JP5776595B2 - End mill with coolant hole - Google Patents

Description

  In the present invention, a long bottom blade extending beyond the axis of the end mill body from the outer periphery toward the inner peripheral side and a short bottom blade having an inner peripheral end at a position away from the axis are formed at the distal end portion of the end mill body. The present invention relates to an end mill with a coolant hole in which a coolant hole is formed in the end mill body.

  As such an end mill with a coolant hole, for example, in Patent Document 1, a pair of long bottom blades provided near the axis along a pair of first gashes formed symmetrically with respect to the axis, A pair of short holes provided along a second gash formed so as to reach the first gash from the outer periphery symmetrically with respect to the axial center at a position 90 ° from the pair of long bottom blades around the center. A fluid supply hole (coolant hole) provided through the end mill with a pair of openings that open to the flank of the pair of long bottom blades, and an end on the axial center side. A communication area of the first and second gashes that intersect each other is increased, and a pair of communication grooves provided to connect the intersecting portion of the first and second gashes with the opening of the coolant hole. Have Four unequal bottom edge of the end mill with Zealand hole is described.

Japanese Patent No. 4409665

  By the way, in the end mill with a coolant hole described in Patent Document 1, the coolant supplied from the openings of the pair of coolant holes is supplied to the first and second of the long bottom blade and the short bottom blade via the pair of communication grooves. Since the gas is supplied to the gash, if more coolant is to be supplied, the coolant hole, its opening, and the communication groove must be enlarged. However, the coolant hole has a pair of openings on the tip flank of the long bottom blade as described above, and the communication groove is connected from this opening to the intersection of the first and second gashes, If the coolant hole, its opening, and the communication groove are enlarged, it is inevitable that the tip flank of the long bottom blade will be greatly cut out.

  However, as described in Patent Document 1, in an end mill with a coolant hole in which a pair of short bottom blades is formed at a position of 90 ° from the pair of long bottom blades, the tip flank surfaces of the long bottom blade and the short bottom blade are Although the size can be substantially the same, in order to prevent chatter vibration, the distance between the long bottom blade and the short bottom blade adjacent to the front side in the end mill rotation direction is the front of the short bottom blade and the end mill rotation direction. In an end mill that is larger than the distance between the long bottom blade adjacent to the side, the tip flank of the long bottom blade must be smaller than the tip flank of the short bottom blade.

  However, in such an end mill, if the tip flank of the long bottom blade is greatly cut out in this way, the wall thickness of the end mill body on the rear side in the end mill rotation direction of the long bottom blade is scraped and the cutting edge of the long bottom blade is cut. Strength will be lost. In addition, the long bottom blade is longer than the short bottom blade, and the distance between the short bottom blade on the front side in the end mill rotation direction is larger than the distance between the short bottom blade and the long bottom blade adjacent to the front side in the end mill rotation direction. Therefore, if the cutting edge strength is impaired in such a long bottom blade, damage such as chipping is likely to occur.

  The present invention has been made under such a background, and the interval between the long bottom blade and the short bottom blade adjacent to the front side in the end mill rotation direction is adjacent to the short bottom blade and the front side in the end mill rotation direction. It is an object of the present invention to provide an end mill with a coolant hole capable of supplying sufficient coolant without impairing the cutting edge strength of the long bottom blade in the end mill having a larger distance from the long bottom blade.

  In order to solve the above-described problems and achieve such an object, the present invention is directed to the end portion of the end mill body rotated about the axis line so as to cross the axis line from the outer periphery to the inner periphery side of the end mill body. Long bottom blades and short bottom blades having inner peripheral ends at positions away from the axis are alternately formed in the circumferential direction, and the long bottom blades and short bottom blades adjacent to the front side in the end mill rotation direction Is larger than the interval between the short bottom blade and the long bottom blade adjacent to the front side in the end mill rotation direction, and a plurality of coolant holes are formed in the end mill body. Among these, the first coolant hole is opened in a gash formed on the front side in the end mill rotation direction of the long bottom blade, and the second coolant hole is opened in the tip flank of the short bottom blade. And wherein the door.

  In the end mill with the coolant hole thus configured, first, the first and second coolant holes among the plurality of coolant holes formed in the end mill body with respect to the pair of long bottom blades and short bottom blades. Is opened, more coolant can be supplied. The first coolant hole is at least partially opened in the gash of the long bottom blade, and the second coolant hole is opened in the tip flank of the short bottom blade, so that the long bottom blade and its end mill rotate. The distance between the short bottom blade adjacent to the front side in the direction is larger than the distance between the short bottom blade and the long bottom blade adjacent to the front side in the end mill rotation direction, and the tip flank of the long bottom blade is the short bottom blade. Even if it is made smaller than the tip flank, it can be avoided that a coolant hole is opened in the tip flank of this long bottom blade.

