JP5845816B2 - Tip replacement type cutting tool - Google Patents

Description

  The present invention relates to a tip-replaceable cutting tool in which a tip end of a tool body is detachable and replaceable.

  In a cutting tool such as an end mill, the cutting blade disposed at the tip of the cylindrical outer tool body is the most frequently used, and along with this, damage to the tool body becomes significant at the tip. For example, Patent Documents 1 and 2 propose a replacement type in which the tip of the main body is detachable. In the cutting tool described in Patent Document 1, a tool main body and a tool tip that is detachable and replaceable are fitted by a fitting convex part and a fitting concave part having a non-circular cross section, and the tool It is fastened by a screw member that is screwed from the tip side of the tip part, and in the cutting tool described in Patent Document 2, a key and a key hole are further formed in the fitting convex part and the fitting concave part having a circular cross section. The tool body and the tool tip are fastened together by screw members.

Japanese Utility Model Publication No. 5-78420 Japanese Utility Model Publication No. 5-88823

  However, in the cutting tools described in Patent Documents 1 and 2, only one screw member is screwed along the axis of the cylindrical tool body so as to detachably fasten the tool body and the tool tip. Therefore, in order to securely screw these tool body and tool tip part with sufficient fastening force so that the tool tip part does not fall off, the diameter of the screw member and screw hole must be increased naturally. Absent. As a result, the inner and outer diameters of the fitting irregularities must be increased, and as a result, the outer diameter (diameter) of the tool body and the replaceable tool tip is, for example, a relatively large diameter cutting of 50 mm or more. There was a problem that it could only be applied to tools.

  In such a cutting tool, a coolant hole is formed in the tool body so as to open toward the cutting edge, and at the time of cutting, coolant is supplied from the machine tool side to cool the cutting edge and the work material. Such coolant holes form a trunk hole along the axis of the tool body, and supply coolant by forming a branch hole from the trunk hole toward the cutting edge on the outer periphery of the tool body. However, when the screw member is screwed along the axis of the tool body as described above, a trunk hole may be formed on the tip side of the screw hole of the tool body. Therefore, it becomes difficult to supply coolant to the cutting edge of the replaceable tool tip.

  The present invention has been made under such a background, and can reliably hold the replaceable tool tip regardless of the outer diameter of the tool body, and can be detachable in this way. An object of the present invention is to provide a tip-replaceable cutting tool capable of supplying coolant to a cutting blade at the tip of the replaceable tool from a coolant hole along the axis of the tool body.

In order to solve the above problems and achieve such an object, according to the present invention, a chip discharge groove is formed on the outer periphery of an outer cylindrical tool body rotated around an axis, and the tool of the chip discharge groove is formed. A cutting edge is disposed on the outer peripheral side of the wall surface facing the rotation direction, and a tip discharge groove communicating with the chip discharge groove is formed at the tip of the tool body so as to face the tool rotation direction of the tip discharge groove. The tip of the replaceable tool having the tip cutting edge disposed on the outer peripheral side of the wall surface is spaced from the axis to the outer peripheral side in the radial direction at a distance in the circumferential direction, and the tip of the replaceable tool is located on the rear end side. A plurality of clamp screws inserted toward the tool body are screwed into the tool body to be detachably attached to the front end exchangeable cutting tool. First, the clamp screw is disposed on the rear end side. Radial outer peripheral side with respect to the axis as you go It is inserted into the tip of the replaceable tool so as to face and is screwed into the tool body, and secondly, the clamp screw is rearward in the tool rotation direction toward the rear end. And is inserted into the tip of the replaceable tool and screwed into the tool body, and thirdly, on the tip surface of the tool body and the rear end surface of the replaceable tool tip. A plurality of sets of keys and key grooves that can be fitted to each other are provided at intervals in the circumferential direction at positions spaced radially outward from the axis, and of these, two sets of keys adjacent in the circumferential direction Further, the circumferential interval of the key grooves is characterized in that at least one set interval is different from the other set interval .

  In the tip-replaceable cutting tool configured as described above, a plurality of clamp screws inserted into the tip of the replaceable tool at intervals in the circumferential direction at positions away from the axial line of the tool body in the radial direction are provided. By screwing into the tool body, the replaceable tool tip is fastened to the tool body and detachably attached, so that the fastening force for attaching the replaceable tool tip can be dispersed with these multiple clamp screws. it can. Accordingly, the diameter of each clamp screw and the screw hole into which the clamp screw is screwed can be reduced. Even if the outer diameter (diameter) of the tool body or the tip of the replaceable tool is a small diameter of, for example, 40 mm or less, the tool It is possible to replace the tip while securely holding the tip.

