discharge ports 26 may be provided for one chip discharge groove 14. Also in this case, a branch portion (not shown) that is one end of a cutting oil distribution (not shown) that communicates with the discharge port 26 and communicates with the cutting oil supply passage 23 is shifted in the direction of the axis O without overlapping in the direction of the axis O. Furthermore, since the percentage of the sum ΣS ₂ of the cross-sectional area S ₂ of the cutting oil distribution path 24 with respect to the cross-sectional area S ₁ of the cutting oil supply path 23 is set in the range of 50% to 100%, the rigidity of the end mill It is possible to supply a sufficient amount of cutting oil while ensuring the above.

  Next, a second embodiment of the end mill according to the present invention will be described with reference to FIGS. FIG. 6 is a longitudinal sectional view showing the arrangement of the oil holes of the end mill according to the second embodiment, and FIG. 7 is a development view of the shank portion and the virtual cylindrical surface of the end mill body of the second embodiment.

The end mill of this embodiment is a two-blade end mill similar to that of the first embodiment, and the discharge ports 26 in the chip discharge grooves 14 facing in the circumferential direction are on the same circumference around the axis O. It is different from the first embodiment in that it is arranged, and the other configuration is the same as that of the first embodiment.
6 and 7 showing the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 6, a total of three cutting oil distribution paths 28 in the second embodiment are formed with respect to one chip discharge groove 14, and those that open to the same chip discharge groove 14. Are linearly extended at the same inclination angle with respect to the axis O. On the other hand, when the openings in the chip discharge grooves 14 facing each other in the circumferential direction are compared, the inclination angles with respect to the axis O are different from each other. As a result, the branch portion 25 communicating with the cutting oil supply passage 23 is disposed so that the positions in the direction of the axis O do not overlap with each other, while the discharge port 26 in the chip discharge groove 14 is formed as shown in FIGS. As shown in FIG. 5, the chip discharge grooves 14 facing each other are arranged so as to be located on the same circumference around the axis O, that is, in the same direction in the direction of the axis O.
In addition, the inclination angle with respect to the axis O of the plurality of cutting oil distribution passages 28 is set within a range of 40 ° to 60 °. Further, as in the first embodiment, the percentage of the sum ΣS ₂ of the cross-sectional area S ₂ of the cutting oil distribution path 24 with respect to the cross-sectional area S ₁ of the cutting oil supply path 23 is in the range of 50% to 100%. Further, the values of the diameters of the cutting oil supply path 23 and the cutting oil distribution path 24 are set.

Also in the present embodiment, as in the first embodiment, the arrangement of the discharge ports 26 that are the openings of the respective cutting oil distribution passages 28 is such that the lead length is L and the cutting edge 17 is arranged as shown in FIG. The distance in the direction of the axis O between the intersection R (corresponding to the discharge port 26) of the virtual cylindrical surface P having the outer diameter dimension D and the outer diameter dimension of the cutting edge 17 and the virtual extension line Q of the cutting oil distribution path 28. Is set so that the interval a in the circumferential direction on the virtual cylindrical surface P of the intersection R is a = πD × (b / L).
Thereby, the distance of the circumferential direction in the cross section perpendicular | vertical to the axis O of the two discharge ports 26 and the cutting blade 17 in each chip discharge groove 14 is made constant. Further, in the present embodiment, unlike the first embodiment, the intersection R in the facing chip discharge groove 14 is also arranged on the same circumference around the axis O in accordance with the arrangement of the discharge ports 26.

Further, also in the end mill of the present embodiment, at least one of the cutting oil distribution passages 24 is such that the intersection R between the virtual extension line Q and the virtual cylindrical surface P whose diameter is the outer diameter of the cutting edge 17 is the end mill body. It is formed so as to be located in a range within 0.5D from the front end of 10 toward the rear end side, preferably within a range within 0.3D as shown in FIG.
Furthermore, at least one of the cutting oil distribution passages 24 has an intersection R between the virtual extension line Q and the virtual cylindrical surface P whose diameter is the outer diameter of the cutting edge 17 from the front end of the end mill body 10 to the rear end side. It is formed so as to be located in a range of 1.0D or more, preferably 1.2D or more as shown in FIG.