  Therefore, the thickness of the end mill body on the rear side in the end mill rotation direction of the long bottom blade can be prevented from being scraped, the cutting edge strength of the long bottom blade can be secured, and the long bottom blade can be damaged during cutting. Can be prevented. On the other hand, since the tip flank of the short bottom blade can be made larger than the long bottom blade, the cutting edge strength of the short bottom blade can be maintained even if the second coolant hole is opened. It is possible to prevent defects and the like from occurring.

  In addition, since the tip flank of the short bottom blade can be increased in this way, the second coolant hole has a larger opening area than the first coolant hole, thereby preventing the short and short bottom blade from being damaged. It becomes possible to supply more coolant. Furthermore, by opening the first coolant hole on the radially inner peripheral side with respect to the axis than the second coolant hole, the first coolant hole is moved from the inner peripheral side in the vicinity of the axis of the long bottom blade extending beyond the axis to the outer peripheral side. Thus, the coolant can be supplied evenly, and the chips generated by the long bottom blade can be reliably discharged.

  As described above, according to the present invention, it becomes possible to supply more coolant without impairing the cutting edge strength of the long bottom blade or the short bottom blade, and damage such as a defect occurs in the long and short bottom blade. It is possible to prevent the wear of the bottom blade and its tip flank, and to promote efficient chip discharge while ensuring reliable cooling and lubrication of the cutting parts of these long and short bottom blades and work materials. Become.

It is a perspective view which shows one Embodiment of this invention. It is a side view of embodiment shown in FIG. It is an enlarged front view of embodiment shown in FIG.

  1 to 3 show an embodiment of the present invention. In the present embodiment, the end mill body 1 is integrally formed of a hard material such as cemented carbide in a substantially cylindrical shaft shape with the axis O as the center, and a rear end portion (upper right side portion in FIG. 1; FIG. 2). The upper part) is a cylindrical shank part 2 and the tip part (the lower left part in FIG. 1, the lower part in FIG. 2) is the cutting edge part 3. In such an end mill, the shank portion 2 is gripped by the main spindle of the machine tool, and is rotated in the end mill rotation direction T around the axis O, and is usually fed in a direction crossing the axis O, and is cut by the cutting edge portion 3. Cutting material.

  Around the outer periphery of the cutting edge 3 at the tip of the end mill body 1, there are four chip discharge grooves 4 that twist about the axis O toward the rear side in the end mill rotation direction T from the leading edge of the cutting edge 3 toward the rear edge. It is formed at intervals in the direction. At the outer peripheral side ridge portion of the wall surface of the chip discharge groove 4 facing the end mill rotation direction T, the end mill rotates about the axis O as it goes from the front end to the rear end side of the cutting blade section 3 in the same manner as each chip discharge groove 4. The outer peripheral blades 5 that are twisted in the rearward direction T and whose rotation trajectory around the axis O forms one cylindrical surface centered on the axis O are also formed at intervals in the circumferential direction.

  Further, a groove-like gash 6 is formed at the tip of each chip discharge groove 4 so as to cut out the wall surface facing the end mill rotation direction T toward the inner peripheral side of the end mill body 1. . Then, from the tip of the outer peripheral blade 5, the wall surface of the gash 6 is used as a rake face 8 at the intersecting ridge line portion between the wall surface facing the end mill rotation direction T side of the gash 6 and the tip flank 7 at the tip of the cutting edge 3. Four bottom blades 9 extending toward the inner peripheral side are also formed at intervals in the circumferential direction.

  Here, in the end mill of the present embodiment, these four bottom blades 9 are substantially located on one plane perpendicular to the axis O in the rotation trajectory around the axis O, or from the plane toward the inner peripheral side. The square end mill extends slightly toward the rear end side, and the outer peripheral blade 5 and the bottom blade 9 intersect with each other substantially orthogonally or slightly at an acute angle in the rotation trajectory. Further, as shown in FIG. 2, the gasche 6 in the present embodiment has a wall surface facing the end mill rotation direction T side as a rake face 8 and a wall surface facing the end mill rotation direction T rear side. The bottom portion of the gasche 6 has a substantially V-shaped cross section connected through a concave curved surface.

  Further, of the four gashes 6 formed at the tip of the four chip discharge grooves 4, every other two gashes 6A in the circumferential direction are the remaining two adjacent to the front side in the end mill rotation direction T. The gas wall 6B is formed so as to extend by cutting out the wall surface as the rake face 8 of the bottom blade 9 of the gash 6B and the tip flank 7 of the bottom blade 9 so as to communicate with the gash 6B. On the other hand, the remaining two gashs 6B do not communicate with the gash 6A adjacent to the end mill rotation direction T side, and the bottom blade 9 is interposed between the gash 6A and the bottom blade 9 whose rake surface 8 is the wall surface. The tip flank 7 is formed to remain.