  In addition, since the clamp screw is inserted into the tool body at a position spaced apart from the tool body axis in the radial direction with a space in the circumferential direction, a coolant hole extending along the axis is formed in the tool body. In this case, a supply hole for supplying coolant to the tip cutting blade can be formed in the tip of the replaceable tool so as to communicate with the coolant hole. It is possible to reliably and sufficiently cool and lubricate the tip cutting edge disposed at the tip of the replaceable tool and the processing portion of the work material cut by the tip cutting edge.

  Further, particularly when the coolant hole extending along the axis line is formed in the tool body in this way, the clamp screw is provided at the tip of the replaceable tool so as to go to the outer peripheral side in the radial direction with respect to the axis line toward the rear end side. By inserting and screwing into the tool body, the screw hole at the tip of the tool body is also drilled toward the outer periphery in the radial direction toward the rear end. A large inner diameter can be secured, and a sufficient amount of coolant can be supplied to the tip of the replaceable tool.

  Furthermore, the clamp screw is configured to be inserted into the tip of the replaceable tool so as to go to the rear side in the direction of rotation of the tool as it goes toward the rear end, and is screwed into the tool main body. As described above, the screw hole can be drilled toward the outer peripheral side in the radial direction as it goes toward the rear end side, and clamped in the direction in which the cutting load acts on the tip of the replaceable tool during cutting in the circumferential direction. Since the screw is screwed in, the tip of the replaceable tool can be held more reliably.

  Further, a plurality of sets of keys and key grooves that can be fitted to each other are spaced apart in the circumferential direction at a position away from the axial line on the distal end surface of the tool body and the rear end surface of the replaceable tool distal end portion. By providing, the said cutting load of the circumferential direction at the time of cutting can be received more reliably, and a replaceable tool front-end | tip part can be hold | maintained. Of these, the circumferential spacing between two pairs of keys and key grooves adjacent in the circumferential direction is such that the spacing of at least one set is different from the spacing of the other set, so that the tip of the replaceable tool It is possible to prevent the tool body from being attached at the wrong position in the direction.

  As described above, according to the present invention, even if the outer diameter of the tool body or the replaceable tool tip is a small diameter, the tool tip can be reliably held and removed and replaced. Further, when a coolant hole is formed along the axis of the tool body, the coolant can also be supplied to the tip cutting edge of the replaceable tool tip to achieve efficient cooling and lubrication.

It is a perspective view which shows one Embodiment of this invention. It is a disassembled perspective view of the state which removed the exchangeable tool front-end | tip part in embodiment shown in FIG. It is a perspective view which shows the tool main body of embodiment shown in FIG. It is a front view of the tool main body shown in FIG. It is a perspective view of the exchangeable tool front-end | tip part of embodiment shown in FIG. It is a front view of the exchangeable tool front-end | tip part shown in FIG. It is a side view of the exchangeable tool front-end | tip part shown in FIG. It is a rear view of the exchangeable tool front-end | tip part shown in FIG. It is AA sectional drawing in FIG. FIG. 4 is a perspective view of a state in which a stopper plug is attached to the coolant hole of the tool body shown in FIG. 3. It is a disassembled perspective view of the state which removed the stopper plug from the state shown in FIG.

  FIGS. 1 to 11 show an embodiment in which the present invention is applied to a blade-end-changeable end mill. In the present embodiment, the tool body 1 is formed of a metal material such as a steel material and has an outer cylindrical shape centered on the axis O, and the end mill has a rear end side (see FIGS. 1 to 3, 10 and 11 is gripped by a spindle of a machine tool (not shown), and is rotated in the tool rotation direction T around the axis O, and is sent in a direction intersecting the axis O, thereby cutting the work material The cutting process is applied to the.

  On the outer periphery of the tool body 1, a plurality of (three in the present embodiment) chip discharge grooves 2 are provided at intervals in the circumferential direction, and open to the front end surface 1 </ b> A of the tool body 1 toward the rear end side. It is formed in a spiral shape so as to go to the rear side in the rotation direction T. In addition, on the outer peripheral side of the wall surface of the chip discharge groove 2 facing the tool rotation direction T, a plurality of (four in this embodiment, one chip discharge groove 2) insert mounting seats 3 are similarly provided on the tool body 1. As it goes to the rear end side, it is formed in a step shape so as to go to the rear side in the tool rotation direction T.