  According to the end mill of the second embodiment configured as described above, a sufficient amount of cutting oil can be supplied while ensuring the rigidity in the vicinity of the cutting oil supply passage 23 as in the end mill of the first embodiment. In addition, since the discharge ports 26 in the two chip discharge grooves 14 are located on the same circumference with the axis O as the center, the supply distribution of the cutting oil to each chip discharge groove 14 should be the same. Can do. Therefore, uniform cutting can be performed with the same lubricating effect and cooling effect for each of the cutting edges 17 formed on the outer peripheral side ridges of the chip discharge grooves 14.

  The end mill according to the second embodiment is not limited to the two-blade end mill shown in FIGS. 6 and 7, and may be a four-blade end mill as shown in a development view of FIG. 8 as a modification. This end mill has four chip discharge grooves 14, and three cutting oil distribution paths 24 are formed for one chip discharge groove 14. Of the four chip discharge grooves 14, the discharge ports 26 in the pair of chip discharge grooves 14 facing in the circumferential direction (at the intersection R between the virtual cylindrical surface P and the virtual extension line Q of the cutting oil distribution path 24 in FIG. 8). Corresponding) are arranged on the same circumference around the axis O, that is, the positions in the direction of the axis O are the same, and are discharged in a pair (a pair) of chip discharge grooves 14 facing in the other circumferential directions. The outlets 26 are disposed at the same position at different positions in the axis O direction.

  Thereby, in the chip discharge grooves 14 opposed in the circumferential direction, the same lubrication effect and cooling effect can be obtained by making the supply distribution of the cutting oil the same, while in the chip discharge grooves 14 adjacent in the circumferential direction, Since the position of the discharge port 26 is shifted and dispersed in the direction of the axis O, it is possible to prevent the rigidity of the outer periphery of the end mill body 10 from being lowered more than necessary.

  Further, the end mill of the second embodiment may be a six-blade end mill as shown in the development view of FIG. This end mill has six chip discharge grooves, and two cutting oil distribution passages 24 are formed for one chip discharge groove 14. The discharge ports 26 in the pair of chip discharge grooves 14 facing each other in the circumferential direction are arranged on the same circumference around the axis O, that is, the positions in the axis O direction are the same. This also makes it possible to make the supply distribution of the cutting oil the same as described above, and to prevent the rigidity of the outer periphery of the end mill body 10 from being lowered more than necessary.

Note that these also in the second end mill 4 flute and six blades which is a modification of the embodiment, the total cross-sectional area S ₂ of the cutting oil distribution passage 24 to the cross-sectional area S ₁ of the cutting oil supply passage 23 [sigma] s ₂ Since the values of the diameters of the cutting oil supply passage 23 and the cutting oil distribution passage 24 are set so that the percentage of the oil is in the range of 50% to 100%, a sufficient amount of cutting oil is ensured while ensuring the rigidity of the end mill. Can be supplied. Further, as shown in FIGS. 8 and 9, also in the four-blade and six-blade end mills, at least one of the cutting oil distribution paths 24 includes a virtual extension line Q of the cutting oil distribution path 24 and a cutting edge. The intersection R with the virtual cylindrical surface P having an outer diameter of 17 as a diameter is located within a range within 0.5D, preferably within a range within 0.3D from the front end of the end mill body 10 toward the rear end. Is formed. Further, at least one of the cutting oil distribution passages 24 has an intersection R between a virtual extension line Q of the cutting oil distribution passage 24 and a virtual cylindrical surface P having an outer diameter dimension of the cutting edge 17 as a diameter of the end mill body 10. It is formed so as to be located in a range of 1.0D or more, preferably 1.2D or more from the front end toward the rear end side. Therefore, even in the case of shallow groove machining or standing wall machining, sufficient cutting oil can be spread over the entire cutting location, and machining accuracy can be improved.

