JP2017080864A - Cutting edge exchange-type reamer and reamer insert - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the rigidity of a front face cutting edge, and to obtain the excellent roughness of a finished surface.SOLUTION: A reamer insert having an insert main body 11 which comprises a rake face 12 oriented to a reamer rotation direction T is attached to a tip external periphery of a reamer main body 1 which rotates around an axial line O while making one corner part C of the rake face 12 protrude to a tip external peripheral side of the reamer main body 1. First, second and third front face cutting edges 13A, 13B and 13C which are sequentially inclined to a rear end side toward an external peripheral side from an internal peripheral side of the reamer main body 1 are formed at the corner part C so that an inclination angle with respect to a plane face P orthogonal to an axial line O when viewed from a direction opposing the rake face 12 gradually becomes large, first and second flanks whose relief angles gradually become large are formed at a side opposite to a reamer rotation direction T of the first front face cutting edge 13A, and a flank having a single relief angle is formed at a side opposite to the reamer rotation direction T of the third front face cutting edge 13C.SELECTED DRAWING: Figure 2

Description

  The present invention provides a reamer in an insert mounting seat formed on the outer periphery of a tip end portion of a reamer main body rotated about an axis, which is used to finish a prepared hole formed in a work material into a machining hole having a predetermined inner diameter. The present invention relates to a blade-replaceable reamer to which an insert is detachably attached and a reamer insert that is removably attached to the insert mounting seat of such a blade-replaceable reamer.

  As such a blade-tip-replaceable reamer, for example, Patent Document 1 is provided with a reamer insert having a cutting blade projecting toward the outer periphery side of the reamer body at the tip of a substantially cylindrical reamer body rotated about an axis. A flank facing the outer periphery of the reamer body of the insert for the reamer has a land having an arc-shaped outer peripheral surface formed so that the radius around the axis gradually decreases from the cutting edge toward the rear side in the reamer rotation direction. The one provided with is proposed. In such a blade-replaceable reamer, when the reamer body is extracted from the machining hole after finishing, the arc-shaped outer peripheral surface of the flank surface comes into surface contact with the inner peripheral surface of the machining hole, so that the machining hole is damaged. There is no.

Japanese Patent No. 38765577

  However, if such an arcuate surface is formed on the flank of the front cutting edge that bites into the pilot hole formed in the work material, the thickness of the insert on the side opposite to the reamer rotation direction of the front cutting edge is reduced. When the cutting edge strength is impaired, especially when the machining allowance is increased in order to perform high-efficiency machining of work materials made of aluminum alloy, or when high feed is performed by high feed, There is a risk of chipping or chipping on the front cutting edge. In addition, when the machining allowance is increased in this way, if the front cutting edge bites into the opening of the pilot hole at once in a wide range in the radial direction with respect to the axis line, an impact load acts, and the front cutting edge is also missing. As a result, the quality of the processed hole that is finished by inviting chipping is impaired.

  The present invention has been made under such a background, and even when the machining allowance or feed is increased in high-efficiency machining, the strength of the front cutting edge can be ensured and no chipping or chipping occurs. An object of the present invention is to provide a blade-replaceable reamer and an insert for a reamer capable of obtaining an excellent finished surface roughness.

  In order to solve the above-mentioned problems and achieve such an object, the blade-replaceable reamer according to the present invention has a reamer insert attached to and detached from an insert mounting seat formed on the outer periphery of the distal end portion of the reamer main body rotated about the axis. A blade-replaceable reamer that is detachably mounted, wherein the insert for reamer has an insert body having a rake face directed in a reamer rotation direction, and one corner portion of the rake face is provided at a tip of the reamer body. The first front edge, the second front edge and the third front edge are formed in order from the inner peripheral side of the reamer body toward the outer peripheral side. The first, second, and third front cutting edges are inclined toward the rear end side toward the outer peripheral side of the reamer body, and when viewed from the direction facing the rake face. The first and second flank surfaces in which the inclination angle with respect to the plane orthogonal to the axis increases stepwise, and the clearance angle increases stepwise on the side opposite to the reamer rotation direction of the first front cutting edge. And a relief surface having a single relief angle is formed on the side opposite to the reamer rotation direction of the third front cutting edge.

  The reamer insert according to the present invention is a reamer insert that is detachably attached to an insert mounting seat formed on an outer periphery of a tip portion of a reamer main body of a blade-replaceable reamer that is rotated around an axis. An insert body having a rake face directed toward the rim, and one corner portion of the rake face projected to the outer peripheral side of the tip of the reamer body intersects at an obtuse angle when viewed from the direction facing the rake face The first, second, and third front cutting edges are formed in order, and the flank of the first front cutting edge that is directed toward the distal end side of the reamer body is the first front cutting edge. The first and second flank surfaces have a flank angle that increases stepwise as they move away from the flank, and the flank surface of the third front cutting edge directed toward the outer periphery of the reamer body has a single flank angle. And characterized in that it.