  And, in these insert mounting seats 3, a cutting insert 4 formed of a hard material such as cemented carbide causes its cutting edge (main cutting edge) 4 </ b> A to protrude to the outer peripheral side of the tool body 1, It is detachably attached by an insert attachment screw 5. Of these, the most advanced insert 4 is attached so that the auxiliary cutting edge 4B connected to the inner peripheral side of the cutting edge 4A protrudes slightly toward the tip side from the tip surface 1A of the tool body 1. .

  Further, a coolant hole 6 is formed in the tool body 1 so as to penetrate along the axis O, and the tool body 1 has a plurality of branch holes 6A with the coolant hole 6 along the axis O as a trunk hole. Branched radially outward. These branch holes 6 </ b> A are opened at the bottom of the chip discharge groove 2, and coolant can be supplied toward the cutting edge 4 </ b> A protruding to the outer peripheral side of the cutting insert 4.

  The front end surface 1A of the tool body 1 has a flat shape perpendicular to the axis O, and a chip discharge groove 2 and the most advanced insert mounting seat 3 are opened on the outer peripheral side, and a coolant hole 6 is opened in the center. It has been. Among these, in the opening portion of the coolant hole 6, a plurality of recessed portions 7 and 8 (three in this embodiment) are recessed so as to spread from the inner peripheral surface of the opening portion of the coolant hole 6 having a circular cross section to the outer peripheral side. However, it is formed in a petal shape as shown in FIG. 4 at intervals in the circumferential direction. Therefore, these recesses 7 and 8 are formed at positions away from the axis O of the tool body 1 toward the radially outer peripheral side.

  Of these recesses 7 and 8, every other recess 7 in the circumferential direction is a key groove provided in the present embodiment at a position spaced from the axis O toward the radially outer periphery with a spacing in the circumferential direction. The bottom surface 7A is perpendicular to the axis O and faces the front end side, and the wall surface 7B extends from the periphery of the bottom surface 7A to the front end side in parallel to the axis O. Further, a stopper plug mounting screw hole 7C is formed on the bottom surface 7A in parallel with the axis O.

  Further, as shown in FIG. 4 as viewed from the front end side in the direction of the axis O, the wall surface 7B has a 1/2 concave cylindrical surface with the outer peripheral side centered on the center line of the stopper plug mounting screw hole 7C. Has a substantially 1/4 convex cylindrical surface extending so as to contact the inner peripheral surface of the coolant hole 6 with a radius substantially equal to the concave cylinder formed on the outer peripheral side, and is in contact with both of the concave and convex cylindrical surfaces between the concave and convex cylindrical surfaces. A narrow plane is formed.

  In the present embodiment, the three recesses 7 have the same size, and are formed at the same position from the axis O to the radially outer peripheral side. However, the recess 7 of this embodiment that also serves as a key groove has at least a circumferential interval between two sets of recesses 7 adjacent in the circumferential direction, for example, a circumferential interval between centerlines of the stopper plug mounting screw holes 7C. One set is different from the other set. In particular, in this embodiment, the intervals in the circumferential direction between the adjacent recesses 7 forming three sets are all slightly different.

  On the other hand, every other three recesses 8 formed between these recesses 7 in the circumferential direction are also a bottom surface 8A facing the front end side in the same manner as the recess 7 and a wall surface extending from the periphery of the bottom surface 8A to the front end side. 8C, and a clamp screw hole 8C is formed on the bottom surface 8A. The center line of the clamp screw hole 8C is directed to the outer peripheral side toward the rear end side of the tool body 1. In particular, in this embodiment, it extends so as to be inclined toward the rear side in the tool rotation direction T toward the rear end side of the tool body 1. That is, the clamp screw hole 8C extends from the position away from the axial line O to the outer peripheral side in the radial direction, further toward the outer peripheral side, the bottom surface 8A is perpendicular to the center line of the clamp screw hole 8C, and the wall surface 8B is It is parallel to the center line of the clamp screw hole 8C.

  The wall surface 8B, when viewed in the direction of the center line of the clamp screw hole 8C, has an outer peripheral side having a 1/2 concave cylindrical surface centered on the center line of the clamp screw hole 8C, and an inner peripheral side of the wall surface 8B. The flat surface extends toward the opening of the coolant hole 6 in contact with the 1/2 concave cylindrical surface. In addition, in the present embodiment, these concave portions 8 are also equal in size to each other, are formed at equal positions from the axis O to the radially outer peripheral side, and the circumferential intervals are also equal to each other. .