As mentioned above, although the embodiment of the end mill which is this invention was described in detail, unless it deviates from the technical idea of this invention, it is not limited to these, A some design change etc. are possible.
For example, the two-blade and six-blade end mills are shown in the first embodiment, and the two-blade, four-blade and six-blade end mills are shown in the second embodiment. In both embodiments, an end mill having a number of cutting blades 17 other than the above may be used.

  In the above embodiment, the end mill in which the plurality of chip discharge grooves 14 and the cutting edges 17 are twisted at the same twist angle has been described. However, the present invention is not limited to this, and the twist of the chip discharge grooves 14 and the cutting edges 17 is not limited thereto. A so-called unequal lead end mill with different corners may be used. In this case, the arrangement of the discharge ports 26 that are openings of the respective cutting oil distribution paths 24 is such that the virtual length of the intersection R between the virtual cylindrical surface P and the virtual extension line Q with respect to the lead length L of any one of the cutting edges 17. It is only necessary that the circumferential interval a on the cylindrical surface P be a = πD × (b / L).

DESCRIPTION OF SYMBOLS 10 End mill main body 14 Chip discharge groove 15 Wall surface 17 Cutting edge 23 Cutting oil supply path 24 Cutting oil distribution path 25 Branch part 26 Discharge port 28 Cutting oil distribution path O Axis line P Virtual cylindrical surface Q Virtual extension line R Virtual cylindrical surface and virtual extension Intersection with line S ₁ Cross-sectional area of cutting oil supply path S ₂ Cross-sectional area of cutting oil distribution path T End mill rotation direction

Claims (6)

A plurality of chip discharge grooves spirally twisted around the axis are formed on the outer periphery of the end portion of the end mill body rotated around the axis, and the outer peripheral side ridges of the wall surface facing the front side in the end mill rotation direction of these chip discharge grooves In the end mill where the cutting edge is formed in the part,
A cutting oil supply path extending along the axis is drilled from the rear end side to the front end side of the end mill body, and branches from the cutting oil supply path and extends to each chip discharge groove. A plurality of cutting oil distribution passages are opened,
A branch portion where the cutting oil distribution path and the cutting oil supply path communicate with each other is provided shifted in the axial direction,
The percentage of the sum total of the cross-sectional areas perpendicular to the extending direction of the cutting oil distribution path with respect to the cross-sectional area perpendicular to the axis of the cutting oil supply path is set in a range of 50% to 100%. End mill. When the outer diameter of the cutting edge is D,
An intersection of a virtual cylindrical surface having the outer diameter dimension as a diameter and at least one virtual extension line of the cutting oil distribution path is located within a range of 0.3D from the front end of the end mill body toward the rear end. The end mill according to claim 1, wherein the end mill is provided. When the outer diameter of the cutting edge is D,
The intersection of the virtual cylindrical surface having the outer diameter as a diameter and at least one virtual extension line of the cutting oil distribution path is located in a range of 1.2 D or more from the front end of the end mill body toward the rear end. The end mill according to claim 1, wherein the end mill is provided.   The end mill according to any one of claims 1 to 3, wherein a plurality of the cutting oil distribution passages are opened in each of the chip discharge grooves. The lead length of the cutting edge is L, the outer diameter dimension is D, and the axial distance between the intersections of the virtual cylindrical surface having the outer diameter dimension as a diameter and the virtual extension line of the cutting oil distribution path is b. When
The end mill according to any one of claims 1 to 4, wherein an interval a in the circumferential direction of the intersection on the virtual cylindrical surface is set to a = πD x (b / L).   In at least two of the plurality of chip discharge grooves, the cutting oil distribution path provided with the branch portions shifted in the axial direction is opened so that the positions in the axial direction are the same. The end mill according to any one of claims 1 to 5, characterized in that:

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