JP2013052461A - Indexable thread milling cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly screw a plurality of fixing screws into a body so that an indexable tip can be securely fixed to the body even when a thread cutting tooth is an inclined tooth or a helical tooth.SOLUTION: An indexable tip 14 is fixed to a body 12 by using a non-penetration type fixing screw 30, being screwed into the body 12 at the front side of a tip mounting groove 20 without penetrating through the indexable tip 14 and a penetration type fixing screw 32, penetrating through the indexable tip 14 to be screwed into the body 12 at the other side across the tip mounting groove 20. Accordingly, in a small-diameter thread milling cutter 10 with an outer diameter of 23 mm or less having a helical tooth as a thread cutting tooth 22, the pair of fixing screws 30 and 32 can be properly screwed into the body 12, so that the indexable tip 14 can be securely fixed to the body 12 by the fixing screws 30 and 32.

Description

  The present invention relates to a thread cutting mill, and in particular, an indexable type in which an indexable chip (corresponding to a throwaway chip defined in JIS) provided with a thread cutting blade is detachably mounted on a body by a plurality of mounting screws. The present invention relates to an improvement in thread cutting milling.

  (a) A chip mounting groove provided in the axial direction on the outer peripheral surface of the body, and (b) A large number of protrusions are provided at regular intervals in the longitudinal direction while being detachably inserted into the chip mounting groove. An indexable tip provided with a concavo-convex thread cutting blade along one edge of the plurality of ridges, and (c) a plurality of screwing points spaced in the axial direction of the body, and the tip mounting groove A plurality of mounting screws that are screwed into the body from the side that intersects and faces the cutting rotation direction, and presses the indexable chip against the groove side surface of the chip mounting groove to integrally fix it. Indexable threading milling is known. The thread cutting mill described in Patent Document 1 is one example, and a plurality of mounting screws are screwed to the body in front of the chip mounting groove without penetrating the indexable chip, and the tip portion is an indexable chip. It comes into contact with and presses.

Special table 2003-503219 gazette

  However, in such a conventional indexable threading cutter, when the thread cutting blade is inclined or twisted with respect to the axis O of the body, the indexable tip is inclined with respect to the axis O along with the inclination or twist. If this is done, the thickness of the body on both sides of the chip mounting groove will change in the axial direction, so it may not be possible to secure sufficient thickness and strength to screw the mounting screw, especially in small-diameter thread milling cutters. It was. Even when the thickness of the indexable tip is changed with the inclination or twisting of the thread cutting blade, the thickness and strength sufficient to screw the mounting screw by changing the thickness of the body accordingly. May not be secured. In addition, if it is restricted to be an inclined blade or a twisted blade in this way, and it is restricted to a straight blade (straight blade), a large cutting load acts because the uneven thread cutting blade cuts into the work material at once, and the tool In addition, the load on the machine increases and the durability is impaired, and the machined surface roughness may deteriorate due to vibration or the like.

  The present invention has been made in the background of the above circumstances, and its purpose is to install a plurality of mounting tips so that the indexable tip can be securely fixed to the body even when the thread cutting blade is an inclined blade or a twist blade. The purpose is to enable the screw to be properly screwed into the body.

  In order to achieve such an object, the first invention comprises: (a) a chip mounting groove provided in the axial direction on the outer peripheral surface of the body; and (b) removably inserted into the chip mounting groove, and An indexable tip provided with a plurality of ridges at regular intervals in the direction and provided with a concavo-convex thread cutting blade along one edge of the ridges, and (c) spaced apart in the axial direction of the body At the plurality of screwing locations, the body is screwed into the body from the side crossing the chip mounting groove and facing the cutting rotation direction, and the indexable chip is pressed against the groove side surface of the chip mounting groove. And (d) the thread cutting blade is inclined or twisted with respect to the axis O of the body, and (e) the plurality of mounting screws. Said the in A non-penetrating screw that is screwed to the body on the front side of the chip mounting groove without penetrating the chipable chip, and a screw that is threaded to the body on the opposite side through the indexable chip and sandwiching the chip mounting groove And a through screw to be joined.