  Furthermore, the coolant hole 6 has a circular shape with a constant inner diameter from the rear end of the tool body 1 to the vicinity of the front end surface 1A, and the inner diameter is slightly increased by one step at a position that does not reach the recesses 7 and 8 near the front end surface 1A. Thus, the inner circumferential surface forms a cylindrical hole-shaped fitting hole 6B having a constant inner diameter centered on the axis O, and further at the positions of the recesses 7 and 8 than the fitting hole 6B. Further, the inner diameter is formed so as to be slightly increased by one step. Further, between the coolant hole 6 and the opening on the tip side of the recesses 7 and 8 and the tip surface 1A of the tool body 1, the tip side opening of the recesses 7 and 8 is surrounded, except for the chip discharge groove 2 and the insert. A countersink 9 having a bottom surface perpendicular to the axis O is formed so as not to reach the mounting seat 3.

  The replaceable tool tip 11 attached to the tip of the tool body 1 is formed in a disk shape having substantially the same outer diameter with the same metal material as the tool body 1, and a chip discharge groove of the tool body 1 is provided on the outer periphery thereof. As will be described later, a tip discharge groove 12 that spirally communicates with each chip discharge groove 2 is formed with the replaceable tool tip 11 attached to the tip of the tool body 1 as will be described later. A tip insert mounting seat 13 that is continuous with the insert mounting seat 3 of the tool body 1 in a stepped manner is formed on the outer peripheral portion of the wall surface facing the tool rotation direction T side of the groove 12. Such a replaceable tool tip 11 is attached so as to be coaxial with the axis O of the tool body 1 and is detachably attached, and is rotated together with the tool body 1 in the tool rotation direction T, thereby inserting the tip insert. The cutting blade of the cutting insert attached to the mounting seat 13 is used for cutting the work material.

  Here, the cutting insert attached to the tip insert mounting seat 13 is the cutting insert 4 having the same shape and the same size as that attached to the tool body 1 in the present embodiment, and therefore the tip insert mounting seat 13 and the insert mounting screw 5 are the same. Is said to be the same shape and size. The tip insert mounting seats 13 are formed one by one in each tip discharge groove 12, and accordingly, the cutting inserts 4 to be attached are also one by one. And this cutting insert 4 makes the cutting edge (main cutting edge) 4A project as an end cutting edge on the outer peripheral side of the exchangeable tool tip 11 and the auxiliary cutting edge connected to the inner peripheral side of the end of the cutting edge 4A. 4B is detachably attached by the insert attachment screw 5 so as to protrude slightly toward the tip side from the tip surface of the replaceable tool tip portion 11.

  The rear end surface 11A of the replaceable tool front end portion 11 has a planar shape perpendicular to the axis O except for the central portion thereof, and the front end discharge groove 12 and the front end insert mounting seat 13 are opened. However, on the rear end surface 11A, the cutting insert in which the auxiliary cutting edge 4B is protruded from the front end surface 1A by being attached to the foremost end of the tool body 1 on the rear side in the tool rotation direction T of the opening of the front end insert mounting seat 13. A recess 11 </ b> B for avoiding interference with 4 is formed.

  An annular groove 11C centered on the axis O is formed at the center of the rear end face 11A, and an axis O protruding slightly toward the rear end from the rear end face 11A is formed inside the annular groove 11C. A disc-shaped seat portion 14 centering on the center portion, a fitting projection 15 projecting further from the seat portion 14 toward the rear end side, and a key 16 are formed integrally with the replaceable tool tip portion 11. Among these, the seat portion 14 has a seat surface 14 </ b> A facing the rear end side in a planar shape perpendicular to the axis O, and the projecting height from the rear end surface 11 </ b> A is from the tip surface 1 </ b> A of the tool body 1 to the countersink portion. 9, the outer diameter is smaller than the inner diameter of the countersink portion 9, and the rear end surface 11 </ b> A of the replaceable tool front end portion 11 is brought into close contact with the front end surface 1 </ b> A of the tool body 1. It can be accommodated in the counterbore part 9 in a state.

  Furthermore, the fitting protrusion 15 has a cylindrical shape centered on the axis O, and the outer diameter of the fitting protrusion 15 is in sliding contact with the inner peripheral surface of the fitting hole 6B of the coolant hole 6. The fitting projection 15 is fitted to the coolant hole 6 in a state where the rear end surface 11A of the replaceable tool tip 11 is brought into close contact with the tip surface 1A of the tool main body 1. By fitting with the hole 6B, the replaceable tool tip 11 is coaxially mounted on the tool body 1 as described above.