  Therefore, the bottom blades 9 of the two gashes 6A that are not in communication with the gash 6B adjacent to the rear side in the end mill rotation direction T are the bottom blades 9 opposite to each other from the tip of the outer peripheral blade 5 toward the inner peripheral side. The end flank surfaces 7 extend to a position where they intersect with each other, and a long bottom blade 9A extending beyond the axis O at the end of the end mill body 1 is formed. Further, the remaining two bottom blades 9 other than the long bottom blade 9A are short bottom blades 9B whose inner peripheral ends are positioned on the outer peripheral side at a distance from the axis O at the end of the end mill body 1.

  The long bottom blades 9A and the short bottom blades 9B are alternately arranged in the circumferential direction, and the end mill body 1 is formed to be 180 ° rotationally symmetric with respect to the axis O. As shown in FIG. 3, these bottom blades 9 have a distance between the long bottom blade 9A and the short bottom blade 9B adjacent to the front side in the end mill rotation direction T so that the short bottom blade 9B and the end mill rotation direction T It is made larger than the space | interval with the long bottom blade 9A adjacent to the front side.

  Therefore, the outer peripheral blades 5 connected to the outer peripheral ends of these bottom blades 9 are also adjacent to the outer peripheral blades 5 connected to the long bottom blade 9A and the front side in the end mill rotation direction T at least on the distal end side of the cutting blade portion 3. 5 is made larger than the distance between the outer peripheral blade 5 connected to the short bottom blade 9B and the outer peripheral blade 5 adjacent to the front side in the end mill rotation direction T. In addition, the outer peripheral blade 5 may extend toward the rear end side while maintaining such a constant interval, and the leads of the adjacent outer peripheral blades 5 are different, and the interval is increased toward the rear end side. May be changed.

  Furthermore, a plurality (four) of coolant holes 10 having the same number as the bottom blades 9 are formed in the end mill body 1 from the rear end surface of the shank portion 2 toward the front end side. In the present embodiment, these coolant holes 10 have a circular cross section orthogonal to the axis O, and are arranged on one diameter line orthogonal to the axis O in the same cross section, with the axis O sandwiched between the inner peripheral side and the outer peripheral side. The second coolant hole 10B on the outer peripheral side has a larger cross-sectional area than the first coolant hole 10A on the inner peripheral side.

  These coolant holes 10 are formed in a spiral shape so as to be twisted toward the rear side in the end mill rotation direction T around the axis O as it goes toward the rear end in the axis O direction as indicated by broken lines in FIGS. 1 and 2. The lead is made equal to the twisted lead of the chip discharge groove 4, and the second coolant hole 10 </ b> B on the outer peripheral side is a long bottom blade 9 </ b> A in the cutting edge 3 on the tip side of the end mill body 1. Is extended to a portion between the chip discharge groove 4 formed with the outer peripheral blade 5 connected to the chip and the chip discharge groove 4 on the front side in the end mill rotation direction T.

  These coolant holes 10 have a first coolant hole 10A opened at the gash 6A of the long bottom blade 9A at the end of the end mill body 1, and a second coolant hole 10B is the tip escape of the short bottom blade 9B. The surface 7 is opened. In particular, in the present embodiment, the first coolant hole 10A is the axis of the long bottom blade 9A on the wall surface facing the rear side in the end mill rotation direction T of the gasche 6A having a substantially V-shaped cross section as described above. An opening is formed so as to face a portion around O.

  Further, in the present embodiment, the second coolant hole 10B is an intersection ridgeline between the first flank 7A on the end mill rotational direction T side of the tip flank 7 of the short bottom blade 9B and the second flank 7B on the rear side. It is opened to straddle. In the present embodiment, only one pair of the first and second coolant holes 10A, 10B is opened in the tip flank 7 of the pair of long bottom blades 9A and the short bottom blade 9B. The coolant holes other than these are not formed in the end mill body 1.

  In the end mill with the coolant hole thus configured, the distance between the long bottom blade 9A and the short bottom blade 9B adjacent to the front side in the end mill rotation direction T is adjacent to the short bottom blade 9B and the end mill rotation direction T front side. Accordingly, the distance between the outer peripheral blades 5 connected to these bottom blades 9 is also unequal at least on the distal end side of the cutting blade portion 3 as described above. Therefore, the period at which the bottom blade 9 bites the work material when the outer peripheral blade 5 or shoulder is shaved becomes unequal. For this reason, it is possible to prevent periodic vibrations from acting on the end mill body 1 when all the outer peripheral blades 5 and the bottom blades 9 bite into the work material at an equal cycle. Vibration can be prevented from occurring.