  The second invention is the indexable threading milling machine according to the first invention, wherein (a) the tip mounting groove is provided inclined with respect to the axis O of the body, and the thickness of both sides sandwiching the tip mounting groove is (B) The through screw is used in a portion where the thickness on the opposite side is relatively thick in the axial direction across the tip mounting groove as viewed from the screwed side of the mounting screw. The non-penetrating screw is used in a portion where the thickness on the opposite side across the chip mounting groove is relatively thin in the axial direction.

  According to a third aspect of the present invention, in the indexable thread milling cutter of the first or second aspect of the invention, the threaded portion where the through screw is used has a diameter larger than that of the head of the through screw on the front side of the tip mounting groove. An insertion hole is provided, and the indexable tip is provided with a through hole having a diameter smaller than that of the head, and the head is brought into contact with the peripheral portion of the through hole so that the indexable tip is It is characterized by being pressed against the side surface of the chip mounting groove.

  The fourth invention is the indexable thread cutting milling machine according to any one of the first to third inventions, wherein (a) the thread cutting blade is a twist blade, and the twist direction of the twist blade and the rotation direction of cutting seen from the shank side are (B) The through screw is used as the mounting screw on the front end side of the body, and the non-through screw is used as the mounting screw on the shank side.

  The fifth invention is the indexable thread cutting milling machine according to any one of the first to third inventions, wherein (a) the thread cutting blade is a twist blade, and the twist direction of the twist blade and the cutting rotation direction viewed from the shank side are In contrast, (b) the non-through screw is used as the mounting screw on the front end side of the body, and the through screw is used as the mounting screw on the shank side.

  A sixth aspect of the present invention is the indexable thread milling cutter according to any one of the first to fifth aspects of the present invention. (A) The tip mounting groove has an inclination angle θ with respect to the axis O of the body of 0 ° <θ ≦ 20 °. (B) the indexable tip is straight with a constant width dimension so as to be fitted into the chip mounting groove. (C) The thread cutting blade has a twist with a twist angle of 3 ° to 23 ° in a state where the indexable chip is mounted in the chip mounting groove. It is a blade.

  A seventh aspect of the present invention is the indexable thread milling cutter of any one of the first to sixth aspects, wherein the outer diameter of the thread cutting blade is in the range of 10 mm to 23 mm, and the pitch is in the range of 0.5 mm to 3 mm. It is characterized by.

  In such an indexable threading milling machine, a non-penetrating screw that is screwed into the body on the front side of the chip mounting groove without penetrating the indexable chip, and a chip mounting groove that penetrates the indexable chip. Since a plurality of mounting screws are configured to have a through screw that is screwed to the body on the opposite side, the thread cutting blade is an inclined blade or a twisting blade, and the outer diameter is a small diameter of about 23 mm or less, for example Also in the thread milling, the plurality of mounting screws can be appropriately screwed to the body, and the indexable chip can be securely fixed to the body with a predetermined mounting strength by using these mounting screws. As a result, the cutting load is reduced as compared with the straight blade, the load on the tool and the machine is reduced, the durability is improved, and the vibration is suppressed to obtain a good machined surface roughness.

  The second invention is a case where the chip mounting groove is provided to be inclined with respect to the axis O of the body, and the thicknesses on both sides sandwiching the chip mounting groove are continuously changed in the axial direction. A through screw is used in the portion where the thickness on the opposite side is relatively thick in the axial direction across the tip mounting groove when viewed from the screw side of the screw, and the thickness on the opposite side across the tip mounting groove is relative in the axial direction. Non-penetrating screws are used in thin parts. For this reason, the indexable chip can be securely fixed to the body with a predetermined mounting strength by appropriately screwing the mounting screw into the body regardless of the change in the thickness of the body accompanying the inclination of the chip mounting groove. .

  According to a third aspect of the present invention, an insertion hole having a diameter larger than that of the head of the through screw is provided in front of the chip mounting groove at the screwing location where the through screw is used. A through-hole having a smaller diameter is provided, and the indexable tip is pressed by the head of the through-hole being brought into contact with the peripheral edge of the through-hole. That is, at the screwing location where the through screw is used, it is possible to press the head in contact with the indexable chip simply by providing an insertion hole having a larger diameter than the head of the through screw. Simple and inexpensive construction.