  Further, the keys 16 having the same size as the recesses 7 protrude from the base end portion of the fitting protrusion 15 to the outer peripheral side at the same position as the concave portions 7 and spaced from the axis O to the outer peripheral side in the radial direction. Each of the end surfaces 16A is formed in a planar shape perpendicular to the axis O and faces the rear end side, and a side surface 16B extending from the periphery of the end surface 16A to the front end side in parallel to the axis O. These keys 16 can be respectively fitted into the recesses 7 also serving as key grooves, that is, the circumferential intervals are made equal to the corresponding recesses 6, while two sets of adjacent keys in the circumferential direction are provided. The circumferential interval of 16 is different from the other groups in at least one set, and in particular, in this embodiment, the circumferential intervals between adjacent keys 16 that form three sets are all slightly different. It is said that.

  Further, the side surface 16B of the key 16 has an outer peripheral side edge portion of a 1/2 convex cylindrical surface whose outer peripheral side has a center line parallel to the axis O as seen from the rear end side in the axis O direction as a seat portion. 14 is formed in a shape that is cut out flush with the outer peripheral surface of 14, and the inner peripheral side is a substantially 1/4 concave cylindrical surface that extends so as to be in contact with the outer peripheral surface of the fitting projection 15 with a radius substantially equal to the convex cylindrical surface. A narrow plane that is in contact with both of the concave and convex cylindrical surfaces is formed between the concave and convex cylindrical surfaces, and when the fitting protrusion 15 is fitted into the fitting hole 6B, The side surface 16B of the key 16 is slidably contacted with the wall surface 8B of the corresponding concave portion 7 except for the portion notched with the outer peripheral surface of the seat portion 14, so that the key 16 fits into the concave portion 7 also serving as a key groove. Can be combined.

  The inner peripheral portion of the cylindrical fitting projection 15 is a blind hole that does not open to the distal end side of the replaceable tool distal end portion 11. However, from the hole bottom, the outer peripheral portion is directed toward the distal end side. A supply hole 17 extending toward the side and opening in the bottom surface of each tip discharge groove 12 is formed. As described above, the fitting protrusion 15 is fitted into the fitting hole 6B, and the key 16 is pressed. When the replaceable tool tip 11 is fitted to the tip of the tool body 1 by fitting into the recess 7 that also serves as a groove, these supply holes 17 are connected to the tool body 1 via the inner periphery of the fitting projection 15. The coolant is directed toward the cutting edge (main cutting edge) 4 </ b> A and the auxiliary cutting edge 4 </ b> B that are communicated with the coolant hole 6 of the cutting insert 4 attached to the tip insert mounting seat 13 of the tip discharge groove 12. Can be supplied.

  An annular groove 15A is formed on the outer peripheral surface of the fitting protrusion 15 at the position of the end face 16A of the key 16, and the fitting protrusion 15 has a fitting hole at the rear end side of the annular groove 15A. It is made to fit with the part 6B. Further, the height from the rear end face 11A, which is a plane perpendicular to the axis O, to the end face 16A of the key 16 is from the tip face 1A of the tool body 1 which is also a plane perpendicular to the axis O to the bottom face 7A of the recess 7. The fitting projections 15 are fitted into the fitting holes 6B, and the corresponding keys 16 are fitted into the recesses 7 so that the replaceable tool tip 11 is fitted to the tool body 1 tip. In a state of being mounted on the part, the rear end surface 11A of the replaceable tool front end portion 11 can be brought into close contact with the front end surface 1A of the tool body 1.

  On the other hand, a concave hole 11D having a circular cross section with the axis O as the center is formed in the central portion of the front end surface of the replaceable tool front end portion 11, and the rear end from the outer peripheral portion of the bottom surface facing the front end side of the concave hole 11D. To the side, the same number of clamp screw insertion holes 18 as the clamp screw holes 8C of the tool body 1 are formed, with the front end side being a large diameter hole 18A and the rear end side being a small diameter hole 18B coaxial with the large diameter hole 18A. It is formed at intervals in the circumferential direction and penetrates to the rear end side of the replaceable tool front end portion 11, and is opened between the keys 16 on the seat surface 14 </ b> A of the seat portion 14 in this embodiment. Accordingly, these clamp screw insertion holes 18 are also formed at positions away from the axis O toward the radially outer peripheral side.

  Further, the center lines of these clamp screw insertion holes 18 are arranged so that the fitting protrusions 15 are fitted into the fitting holes 6B and the corresponding keys 16 are fitted into the recesses 7 as described above. In a state where the replaceable tool tip 11 is mounted on the tool body 1 so that 11A is in close contact with the tip surface 1A, it is coaxial with the center line of the clamp screw hole 8C of the tool body 1. That is, in this embodiment, the clamp screw insertion hole 18 also extends toward the outer peripheral side as it goes toward the rear end side, and in particular, tilts toward the rear side in the tool rotation direction T as it goes toward the rear end side. It extends.