  When such a reamer insert is viewed from the direction in which the first, second, and third front cutting edges intersecting the obtuse angle face the rake face as described above, the inclination angle with respect to the plane perpendicular to the axis is as follows. In the blade-replaceable reamer of the above configuration, which is mounted so as to increase in stages, when these front cutting edges bite into the opening of the pilot hole formed in the work material, first the inner periphery side of the reamer body The first front cutting edge with the smallest inclination angle bites, then the second front cutting edge with the second smallest inclination angle bites, and finally the largest inclination angle, that is, parallel to the axis of the reamer body The third front cutting edge close to is bitten. For this reason, it is possible to disperse the impact when the front cutting edge bites and prevent chipping and chipping.

  Of the first, second, and third front cutting edges, the flank of the first front cutting edge moves away from the first front cutting edge, that is, opposite to the reamer rotation direction. Accordingly, first and second flank surfaces whose flank angles increase stepwise are provided. Therefore, for example, in the position of the cutting edge of this arcuate surface compared to the one having an arcuate surface whose radius gradually decreases as the clearance surface is separated from the cutting edge, such as the blade-replaceable reamer described in Patent Document 1. If the clearance angle, that is, the angle formed by the tangent at the position of the cutting edge of the arcuate surface with respect to the straight line perpendicular to the rake face in the cross section perpendicular to the cutting edge is equal to the clearance angle of the first flank face, The first flank can be projected outward from the arcuate surface, and a large thickness of the insert body can be ensured on the side opposite to the reamer rotation direction of the first front cutting edge.

  For this reason, it is possible to improve the cutting edge strength of the first front cutting edge, and when the machining allowance is increased in high-efficiency machining or when high feed machining is performed, the cutting operation with the highest load state is performed. It is possible to prevent chipping or chipping of the front cutting edge of 1. In addition, on the opposite side to the first front cutting edge with the first flank in between, that is, on the side opposite to the reamer rotation direction of the first flank connected to the first front cutting edge, Since the second flank is formed with a larger flank than the flank, even when performing high-feed machining as described above, the flank of the first front cutting edge becomes a pilot hole in the work material. Interference can be avoided to produce a so-called second hit. On the other hand, the second and third front cutting edges located on the outer peripheral side of the reamer main body with respect to the first front cutting edge have a larger inclination angle than the first front cutting edge, and one rotation of the reamer main body. Since the substantial cut amount per hit can be reduced, the load in the thrust direction can be reduced.

  Further, the third front surface, which is located on the outermost periphery of the reamer main body and has the largest inclination angle with respect to the plane orthogonal to the axis as described above, is closer to the reamer main body axis than the first and second front cutting edges In the cutting edge, even if high-feed machining is performed, there is little possibility that the flank will interfere with the pilot hole of the work material. Therefore, the flank of the third front cutting edge is used as the first front cutting edge. By having a relatively small single clearance angle as well as the flank, it is possible to prevent the third front cutting edge from being chipped or chipped. Then, the pilot hole whose diameter has been expanded by the first and second front cutting edges is cut so as to be finally swept away by the third front cutting edge close to parallel to the axis of the reamer body. By being finished, the inner peripheral surface of the finished processed hole can be formed with high quality and excellent finished surface roughness.

  Here, the inclination angle of the first, second, and third front cutting edges with respect to the plane orthogonal to the axis when viewed from the direction facing the rake face is the inclination angle of the first front cutting edge. Is preferably in the range of 5 ° to 30 °, the inclination angle of the second front cutting edge is preferably in the range of 30 ° to 70 °, and the inclination angle of the third front cutting edge is Is preferably 85 ° or more as the inclination angle of the straight line connecting both ends of the third front cutting edge.

  If the inclination angle of the first front cutting edge is smaller than 5 °, the entire first front cutting edge may bite into the opening of the pilot hole at once, and the impact load may not be sufficiently reduced. . Further, when the inclination angle is larger than 30 °, the axial length of the first front cutting edge or the axis lines of the second and third front cutting edges whose inclination angle is larger than that of the first front cutting edge. The length in the direction also becomes longer, and the insert body itself becomes longer in the axial direction than necessary.

  Further, with respect to the second front cutting edge, if the inclination angle is smaller than 30 °, the difference from the inclination angle of the first front cutting edge becomes small, and the impact load can be sufficiently reduced. On the contrary, if the inclination angle is larger than 70 °, the insert body may be lengthened. Of course, the inclination angles of the first and second front cutting edges are never 30 °. Moreover, about the 3rd front cutting edge, when the said inclination | tilt angle is smaller than 85 degrees, a pilot hole is finally wiped out as mentioned above with this 3rd front cutting edge, and an improvement in finishing surface roughness is carried out. There is a risk that it will be difficult to achieve this. The inclination angle of the third front cutting edge never exceeds 90 °.

  On the other hand, it is desirable that the clearance angle of the first flank face connected to the side opposite to the reamer rotation direction of the first front cutting edge is 7 ° or less, which is opposite to the reamer rotation direction of the first flank face. It is desirable that the clearance angle of the second flank face connected to the side is 10 ° or more. When the clearance angle of the first flank of the first front cutting edge exceeds 7 °, it is possible to sufficiently secure the thickness of the insert body on the side opposite to the reamer rotation direction T of the first front cutting edge. If the flank angle of the second flank is less than 10 °, the flank contact as described above may occur.