  According to a fourth aspect of the present invention, when the thread cutting blade is a twisting blade and the twisting direction of the twisting blade is the same as the cutting rotation direction viewed from the shank side, a through screw is used as a mounting screw on the tip end side of the body. Since non-penetrating screws are used as mounting screws on the side, regardless of changes in the thickness of the body, multiple mounting screws are properly screwed into the body to ensure that the indexable tip is securely fixed to the body with a predetermined mounting strength. can do.

  The fifth invention is a case where the thread cutting blade is a twist blade, and the twist direction of the twist blade is opposite to the cutting rotation direction seen from the shank side, and a non-through screw is used as a mounting screw on the tip side of the body. Since a through screw is used as the mounting screw on the side, regardless of changes in the thickness of the body, a plurality of mounting screws are appropriately screwed into the body to securely fix the indexable chip to the body with a predetermined mounting strength. be able to.

  In the sixth invention, the chip mounting grooves are provided in a straight line with a constant width dimension at a constant inclination angle θ in the range of 0 ° <θ ≦ 20 °, and a straight longitudinal shape is formed with a constant width dimension. Since the indexable tip is fitted and fixed in the tip mounting groove, the twist angle of the thread cutting blade is twisted at a constant angle within the range of 3 ° to 23 °, so that the straight simple shape Even when this indexable tip is used, it is possible to appropriately obtain the effect of reducing the cutting load by using a thread cutting blade as a twist blade.

  The seventh invention is a case where the outer diameter of the thread cutting blade is within the range of 10 mm to 23 mm and the pitch is within the range of 0.5 mm to 3 mm, and the mounting screw is mounted on the chip when the thread cutting blade is an inclined blade or a twist blade. When trying to screw into only one side of the groove, insufficient thickness and insufficient strength will be a problem, but by using through screws and non-through screws as mounting screws, the indexable tip is properly fixed to the body be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the indexable thread cutting mill which is one Example of this invention, (a) is a top view, (b) is a front view, (c) is the bottom view seen from the front end side (right side of figure) of (b) FIG. FIG. 2 is a cross-sectional view of the indexable thread milling cutter of FIG. 1, where (a) is an enlarged cross-sectional view taken along the line IIA-IIA in FIG. 1 (b), and (b) is a cross-sectional view taken along the line IIB-IIB in FIG. It is an expanded sectional view of a part. FIG. 2 is a view independently showing the indexable tip of the indexable threaded milling cutter of FIG. 1, wherein (a) is a plan view, (b) is a front view, (c) is a right side view, and (d) is a perspective view. It is a figure explaining the processing method of the internal thread by the indexable type threading milling cutter of FIG. 1, and the figure which showed together the cutting load of a triaxial direction. It is the figure which showed the cutting load (combined force) of the indexable thread cutting mill of FIG. 1 compared with the case of the thread cutting mill of a straight blade. FIG. 5 is a perspective view showing an embodiment in which the present invention is applied to a two-blade indexable thread milling cutter in which a pair of indexable tips are provided symmetrically with respect to an axis O. FIG. 4 is a diagram showing an embodiment in which the present invention is applied to a right-turning threading mill provided with a left-handed threading blade, where (a) is a plan view, (b) is a front view, and (c) is a tip of (b). It is the bottom view seen from the side (right side of a figure).

  The indexable threading milling machine of the present invention is driven by an NC machining center or the like so as to be rotated around an axis and reciprocated relative to a screw material (workpiece) in the axial direction. Various screws and female screws having different diameters can be cut using a single tool. The internal thread cutting may be a bottomed blind hole or a through hole.

  In addition, only the thread groove is machined by the convex part of the thread cutting blade, and the inner peripheral surface of the pilot hole forms the top of the female screw thread as it is, or the outer peripheral surface of the cylindrical material remains as it is of the male screw thread. The top of the peak may be formed, but the bottom between the ridges may also contribute to the cutting process, and may have a total cutting edge that performs the cutting process including the top of the thread.

  The screw cutting blade is preferably a twisting blade having a constant twist angle, but may be an inclined blade inclined at a constant inclination angle over the entire length with respect to the axis O of the body. These twist angles and inclination angles may be slightly changed in the axial direction. The present invention is preferably applied when the chip mounting groove is inclined with respect to the axis O. However, even if the chip mounting groove is parallel to the axis O, one side surface of the groove is inclined. The present invention can also be applied when the thickness of the body continuously changes in the axial direction.