  Thus, the distance between the long bottom blade 9A and the short bottom blade 9B adjacent to the front side in the end mill rotation direction T is such that the short bottom blade 9B and the long bottom blade 9A adjacent to the front side in the end mill rotation direction T As shown in FIG. 3, the tip flank 7 of the long bottom blade 9A must be smaller than the tip flank 7 of the short bottom blade 9B. In the end mill with a hole, the coolant hole 10 formed in the end mill main body 1 opens the first coolant hole 10A in the gash 6A of the long bottom blade 9A so as to avoid the tip flank 7 of the long bottom blade 9A. At the same time, the second coolant hole 10B is opened at the tip flank 7 of the short bottom blade 9B.

  For this reason, a large thickness can be secured in the end mill main body 1 on the rear side in the end mill rotation direction T of the long bottom blade 9A, so that it is longer than the short bottom blade 9B and short adjacent to the front side in the end mill rotation direction T. Even in the long bottom blade 9A having a large interval with the bottom blade 9B and a large load during cutting, it is possible to maintain sufficient cutting edge strength and prevent damage such as defects. Moreover, since the pair of first and second coolant holes 10A and 10B are also formed in the end mill body 1 with respect to the pair of long and short bottom blades 9A and 9B, more coolant can be supplied. The bottom blade 9 and the outer peripheral blade 5 can be reliably lubricated and cooled to suppress wear of the flank 7 and the flank of the outer peripheral blade 5. And the chip | tip produced | generated by the outer periphery blade 5 can be discharged | emitted efficiently.

  On the other hand, since the short bottom blade 9B has a large interval with the long bottom blade 9A adjacent to the rear side in the end mill rotation direction T, the tip flank 7 can be enlarged, and the second coolant hole 10B is opened. Also, the cutting edge strength can be maintained. In the present embodiment, the cross-sectional area of the second coolant hole 10B is larger than that of the first coolant hole 10A, and the opening area at the end of the end mill body 1 is also increased. Therefore, the wear resistance of the tip flank 7 of the bottom blade 9 and the flank of the outer peripheral blade 5 can be improved.

  Moreover, in this embodiment, 10 A of 1st coolant holes are opened more to the radial direction inner peripheral side with respect to the axis line O than the 2nd coolant hole 10B, Therefore Of the gashes 6A of the long bottom blade 9A, more The first coolant hole 10A can be opened in the vicinity of the axis O on the inner peripheral side. For this reason, the coolant can be uniformly supplied from the inner peripheral side in the vicinity of the axis O to the outer peripheral side with respect to the long bottom blade 9A extending beyond the axis O. More reliable lubrication and cooling of the bottom blade 9A and more efficient discharge of chips generated more than the short bottom blade 9B can be achieved.

  In the present embodiment, the first coolant hole 10A is entirely opened in the gash 6A of the long bottom blade 9A as described above. For example, a part of the first coolant hole 10A is formed in the tip flank 7 of the short bottom blade 9B. You may be made to open so that it may straddle. Further, in the present embodiment, the second coolant hole 10B is opened so as to straddle the intersecting ridge lines of the first and second flank surfaces 7A and 7B of the tip flank 7 of the short bottom blade 9B. It may be opened only on the flank 7B, or a part thereof may be opened across the wall surface facing the rear side in the end mill rotation direction T of the gash 6A of the long bottom blade 9A.

DESCRIPTION OF SYMBOLS 1 End mill main body 3 Cutting edge part 4 Chip discharge groove 5 Outer peripheral blade 6 (6A, 6B) Gash 7 Tip flank 9 Bottom blade 9A Long bottom blade 9B Short bottom blade 10 Coolant hole 10A 1st coolant hole 10B 2nd coolant Hole O End mill body 1 axis T End mill rotation direction

Claims (3)

  A short bottom having a long bottom blade extending beyond the axis from the outer periphery to the inner periphery of the end mill body at the tip of the end mill body rotated about the axis, and an inner peripheral end at a position away from the axis Blades are alternately formed in the circumferential direction, and the interval between the long bottom blade and the short bottom blade adjacent to the front side in the end mill rotation direction is the long bottom blade adjacent to the short bottom blade and the front side in the end mill rotation direction. And a plurality of coolant holes are formed in the end mill body, and among these coolant holes, the first coolant hole is formed on the front side in the end mill rotation direction of the long bottom blade. An end mill with a coolant hole, wherein the second coolant hole is opened at the tip flank of the short bottom blade.   The end mill with coolant holes according to claim 1, wherein the second coolant hole has an opening area larger than that of the first coolant hole.   3. The end mill with coolant holes according to claim 1, wherein the first coolant hole is opened to a radially inner peripheral side with respect to the axis than the second coolant hole. 4.

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