  In addition, the flank of the second front cutting edge may be provided with the first and second flank like the flank of the first front cutting edge, or the third front cutting flank Similarly, it may have a single clearance angle. However, when the first and second flank surfaces in which the clearance angle increases stepwise are formed on the opposite side of the reamer rotation direction of the second front cutting edge as in the former case, the first front surface For the same reason as the clearance angles of the first and second flank faces of the cutting edge, the clearance angle of the first flank face of the second front cutting edge is desirably 7 ° or less, The clearance angle of the second flank of the blade is preferably 10 ° or more.

  Furthermore, it is desirable that a side cutting edge is provided from the outer peripheral end of the third front cutting edge toward the rear end side of the reamer body, and the clearance angle is also provided on the side opposite to the reamer rotation direction of the side cutting edge. It is desirable to form first and second flank surfaces that increase in a stepwise manner. By forming the side cutting edge having such first and second flank surfaces, the finished surface roughness of the processed hole formed by the third front cutting edge is further improved, and the side cutting edge of the side cutting edge is improved. The cutting edge strength can be maintained while ensuring the necessary clearance.

  The third front cutting edge may extend to the rear end side of the reamer body in a straight line along the straight line connecting both ends as it goes toward the outer peripheral side of the reamer body, but it faces the rake face. When viewed from the direction of the reamer, it may be formed so as to form a convex curve such as an arc having a radius of 0.2 mm or more and to extend toward the rear end side toward the outer peripheral side of the reamer body. The finished surface roughness of the processed hole can be improved by the convex front third cutting edge having a large radius.

  Even when the third front cutting edge has a convex curve shape or extends in a straight line, the insert mounting seat and the outer periphery of the distal end of the reamer body By providing a guide pad on the opposite side, the guide pad is pressed against the inner peripheral surface of the machining hole by the back component force of the cutting force acting on the third front cutting edge, and the burnishing effect is further improved. Finished surface roughness can be obtained.

  As described above, according to the present invention, when finishing a pilot hole formed in a work material into a machining hole with a predetermined inner diameter, even when the machining allowance and feed are increased by high-efficiency machining, It is possible to ensure the strength of the cutting edge to prevent chipping and chipping, and to give excellent quality and finished surface roughness to the finished hole thus finished.

It is a top view which shows one Embodiment of the blade-tip-exchange-type reamer of this invention. It is an enlarged plan view of the front-end | tip part of embodiment shown in FIG. It is the enlarged front view which looked at embodiment shown in FIG. 1 from the axial direction front end side. It is the top view seen from the direction which opposes the rake face which shows one Embodiment of the insert for reamers of this invention attached to the blade-tip-exchange-type reamer of embodiment shown in FIG. It is the enlarged front view which looked at embodiment shown in FIG. 4 from the front end side. It is the expanded side view seen from the arrow X direction (direction along the 1st front cutting edge) in FIG. It is an enlarged plan view which shows one corner part of the rake face in embodiment shown in FIG. It is the side view seen from the arrow X direction (direction along the 2nd front cutting edge) in FIG. It is the side view seen from the arrow Y direction (direction along the 3rd front cutting edge) in FIG.

  FIGS. 1 to 3 show an embodiment of the blade-replaceable reamer of the present invention, and FIGS. 4 to 9 show the insert for the reamer of the present invention attached to the blade-replaceable reamer of this embodiment. 1 illustrates one embodiment. The blade-replaceable reamer of the present embodiment has a reamer body 1 formed in a substantially cylindrical shape with an axis O as the center, and a rear end portion (right side portion in FIG. 1) of the reamer body 1 is cylindrical. The end portion (left side portion in FIG. 1) is a cutting blade portion 3, and the portion between the shank portion 2 and the cutting blade portion 3 is slightly smaller than the shank portion 2. A small-diameter columnar neck 4 is formed.

  In addition, the reamer main body 1 of the present embodiment includes a portion from the shank portion 2 to the center portion of the neck portion 4 formed of a hard material such as cemented carbide and a portion including the cutting edge portion 3 on the tip side from this. Is formed of steel material or the like having a hardness lower than that of the shank portion 2, and these are joined and integrated coaxially by brazing or the like. Such a blade-tip-replaceable reamer is formed on a work material by feeding the shank portion 2 to the front end side in the axis O direction while being gripped by the spindle of the machine tool and rotating in the reamer rotation direction T around the axis O. The cutting blade portion 3 is inserted into the prepared hole, and the prepared hole is finished into a processed hole having a predetermined inner diameter.

  On the outer periphery of the cutting edge 3 that is the tip of the reamer body 1, a chip discharge groove 5 that opens at the tip of the cutting edge 3 and extends to the rear end is parallel to the axis O in the present embodiment. An insert mounting seat 6 is formed on the surface of the chip discharge groove 5 facing the reamer rotation direction T. The insert mounting seat 6 includes a bottom surface facing the reamer rotation direction T, a wall surface facing the outer peripheral side of the reamer body 1, and a wall surface facing the distal end side, and the tip mounting surface 6 and the outer peripheral surface of the cutting blade portion 3 and the chip discharge groove 5. It is formed in a concave groove shape that opens and extends in the direction of the axis O, and the insert for reamer of this embodiment is detachably attached to this insert mounting seat 6.