  In the second invention, a through screw is used in a portion where the thickness on the opposite side of the mounting screw is relatively thick in the axial direction as viewed from the screwing side of the mounting screw, and the opposite thickness across the chip mounting groove. Non-penetrating screws are used in parts where the thickness is relatively thin in the axial direction, but conversely, it is also possible to define using the wall thickness on the screwing side (front side) of the mounting screw. In this case, a non-through screw may be used in a relatively thick portion, and a through screw may be used in a portion where the wall thickness is relatively thin in the axial direction. When three or more mounting screws are used, the intermediate mounting screw is appropriately determined as a through screw or a non-through screw depending on the thickness.

  In the third invention, an insertion hole having a diameter larger than that of the head of the through screw is provided in front of the chip mounting groove at the screwing location where the through screw is used. The front side portion of the mounting groove may be greatly cut away to expose the side surface of the indexable chip from the body, and a through screw may be directly inserted into the through hole of the indexable chip.

  The fourth invention relates to a threaded milling cutter in which the twisting direction of the twisting blade is the same as the cutting rotation direction viewed from the shank side, specifically, right-handed, right-handed, left-handed or left-handed. The fifth aspect of the invention relates to a threading milling cutter in which the twisting direction of the twisting blade is opposite to the cutting rotation direction viewed from the shank side, specifically, right-handed, left-handed, left-handed, or right-handed. Also in the fourth and fifth inventions, when three or more mounting screws are used, the intermediate mounting screw is appropriately determined as a through screw or a non-through screw depending on the thickness.

  In the fourth and fifth inventions, the thread cutting blade is a twisted blade, but the same can be applied to an inclined blade inclined at a constant angle with respect to the axis O. That is, when the inclination direction of the thread cutting blade is the same as the cutting rotation direction seen from the shank side, it is fixed using a through screw on the front end side of the body and fixed using a non-through screw on the shank side. To do. In addition, when the inclination direction of the thread cutting blade is opposite to the cutting rotation direction seen from the shank side, the tip end side of the body is fixed using a non-penetrating screw, and the shank side is fixed using a penetrating screw. You can do it.

  In the sixth invention, the inclination angle θ with respect to the axis O of the chip mounting groove is 20 ° or less. For example, in the case of an indexable chip having an outer diameter of about 23 mm or less, if the inclination angle θ exceeds 20 °, the axial direction It becomes difficult to secure a sufficient length. When forming a twisted blade on a straight indexable tip, the twist angle is slightly larger than the inclination angle θ of the indexable tip, and it is desirable to determine it within a range of 3 ° to 23 °. In the sixth aspect of the invention, the thread cutting blade is provided with a constant twist angle. However, the twist angle may be continuously changed in the axial direction when other inventions are implemented. It is also possible to apply to a threading miller having an outer diameter larger than 23 mm. The inclination angle θ of the chip mounting groove is set to exceed 20 °, or the helix angle of the thread cutting blade is set to exceed 23 °. You can also

  In the seventh invention, the outer diameter of the thread cutting blade is in the range of 10 mm to 23 mm and the pitch is in the range of 0.5 mm to 3 mm, and the present invention is particularly preferably applied to such a small diameter indexable threading milling cutter. However, the present invention can also be applied to an indexable thread milling machine in which the outer diameter of the thread cutting blade exceeds 23 mm or the pitch exceeds 3 mm. In addition, the diameter dimension of the internal thread and the external thread that can be processed using such an indexable threading milling cutter is appropriately determined regardless of the diameter dimension of the indexable threading milling mill.