  When the replaceable tool tip 11 is mounted on the tool body 1 and the clamp screw insertion hole 18 and the clamp screw hole 8C are arranged coaxially in this way, the diameter is smaller than the large diameter hole 18A and larger than the small diameter hole 18B. By inserting a clamp screw 19 having a head portion 19A and a screw portion 19B having a smaller diameter than the small diameter hole 18B and screwed into the clamp screw hole 8C into the clamp screw insertion hole 18 from the concave hole 11D and screwing into the clamp screw hole 8C. The replaceable tool tip 11 is brought into close contact so that the rear end face 11A is pressed against the tip face 1A, is restrained in the direction of the axis O, and is detachably attached to the tip of the tool body 1.

  In the tip-replaceable cutting tool having the above-described configuration, a plurality of clamp screws 19 for attaching the replaceable tool tip 11 to the tool body 1 in this manner are spaced apart from each other in the circumferential direction, respectively, from the axis O of the tool body 1 in the radial direction. The tool screw is inserted into the clamp screw insertion hole 18 formed at a position distant from the outer peripheral side, and is screwed into the clamp screw hole 8C formed at a position distant from the axis O in the radial direction. The fastening force and strength required for each clamp screw 19 can be dispersed and reduced as compared with the case where one clamp screw is screwed along and the tip of the replaceable tool is attached.

  For this reason, since the screw diameter of each clamp screw 19 and the clamp screw hole 8C can be reduced, even when the outer diameter of the tool main body 1 or the replaceable tool tip 11 is small, the replaceable tool tip. 11 can be detachably attached to the tip of the tool body 1 to be replaceable. For example, when the tip of the replaceable tool is attached with one clamp screw, the outer diameter is limited to about 50 mm, although it depends on cutting conditions, etc., the outer diameter of the tip replaceable cutting tool having the above configuration is Even a tool of 40 mm or less can perform stable cutting while making the replaceable tool tip 11 removable.

  Moreover, even if the coolant hole 6 is formed along the axis O of the tool body 1 as in the present embodiment, the clamp screw 19 is screwed into a position distant from the axis O toward the outer peripheral side in the radial direction. The supply hole 17 for supplying the coolant to the tip cutting edge through a hole portion (in this embodiment, the inner peripheral portion of the cylindrical fitting protrusion 15) communicating with the coolant hole 6 on the axis O is replaced with an exchangeable tool. It becomes possible to form in the front-end | tip part 11. FIG. For this reason, also in the cutting insert 4 attached to the replaceable tool distal end portion 11, the cutting edge (main cutting edge) 4 </ b> A and the auxiliary cutting edge 4 </ b> B serving as the distal cutting edge and the cutting site of the work material cut by these Therefore, reliable and sufficient cooling can be achieved and more stable cutting can be performed.

  Further, in the present embodiment, the clamp screw 19 is inserted into the replaceable tool tip 11 and screwed into the tool body 1 so as to go to the outer peripheral side in the radial direction with respect to the axis O as it goes to the rear end side of the tool body 1. Accordingly, the clamp screw hole 8C of the tool body 1 is also formed obliquely so as to go to the radially outer peripheral side toward the rear end side. Accordingly, the distance from the coolant hole 6 can be increased on the rear end side of the clamp screw hole 8C, and thereby the inner diameter of the coolant hole 6 can be ensured, so that the cutting insert attached to the tool main body 1 can be secured. A sufficient amount of coolant for the cutting edge (main cutting edge) 4A and the auxiliary cutting edge 4B of the cutting insert 4 serving as the leading edge cutting edge of the replaceable tool tip 11 as well as the cutting edge 4 (main cutting edge) 4A. Can be supplied.

  In addition, the clamp screw 19 in the present embodiment is inclined so as to go to the rear side in the tool rotation direction T as it goes to the rear end side, and is inserted into the replaceable tool tip portion 11 and screwed into the tool body 1. . For this reason, the rear end face 11A is in close contact with the front end face 1A while the replaceable tool front end 11 is pressed to the rear side in the tool rotation direction T where the cutting load acts from the cutting edge 4A and the auxiliary cutting edge 4B during cutting. Therefore, it is possible to perform more stable cutting by improving the attachment rigidity.