  The insert for reamer of this embodiment has the insert main body 11 formed in the shape of a quadrangular prism as shown in FIG.4 and FIG.5. That is, the insert main body 11 includes a rectangular first to fourth side surfaces 11A to 11D extending in the longitudinal direction (left and right direction in FIG. 4), and a substantially trapezoidal tip end surface 11E that faces the longitudinal direction. And a rear end face 11F.

  Of these, one corner portion C of the first side surface 11A where the first side surface 11A intersects with the second side surface 11B and the front end surface 11E adjacent to the first side surface 11A, particularly the corner portion C of the first side surface 11A. The first, second, and third front cutting edges 13A, 13B, and 13C having the rake face 12 as the periphery intersect with each other at an obtuse angle when viewed from the direction facing the rake face 12, and the first face 11E It forms in order toward the 2nd side 11B. Further, at the intersection ridge line portion between the first side surface 11A and the second side surface 11B, the end portion of the third front cutting edge 13C opposite to the second front cutting edge (attached to the reamer main body 1). A side cutting edge 13D is formed from the outer peripheral end of the third front cutting edge 13C in the state toward the rear end face 11F side. In the present embodiment, the first, second, and third front cutting edges 13A, 13B, and 13C and the side cutting edge 13D are all formed in a straight line.

  In the present embodiment, the portion on the second side surface 11B side of the tip surface 11E is a bent surface slightly bent at an obtuse angle with respect to the portion on the third side surface 11C side opposite thereto. The portion on the front end surface 11E side of the second side surface 11B is also a bent surface that is bent slightly at an obtuse angle with respect to the portion on the rear end surface 11F side opposite thereto. Further, a chamfered surface that intersects both the bent surfaces at an obtuse angle is formed on the first side surface 11A side of the intersecting ridge line portion where the bent surfaces of the tip surface 11E and the second side surface 11B intersect.

  The first, second, and third front cutting edges 13A, 13B, and 13C that intersect at an obtuse angle with each other at the intersecting ridge line portion between the bent surface and the chamfered surface and the first side surface 11A as described above. Is formed. Therefore, in this embodiment, these bent surfaces and chamfered surfaces are the flank surfaces 14A of the first, second, and third front cutting edges 13A, 13B, and 13C in this order from the front end surface 11E toward the second side surface 11B. , 14B, 14C.

  Further, in the insert main body 11, a front end surface 11E including the flank 14A of the first front cutting edge 13A, a second side surface 11B including the flank 14C of the third front cutting edge 13C, and a second front surface. The chamfered surface serving as the flank 14B of the cutting edge 13B and the second side surface 11B serving as the flank 14D of the side cutting edge 13D intersect the first side surface 11A including the rake face 12 at an acute angle. Therefore, the reamer insert of this embodiment is a positive type cutting insert. Further, the first side surface 11A, the third side surface 11C opposite to the second side surface 11B, and the rear end surface 11F are orthogonal to each other or extend in a direction orthogonal to each other. The fourth side surface 11D and the third side surface 11C opposite to each other extend in a direction intersecting at an acute angle.

  Here, among these flank faces 14A, 14B, 14C, 14D, in this embodiment, the flank faces 14A, 14B of the first and second front cutting edges 13A, 13B and the flank face 14D of the side face cutting edge 13D are: First and second flank faces 14a and 14b are provided which have escaping angles α1 and α2 that increase stepwise as they are separated from the first and second front cutting edges 13A and 13B and the side cutting edges 13D, respectively. Yes. In each of the first and second front cutting edges 13A and 13B and the flank faces 14A, 14B and 14D of the side cutting edge 13D, the clearance angle α1 of the first flank face 14a is 7 ° or less, and this embodiment Is 5 °, and the clearance angle α2 of the second flank 14b is 10 ° or more, and is 12 ° in the present embodiment.

  On the other hand, the flank 14C of the third front cutting edge 13C is a one-step flank having a single clearance angle β. That is, the flank 14C of the third front cutting edge 13C is formed in a single plane that intersects the rake face 12 at an acute angle, and the flank angle β is, for example, the first and second front cutting edges. It is set equal to the clearance angle α1 of the first clearance surface 14a at the clearance surfaces 14A, 14B of the blades 13A, 13B and is equal to or less than 7 °, and is 5 ° in this embodiment. The flank 14C having a single clearance angle β of the third front cutting edge 13C is, for example, the first front cutting edge of the first flank 14a in the flank 14A of the first front cutting edge 13A. It suffices if it is formed to a range exceeding the flank width from 13A, and a flank or chamfered surface with a larger flank angle may be formed on the side opposite to the reamer rotation direction T.

  Further, the bent surface and the chamfered surface as described above are formed, and the first, second, and third front cutting edges 13A, 13B, and 13C are formed at the intersecting ridge line portion with the first side surface 11A. As shown in FIG. 7, the intersecting ridge line portion between the first side surface 11A and the portion on the third side surface 11C side that is perpendicular to the first side surface 11A including the rake face 12 and is opposite to the bent surface of the tip end surface 11E. The inclination angles θ1, θ2, and θ3 formed when the first, second, and third front cutting edges 13A, 13B, and 13C are viewed from the direction perpendicular to the rake face 12 with respect to the plane P including L are In this order, it becomes gradually larger.