  The indexable tip is composed of a hard tool material such as high-speed tool steel or cemented carbide, for example. If necessary, a compound coating such as TiN, TiCN, TiAlN, CrN or DLC (Diamond Like Carbon; diamond) Or a hard coating such as a diamond coating, or a water vapor treatment or a nitriding treatment. As the body, a relatively inexpensive tool material such as tool steel is used.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a view showing an indexable threading milling cutter 10 (hereinafter simply referred to as a threading milling cutter 10) according to an embodiment of the present invention, where (a) is a plan view viewed from a direction perpendicular to the axis O, and (b). (A) is a front view seen from below, (c) is a bottom view seen from the tip side (right side of the figure) of (b). 2 is a cross-sectional view of the threaded milling cutter 10 of FIG. 1, where (a) is an enlarged cross-sectional view taken along the line IIA-IIA in FIG. 1 (b), and (b) is IIB − in FIG. 1 (b). It is an expanded sectional view of the IIB arrow part. 3 is a view independently showing the indexable tip 14 of the threaded milling cutter 10 of FIG. 1, wherein (a) is a plan view, (b) is a front view, (c) is a right side view, (d) (B) is a perspective view seen from diagonally upward on the right side of FIG.

  The thread milling cutter 10 is used by integrally fixing an indexable tip 14 to a body 12, and the body 12 includes a large-diameter cylindrical shank 16 held by a main shaft such as a machining center, A small-diameter cylindrical tip mounting portion 18 to which the dextable tip 14 is attached is integrally provided concentrically in the axial direction. On the outer peripheral surface of the chip mounting portion 18, there is provided a chip mounting groove 20 having a constant width and a rectangular cross section (right-angled quadrilateral) so as to be inclined with respect to the axis O at a predetermined inclination angle θ. The indexable chip 14 having a certain width and a straight longitudinal shape is detachably fitted into the chip mounting groove 20 so as to be integrally fixed. The inclination angle θ is set to a constant angle within a range of 0 ° <θ ≦ 20 °. The tip mounting groove 20 opens at the tip of the tool, and one end of the indexable tip 14 protrudes slightly from the body 12 toward the tip.

  The indexable tip 14 is provided with a large number of ridges at regular intervals in the longitudinal direction, and a concavo-convex thread cutting blade 22 is formed along one end edge of the ridges. The thread cutting blade 22 is a right-twisted twist blade whose twist angle is a constant angle within a range of 3 ° to 23 ° in a state where the indexable chip 14 is mounted in the chip mounting groove 20. A rake face 24 is provided along the surface, and cutting is performed by being rotated clockwise around the axis O as viewed from the shank 16 side. The present embodiment relates to a small-diameter thread milling cutter in which the outer diameter of the thread cutting blade 22 is in the range of 10 mm to 23 mm and the pitch is in the range of 0.5 mm to 3 mm. The indexable chip 14 is made of a cemented carbide and is coated with a hard coating such as TiN, TiCN, TiAlN, or CrN as necessary. The body 12 is made of a relatively inexpensive tool material such as high-speed tool steel.

  The indexable chip 14 is integrally fixed to the chip mounting part 18 by a pair of mounting screws 30 and 32 at a pair of screwing points spaced apart in the axial direction of the chip mounting part 18. Yes. The mounting screws 30 and 32 are screwed into the chip mounting portion 18 from the side crossing the chip mounting groove 20 and facing the cutting rotation direction, in other words, from the rake face 24 side of the indexable chip 14. The insertable chip 14 is pressed and fixed integrally to one groove side surface 20f of the chip mounting groove 20, that is, the opposite side (right side groove surface in FIG. 1 (c)) when viewed from the screwing side of the mounting screws 30 and 32. . Thus, in FIG. 1C, when cutting is performed by being rotated counterclockwise about the axis O, the direction of the cutting force applied to the indexable tip 14 (clockwise direction) and the mounting screw 30 , 32 coincides with the direction pressed by the mounting screws 30, 32, and the fixed state by the mounting screws 30, 32 is maintained satisfactorily regardless of the cutting resistance, and rattling or displacement of the indexable tip 14 is suppressed.

  The screwing mode of the mounting screws 30 and 32 into the chip mounting portion 18 is different. That is, since the chip mounting groove 20 is inclined at an inclination angle θ with respect to the axis O, the thickness on both sides sandwiching the chip mounting groove 20 continuously changes in the axial direction. In order to allow the mounting screws 30 and 32 to be screwed with a predetermined strength irrespective of the change in thickness, the side opposite to the chip mounting groove 20 when viewed from the screwing side of the mounting screws 30 and 32 (in FIG. 1 (c) The indexable chip 14 is penetrated in the thick part on the right side of the chip mounting groove 20 and screwed into the opposite part, and the indexable chip 14 is penetrated in the part with the thin thickness on the opposite side. Without being done, it is screwed into the front side portion of the chip mounting groove 20.