  In the present embodiment, the rear end surface 11A of the replaceable tool front end portion 11 and the front end surface 1A of the tool body 1 are provided with a plurality of sets of keys 16 that can be fitted to each other and a recess 7 that also serves as a key groove from the axis O. It is formed at a position distant from the outer peripheral side in the radial direction with an interval in the circumferential direction, and the exchangeable tool tip 11 is prevented from rotating with respect to the tool body 1 by fitting the key 16 and the recess 7. Can be attached stably.

  Then, as described above, the clamp screw 19 is inclined and screwed toward the rear side in the tool rotation direction T as it goes to the rear end side, so that the key 16 of the replaceable tool front end portion 11 is rearward in the tool rotation direction T. Since it is fitted so as to be pressed against the wall surface 7B of the concave portion 7 toward the side, it is possible to prevent rattling or the like from occurring at the tip end portion 11 of the replaceable tool and to promote more stable cutting. .

  Furthermore, in this embodiment, three sets of recesses 7 that also function as keys 16 and key grooves that can be fitted to each other are formed, and of these, the two sets of keys 16 and recesses 7 that are adjacent to each other in the circumferential direction. The interval in the direction is such that at least one set interval is different from the other set intervals, and in particular, all set intervals are different. For this reason, the key 16 that does not correspond to the circumferential interval cannot be fitted into the recess 7, and is disposed on the outer peripheral side of the tool body 1 and the replaceable tool tip 11 to prevent chatter vibration, for example. When the circumferential intervals of the rows of cutting blades (main cutting blades) 4A are set to be unequal intervals, the cutting blade 4A of the replaceable tool tip 11 is circumferential with respect to the rows of cutting blades 4A of the tool body 1. It is possible to prevent the replaceable tool tip 11 from being attached so as to be in a wrong position in the direction.

  Further, in the present embodiment, the fitting hole portion formed in the coolant hole 6 of the tool body 1 in addition to the fitting between the key 16 and the concave portion 7 also serving as the key groove and the fastening by screwing the clamp screw 19. The fitting main body 1 and the replaceable tool tip 11 can be integrated with high attachment rigidity by fitting the fitting protrusion 15 formed on the replaceable tool tip 11 into 6B. Then, by fitting the fitting hole 6B having a circular cross section with the axis O as the center and the fitting projection 15 into the tool main body 1, the replaceable tool tip 11 is as high as about ± 0.05 mm or less, for example. It can be attached with the same degree of coaxiality, and cutting with high accuracy can be achieved.

  By the way, in the present embodiment, as described above, the replaceable tool tip 11 is detachably attached to the tip of the tool body 1 by the clamp screw 19 and used for cutting. For example, the depth of cut is not large. In some cases, it is also possible to perform cutting with only the tool body 1 without attaching the replaceable tool tip 11. However, if cutting is performed with the replaceable tool tip 11 simply removed, the coolant flows out from the opening of the coolant hole 6 in the tip surface 1A of the tool body 1 when the coolant is supplied to the coolant hole 6. End up.

  Therefore, in such a case, the stopper plug 20 is fixed to the stopper plug 20 as shown in FIGS. 10 and 11 by using the stopper plug mounting screw hole 7C formed in the recess 7 which also serves as the key groove of the tool body 1. What is necessary is just to attach to the front-end | tip part of the tool main body 1 with the attachment screw 21 so that attachment or detachment is possible, and to seal the opening part of the coolant hole 6. Here, as shown in FIG. 11, the stopper plug 20 has a cylindrical shaft portion 20A that can be fitted into the fitting hole 6B with an outer diameter equal to that of the fitting projection 15 of the replaceable tool tip 11. Thus, in a state where the shaft portion 20A is fitted in the fitting hole portion 6B, the shaft portion 20A is closely adhered to the bottom surface of the countersink portion 9 opened to the tip surface 1A of the tool body 1 and is accommodated in the countersink portion 9. A flat plate-shaped sealing portion 20B is integrally formed, and the sealing portion 20B has the same number as the recesses 7 so as to be coaxial with the center lines of the stopper plug mounting screw holes 7C of the plurality of recesses 7, respectively. A tapered stopper mounting screw insertion hole 20 </ b> C that is gradually reduced in diameter toward the rear end side is formed.

  Accordingly, such a stopper plug 20 is fitted with the shaft portion 20A in the fitting hole 6B as described above and the sealing portion 20B is accommodated in the counterbore portion 9 and brought into close contact with the bottom surface, The stopper plug mounting screw 21 having a countersunk head inserted into each stopper plug mounting screw insertion hole 20C is fixed by screwing it into the stopper plug mounting screw hole 7C of the recess 7 so that the fitting by the shaft portion 20A and the sealing portion 20B are performed. Due to the close contact with the bottom surface of the counterbore 9, the opening of the coolant hole 6 to the front end surface 1A is sealed. For this reason, even if it supplies coolant, it does not flow out from this opening part, but it can supply coolant reliably to the cutting edge 4A of the cutting insert 4 attached to the tool main body 1 from the said branch hole 6A of the coolant hole 6. FIG. it can.