  Here, the inclination angle θ1 formed by the first front cutting edge 13A is in the range of 5 ° to 30 ° and is 15 ° in the present embodiment, and the inclination angle θ2 of the second front cutting edge 13B is 30 °. Within the range of ˜70 ° and 55 ° in the present embodiment, the inclination angle θ3 of the third front cutting edge 13C is 85 ° or more, and in this embodiment is 87 °. Of course, the inclination angles θ1 and θ2 of the first and second front cutting edges 13A and 13B do not both become 30 °. In the present embodiment, the side cutting edge 13D is parallel to the axis O. Furthermore, the lengths of the first, second, and third front cutting edges 13A, 13B, and 13C in the intersecting ridge line portion L direction become shorter in this order.

  The insert body 11 in this embodiment is disposed in a base 15 made of cemented carbide and a recess 15A formed in a corner including the corner portion C on the first side surface 11A of the base 15. For example, it is formed by a cutting edge tip 16 made of a polycrystalline diamond sintered body containing diamond particles harder than the base metal 15. Here, the diamond particles contained in the polycrystalline diamond sintered body are desirably fine particles having an average particle diameter of 1 μm or less.

  As shown in FIGS. 5 and 6, such a cutting edge tip 16 is a layered sintered body obtained by laminating the polycrystalline diamond sintered body layer 16 </ b> A and the cemented carbide layer 16 </ b> B and sintering them integrally. The cemented carbide layer 16B is bonded to the recess 15A of the base metal 15 by brazing or the like so that the polycrystalline diamond sintered body layer 16A faces the first side surface 11A. Established. Accordingly, the first, second, and third front cutting edges 13A, 13B, and 13C and the side cutting edge 13D are formed in the polycrystalline diamond sintered body layer 16A of the cutting edge chip 16.

  In such an insert for reamer, the first side surface 11A including the rake face 12 of the insert body 11 is directed to the insert mounting seat 6 of the reamer body 1 in the reamer rotation direction T, and the tip surface 11E is directed to the reamer body 1. The second side surface 11B is directed to the outer peripheral side of the reamer body 1 on the front end side, the fourth and third side surfaces 11D and 11C and the rear end surface 11F are the bottom surface of the insert mounting seat 6, and the outer peripheral side of the reamer body 1 is disposed. It is seated in contact with the wall surface facing and the wall surface facing the tip side.

  In the reamer insert thus seated, the first side face 11A is pressed by the clamp piece 22 by further screwing the clamp screw 21 into the reamer main body 1, and the one corner portion C of the rake face 12 is pushed into the reamer. The main body 1 is detachably attached to the insert mounting seat 6 so as to protrude toward the outer peripheral side of the tip. Further, an adjustment screw 23 is screwed into the cutting blade portion 3 of the reamer main body 1, and by adjusting the screwing amount of the adjustment screw 23, the adjustment screw 23 is brought into contact with the third side surface 11 </ b> C of the insert main body 11 obliquely. An adjustment pin (not shown) is pushed in so that the radial position of the insert body 11 with respect to the axis O can be adjusted.

  With the position adjusted and attached to the insert mounting seat 6, the reamer insert has a first side surface 11 A including the rake face 12 of the insert body 11 on a plane including the axis O of the reamer body 1. Or in a plane parallel to the axis O, and in the cutting edge replaceable reamer of the present embodiment, it is arranged on a plane including the axis O. Furthermore, the intersecting ridge line portion L between the portion on the third side surface 11C side opposite to the bent surface of the tip surface 11E of the insert body 11 and the first side surface 11A is in a direction perpendicular to the axis O of the reamer body 1. Therefore, the plane P including the intersecting ridge line L and perpendicular to the rake face 12 is also arranged to be orthogonal to the axis O as shown in FIG. Further, the side cutting edge 13D is disposed in parallel with the axis O.

  In the reamer body 1, a coolant hole 24 extends from the rear end surface of the shank portion 2 along the axis O toward the front end side to the vicinity of the rear end of the cutting blade portion 3. This coolant hole 24 branches to the outer peripheral side perpendicular to the axis O at the neck 4, opens into a long groove 25 formed in the outer peripheral surface of the neck 4 in the direction of the axis O, and toward the distal end side of the reamer body 1. Accordingly, the long groove 25 extending to the outer peripheral surface of the insert mounting seat 6 on the T reamer rotation direction T side is also opened. Coolant such as cutting fluid is supplied.

  Furthermore, a first guide pad 26 </ b> A is provided on the outer peripheral surface of the cutting edge portion 3 on the side opposite to the insert mounting seat 6 with the axis O therebetween. In the present embodiment, the position between the insert mounting seat 6 adjacent to the opposite side of the reamer rotation direction T and the position between the insert mounting seat 6 and the first guide pad 26A in the reamer rotation direction T. Also, two second guide pads 26B are provided respectively.

  The first and second guide pads 26A and 26B are formed in a long plate shape from a hard material such as cemented carbide, and are formed in a groove extending in the direction of the axis O formed on the outer peripheral surface of the cutting edge portion 3. It is joined by brazing or the like, and its outer peripheral surface is slightly smaller than the diameter of the circle formed by the outer peripheral end of the third front cutting edge 13C of the insert main body 11 attached to the insert mounting seat 6 around the axis O. It is arranged so as to be located on a cylindrical surface centering on an axis O having a small diameter. Further, the tips of the first and second guide pads 26A and 26B are slightly retracted toward the rear end side of the reamer body 1 with respect to the plane P shown in FIG.

  In the blade-replaceable reamer and the reamer insert configured as described above, in the present embodiment, the intersecting ridge line portion L of the insert body 11 is positioned on the plane P orthogonal to the axis O of the reamer body 1. The insert for use inclines so that the first, second, and third front cutting edges 13A, 13B, and 13C intersecting each other at an obtuse angle at the corner portion C are directed toward the rear end side toward the outer peripheral side of the reamer body 1, The reamer body 1 is attached so that the inclination angles θ1, θ2, and θ3 with respect to the plane P when viewed from the direction facing the rake face 12 are increased stepwise.

  Therefore, when the first, second, and third front cutting edges 13A, 13B, and 13C bite into the opening of the prepared hole formed in the work material, first, the inner periphery of the reamer body 1 The first front cutting edge 13A with the smallest inclination angle θ1 on the side bites, then the second front cutting edge 13B with the second smallest inclination angle θ2 bites, and finally the inclination angle θ3 is the largest The third front cutting edge 13C closer to the axis O of the reamer body 1 than the first and second front cutting edges 13A, 13B bites. Therefore, it becomes possible to disperse the impact when the first, second, and third front cutting edges 13A, 13B, and 13C bite the work material, and the first, second, and third front cutting edges. It is possible to prevent defects and chipping from occurring in 13A, 13B, and 13C.

  Further, among these, the flank 14A of the first front cutting edge 13A that first bites on the work material is separated from the first front cutting edge 13A, that is, as it goes to the opposite side to the reamer rotation direction T. The first and second clearance surfaces 14a and 14b have clearance angles α1 and α2 that increase stepwise. For this reason, the flank angle at the position of the cutting edge of the arcuate surface is smaller than the flank angle α1 of the first flank surface 14a, compared to the flank having an arcuate surface as in the blade-replaceable reamer described in Patent Document 1. If so, in the cross section perpendicular to the first front cutting edge 13A, the first flank 14a can be projected outward from the arcuate surface as the distance from the first front cutting edge 13A increases. .

  Therefore, the wall thickness of the insert main body 11 can be ensured to be larger on the side opposite to the reamer rotation direction T of the first front cutting edge 13A, whereby the first front cutting edge 13A has a high cutting edge. Can give strength. For this reason, especially when the machining allowance and feed are increased in high-efficiency machining of an aluminum alloy, the first front cutting edge 13A that is in the highest load state by increasing the cutting range and the cutting amount per reamer main body rotation. With respect to, loss and chipping can be reliably prevented.

  Further, the second flank 14b of the flank 14A of the first front cutting edge 13A connected to the opposite side of the first flank 14a in the direction opposite to the reamer rotation direction T is a clearance angle of the first flank 14a. The clearance angle α2 is larger than α1. For this reason, even when performing the above-described high-feed machining, it is possible to prevent the flank 14A of the first front cutting edge 13A from interfering with the pilot hole of the work material and causing the second hit. .

  Furthermore, the second and third front cutting edges 13B and 13C located on the outer peripheral side of the reamer main body 1 with respect to the first front cutting edge 13A are more inclined than the inclination angle θ1 of the first front cutting edge 13A. Since θ2 and θ3 are large, the actual cutting amount per rotation of the reamer body 1 is small. Therefore, it is possible to reduce the load in the thrust direction and to prevent the second and third front cutting edges 13B and 13C from being damaged or chipped.

  Furthermore, among these, the third front cutting edge 13C has the largest inclination angle θ3 and is nearly parallel to the axis O, and the flank 14C remains the flank of the first front cutting edge 13A even when high feed processing is performed. There is little possibility of interference with the pilot hole as in 14A. For this reason, the flank 14C of the third front cutting edge 13C has a small single clearance angle similar to the first flank 14a in the flank 14A of the first front cutting edge 13A as in this embodiment. By setting to β, it is possible to prevent the third front cutting edge 13C from being chipped or chipped.

  In addition, the pilot hole cut so as to increase in diameter stepwise by the first and second front cutting edges 13A and 13B having the small inclination angles θ1 and θ2 has the largest inclination angle θ3 and is on the axis O. By being cut so as to be scraped off by the third front cutting edge 13C which is close to parallel, it is finally finished smoothly and a processed hole is formed. For this reason, the processed hole finished in this way can be made high-quality with excellent finished surface roughness.