  In the above-described embodiment, the present invention is applied to a blade-tip replaceable end mill in which the cutting blade 4A and the auxiliary cutting blade 4B are formed on the cutting insert 4 that is detachably attached to the tool body 1 and the replaceable tool tip 11. Although the case has been described, for example, a solid end mill in which a cutting blade is integrally formed on the tool body and the replaceable tool tip, or a tool tip and a replaceable tool tip by brazing or the like on which the cutting blade tip on which the cutting blade is formed is brazed. It is also possible to apply the present invention to a brazing tool or the like that is joined to the steel plate.

DESCRIPTION OF SYMBOLS 1 Tool body 1A Tip surface of tool body 1 2 Chip discharge groove 3 Insert mounting seat 4 Cutting insert 4A Cutting edge (main cutting edge)
6 Coolant hole 6A Branch hole 6B Fitting hole 7 Recess (key groove)
7C Stopper mounting screw hole 8 Recess 8C Clamp screw hole 9 Countersink part 11 Replaceable tool tip 11A Rear end face of replaceable tool tip 11 12 Tip discharge groove 13 Tip insert mounting seat 15 Fitting protrusion 16 Key 17 Supply Hole 18 Clamp screw insertion hole 19 Clamp screw 20 Stopper plug O Tool axis 1 axis T Direction of rotation of tool body 1 during cutting

Claims (4)

A chip discharge groove is formed on the outer periphery of a cylindrical cylindrical tool body that is rotated around the axis, and a cutting blade is disposed on the outer peripheral side of the wall surface of the chip discharge groove facing the tool rotation direction. At the tip of the tool, a tip discharge groove communicating with the chip discharge groove is formed, and an exchangeable tool tip having a tip cutting edge disposed on the outer peripheral side of the wall facing the tool rotation direction of the tip discharge groove is Removable by inserting a plurality of clamp screws inserted into the tip of the replaceable tool toward the rear end side at a distance in the circumferential direction at a position distant from the axis radially outward Attached to the
The clamp screw is inserted into the replaceable tool tip so as to go to the outer peripheral side in the radial direction with respect to the axis as it goes to the rear end, and is screwed into the tool body. Cutting tools. A chip discharge groove is formed on the outer periphery of a cylindrical cylindrical tool body that is rotated around the axis, and a cutting blade is disposed on the outer peripheral side of the wall surface of the chip discharge groove facing the tool rotation direction. At the tip of the tool, a tip discharge groove communicating with the chip discharge groove is formed, and an exchangeable tool tip having a tip cutting edge disposed on the outer peripheral side of the wall facing the tool rotation direction of the tip discharge groove is Removable by inserting a plurality of clamp screws inserted into the tip of the replaceable tool toward the rear end side at a distance in the circumferential direction at a position distant from the axis radially outward Attached to the
The clamping screw is inserted into the replaceable tool tip to face the rear side of the tool rotation direction toward the rear side, the distal end portion replaceable, characterized in that screwed to the tool body Cutting tools. A chip discharge groove is formed on the outer periphery of a cylindrical cylindrical tool body that is rotated around the axis, and a cutting blade is disposed on the outer peripheral side of the wall surface of the chip discharge groove facing the tool rotation direction. At the tip of the tool, a tip discharge groove communicating with the chip discharge groove is formed, and an exchangeable tool tip having a tip cutting edge disposed on the outer peripheral side of the wall facing the tool rotation direction of the tip discharge groove is Removable by inserting a plurality of clamp screws inserted into the tip of the replaceable tool toward the rear end side at a distance in the circumferential direction at a position distant from the axis radially outward Attached to the
The front end surface of the tool body and the rear end surface of the replaceable tool front end portion are spaced apart in the circumferential direction by a plurality of sets of keys and key grooves that can be fitted to each other at positions radially away from the axis. Among these, the circumferential interval between two sets of keys and key grooves adjacent to each other in the circumferential direction is characterized in that at least one set interval is different from the other set intervals. A tip-replaceable cutting tool. A coolant hole extending along the axis is formed in the tool body, and a supply hole that communicates with the coolant hole and supplies coolant to the tip cutting edge is formed at the tip of the replaceable tool. tip replaceable cutting tool as claimed in any one of claims 1 to 3, characterized in that.

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