  In addition, in the present embodiment, the side cutting edge 13D is provided from the outer peripheral end of the third front cutting edge 13C toward the rear end side of the reamer body 1, and is finished by the third front cutting edge 13C. The machined hole can be finished to a higher quality. Further, on the side opposite to the reamer rotation direction T of the side cutting edge 13D, a relief surface 14D composed of first and second relief surfaces 14a, 14b in which the relief angles α1, α2 are increased stepwise is formed. Therefore, it is possible to prevent the second hit by securing the necessary escape while ensuring the cutting edge strength.

  When finishing is performed by the third front cutting edge 13C having a large inclination angle θ3 and being parallel to the axis O or the side cutting edge 13D parallel to the axis O in this way, the insert body 11 is reamed during cutting. Of the cutting force acting on the main body 1, the back force acting toward the inner peripheral side perpendicular to the axis O increases, but in this embodiment, the insert mounting seat 6 to which the insert main body 11 is attached is the axis. A first guide pad 26A is provided on the opposite side with O in between, and the back component force can be received by the first guide pad 26A. In addition, by receiving the back component force in this way, a burnishing effect can be obtained in which the first guide pad 26A is smoothed by rubbing the inner peripheral surface of the finished machining hole. The finished surface roughness of the hole can be further improved.

  Here, if the inclination angle θ1 of the first front cutting edge 13A is too small, the entire first front cutting edge 13A bites into the opening of the pilot hole at once and sufficiently reduces the shocking load. On the other hand, if the inclination angle θ1 is too large, the length of the first front cutting edge θ1 in the direction of the axis O increases, and accordingly, the second and third front cutting edges 13B and 13C. As a result, the length of the insert body 11 itself becomes longer than necessary. For this reason, the inclination angle θ1 with respect to the plane P of the first front cutting edge 13A when viewed from the direction facing the rake face 12 is in the range of 5 ° to 30 ° as in the present embodiment. desirable.

  Also, with respect to the second front cutting edge 13B, if the inclination angle θ2 is too small, the angle difference with the inclination angle θ1 of the first front cutting edge 13A becomes small, and an impact load at the time of biting is applied. On the other hand, there is a possibility that it cannot be sufficiently relaxed. On the other hand, if the inclination angle is too large, the insert body 11 may be lengthened. For this reason, it is desirable that the inclination angle θ2 of the second front cutting edge 13B is also in the range of 30 ° to 70 ° as in this embodiment.

  Furthermore, if the inclination angle θ3 of the third front cutting edge 13C is too small, the rear end of the third front cutting edge 13C opposite to the bent surface on the second side surface 11B of the insert body 11 is reversed. The intersecting ridge line portion between the end surface 11F side portion and the first side surface 11A forms a corner portion and intersects the third front cutting edge 13C, and the pilot hole is finally wiped smoothly as described above. It may be difficult to finish. For this reason, it is desirable that the inclination angle θ3 of the third front cutting edge 13C is 85 ° or more as in this embodiment.

  Here, in the present embodiment, the third front cutting edge 13C is formed in a straight line like the first and second front cutting edges 13A and 13B, but the third front cutting edge 13C is When viewed from the direction facing the rake face 12, a convex curve such as a large arc having a radius of 0.2 mm or more may be formed. The convex front curved third cutting edge 13C having such a large radius is arranged so as to extend toward the rear end side toward the outer peripheral side of the reamer body 1 at an inclination angle θ3 close to parallel to the axis O as described above. Also, the inner peripheral surface of the processed hole can be smoothly scraped and finished.

  The inclination angle θ3 in this case may be an angle formed by a straight line connecting both ends of the convex curved third front cutting edge 13C with respect to the plane P. In addition, the convex curved third front cutting edge 13C has an outer peripheral end, a portion on the rear end surface 11F side opposite to the bent surface in the second side surface 11B of the insert body 11, and the first end. It is desirable to be in contact with the side cutting edge 13D formed at the intersection ridge line with the side surface 11A.

  On the other hand, if the clearance angle α1 of the first flank 14a directly connected to the opposite side of the reamer rotation direction T of the first front cutting edge 13A among the flank 14A of the first front cutting edge 13A is too large, There is a possibility that the cutting edge strength of the first front cutting edge 13A cannot be sufficiently secured, and the chipping and chipping cannot be surely prevented. In addition, in the flank 14A of the first front cutting edge 13A, if the flank angle α2 of the second flank 14b continuous to the opposite side of the reamer rotation direction T of the first flank 14a is too small, The second flank 14b may interfere with the pilot hole and cause a second hit. Therefore, as in this embodiment, the clearance angle α1 of the first clearance surface 14a of the clearance surface 14A of the first front cutting edge 13A is desirably 7 ° or less, and the clearance angle of the second clearance surface Is preferably 10 ° or more.

  In the present embodiment, the flank 14B of the second front cutting edge 13B and the flank 14D of the side cutting edge 13D are the same as the flank 14A of the first front cutting edge 13A. The first and second flank surfaces 14a and 14b that gradually increase in flank angles α1 and α2 as they move away from 13B and the side cutting edge 13D and move away from the reamer rotation direction T are provided. And, like the flank 14A of the first front cutting edge 13A, the flank angle α1 of the second front cutting edge 13B and the first flank 14a of the side cutting edge 13D is set to 7 ° or less, and the second Since the clearance angle α2 of the second flank 14b of the front cutting edge 13B is set to 10 ° or more, the second hit can be prevented while ensuring the cutting edge strength.

  However, in this embodiment, the flank 14B of the second front cutting edge 13B is also provided with the first and second flank 14a and 14b in which the flank angles α1 and α2 increase stepwise. For example, when the inclination angle θ2 of the second front cutting edge 13B is relatively large and the flank face 14B is less likely to cause a second hit, the second flank cutting face 13C is similar to the flank face 14C of the third front cutting edge 13C. The flank 14B of the second front cutting edge 13B may also have a single flank α1 equal to or less than 7 ° equal to the first flank 14a.

1 Reamer body 3 Cutting edge (tip of reamer body 1)
5 Chip discharge groove 6 Insert mounting seat 11 Insert body 12 Rake face 13A First front cutting edge 13B Second front cutting edge 13C Third front cutting edge 13D Side cutting edge 14A Flank of first front cutting edge 13A 14B Flank face of second front cutting edge 13B 14C Flank face of third front cutting edge 13C 14D Flank face of side cutting edge 13D 14a First flank face 14b Second flank face 16 Cutting edge tip 16A Cutting edge tip 16 diamond sintered body 26A first guide pad O axis of reamer body 1 T reamer rotation direction C one corner of rake face 12 plane perpendicular to axis O 1 tilt of first front cutting edge 13A Angle θ2 Inclination angle of second front cutting edge 13B θ3 Inclination angle of third front cutting edge 13C α1 Relief angle of first flank 14a α2 Relief angle of second flank 14b β Third Clearance angle of the flank 14C of Mensetsuha 13C

Claims (8)

A blade-replaceable reamer in which an insert for a reamer is detachably attached to an insert mounting seat formed on the outer periphery of the distal end portion of the reamer main body rotated about an axis,
The insert for the reamer has an insert body having a rake face directed in the reamer rotation direction, and is attached to the insert mounting seat with one corner portion of the rake face protruding toward the outer peripheral side of the tip end of the reamer body. ,
The corner portion is formed with first, second, and third front cutting edges in order from the inner peripheral side to the outer peripheral side of the reamer main body, and these first, second, and third front cutting edges are formed. The blade is inclined toward the rear end side toward the outer peripheral side of the reamer body, and the inclination angle with respect to the plane orthogonal to the axis when viewed from the direction facing the rake face is increased stepwise.
Among these, the first and second flank surfaces are formed on the side opposite to the reamer rotation direction of the first front cutting edge so that the clearance angle increases stepwise, and the reamer of the third front cutting edge is formed. A blade-replaceable reamer, characterized in that a flank having a single clearance angle is formed on the side opposite to the rotational direction.   The inclination angle of the first, second, and third front cutting edges with respect to the plane perpendicular to the axis when viewed from the direction facing the rake face is 5 °. The inclination angle of the second front cutting edge is in the range of 30 ° to 70 °, and the inclination angle of the third front cutting edge is the third front cutting edge. The blade tip replaceable reamer according to claim 1, wherein the inclination angle of a straight line connecting both ends of the blade is 85 ° or more.   The flank angle of the first flank facing the side opposite to the reamer rotation direction of the first front cutting edge is 7 ° or less, and the flank rotation direction of the first flank is continuous to the side opposite to the reamer rotation direction. The blade edge replaceable reamer according to claim 1 or 2, wherein the clearance angle of the second flank is 10 ° or more.   First and second flank surfaces whose escaping angles increase stepwise are also formed on the side opposite to the reamer rotation direction of the second front cutting edge. 4. The clearance angle of the flank face is 7 [deg.] Or less, and the clearance angle of the second flank face of the second front cutting edge is 10 [deg.] Or more. The cutting edge replaceable reamer according to one item.   A side cutting edge is provided from the outer peripheral end of the third front cutting edge toward the rear end side of the reamer body, and the clearance angle is stepwise on the side opposite to the reaming direction of the side cutting edge. The blade tip replaceable reamer according to any one of claims 1 to 4, wherein first and second flank surfaces are formed.   The third front cutting edge has a convex curve having a radius of 0.2 mm or more when viewed from a direction facing the rake face. The cutting edge replaceable reamer according to one item.   The guide pad is provided in the outer periphery of the front-end | tip part of the said reamer body on the opposite side to the said insert mounting seat with the said axis line in between, The Claim 1 characterized by the above-mentioned. The blade tip replaceable reamer described in 1. An insert for a reamer that is detachably attached to an insert mounting seat formed on the outer periphery of the tip of the reamer main body of a reamer body that is rotated around an axis,
An insert main body having a rake face directed in the reamer rotation direction, and one corner portion of the rake face protruding to the outer peripheral side of the tip of the reamer main body is mutually connected as viewed from the direction facing the rake face. First, second, and third front cutting edges that intersect the obtuse angle are formed in order,
Among these, the flank of the first front cutting edge directed toward the tip side of the reamer main body has first and second flank faces whose flank angle increases stepwise as the distance from the first front cutting edge increases. The reamer insert characterized in that the flank face of the third front cutting edge directed toward the outer peripheral side of the reamer body has a single clearance angle.

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