  Specifically, one mounting screw 30 located on the shank 16 side where the opposite wall thickness is relatively thin penetrates the indexable chip 14 as clearly shown in FIG. Without being connected, the tip mounting portion 18 is screwed to the tip mounting portion 18 on the front side, and the tip end portion 34 is brought into contact with the front side surface 36 of the indexable tip 14 so that the indexable tip 14 is brought into contact with the side surface of the groove. Press to 20f. A screw hole 38 is provided in the front side of the chip mounting portion 18 of the chip mounting portion 18 (left side of the chip mounting groove 20 in FIG. 2A), and the mounting screw 30 is screwed together, while the tip The portion 34 has a truncated tapered shape, and a front side surface 36 of the indexable tip 14 is provided with a bottomed tapered recess 40 at the same taper angle. The attachment position of the indexable chip 14 with respect to the chip mounting portion 18 is defined by the engagement. In the present embodiment, the tip 34 and the tapered recess 38 are slightly eccentric (for example, about 0.05 mm to 0.3 mm) in a state where the indexable chip 14 is mounted in the chip mounting groove 20, and the taper is caused by the taper. The indexable tip 14 is pressed by the bottom surface of the tip mounting groove 20 (lower wall surface in FIG. 2 (a)) by the wedge action, and the end surface on the shank 16 side (left end in FIGS. 1 (a) and 1 (b)). Surface). That is, in FIG. 1B, a pressing force is applied toward the lower left direction of the mounting screw 30. The mounting screw 30 corresponds to a non-through screw.

  The other mounting screw 32 located on the distal end side in the axial direction having a relatively thick wall on the opposite side is penetrated through the indexable tip 14 as clearly shown in FIG. By being screwed onto the chip mounting portion 18 on the opposite side across the mounting groove 20, the tapered portion 46 provided on the head 44 is brought into contact with the indexable chip 14, and the indexable chip 14. Is pressed against the groove side surface 20f. A screw hole 48 is provided on the opposite side (right side of the chip mounting groove 20 in FIG. 2B) across the chip mounting groove 20 when viewed from the screwing side of the mounting screw 32, and the screw shaft 50 of the mounting screw 32 is provided. Is inserted into the front side of the tip mounting groove 20 (the left side of the tip mounting groove 20 in FIG. 2B). The insertion hole 52 has a larger diameter than the head 44 of the mounting screw 32. , And the head 44 is allowed to be inserted into the insertion hole 52 and contact the indexable chip 14. The indexable tip 14 is provided with a through hole 54 having a diameter smaller than that of the head 44 and larger than that of the screw shaft 50, and the above-mentioned taper is provided at the opening peripheral portion on the side where the screw shaft 50 is inserted. A tapered surface 56 is provided at the same taper angle as the portion 46, and the attachment position of the indexable tip 14 with respect to the tip mounting portion 18 is defined by the engagement between the tapered portion 46 and the tapered surface 56. In the present embodiment, the tapered portion 46 and the tapered surface 56 are slightly eccentric (for example, about 0.05 mm to 0.3 mm) in a state where the indexable chip 14 is mounted in the chip mounting groove 20, and the wedge due to the taper. As a result, the indexable tip 14 is pressed against the bottom surface of the tip mounting groove 20 (the lower wall surface in FIG. 2B) and the end surface on the shank 16 side (the left end surface in FIGS. 1A and 1B). ). That is, in FIG. 1B, a pressing force is applied toward the lower left direction of the mounting screw 32. The mounting screw 32 corresponds to a through screw.

  FIG. 4 is a diagram for explaining a machining method when the internal thread 62 is cut on a predetermined workpiece 60 by using the thread cutting mill 10 according to the present embodiment. Is prepared in advance. Then, the thread cutting mill 10 is mounted on an NC machining center or the like and inserted into the pilot hole 64, and is driven to rotate around the axis O as indicated by an arrow A, and the inner part of the pilot hole 64 is indicated by an arrow B. The female thread 62 is cut by the thread cutting blade 22 by being lead-feeded in the axial direction while revolving along the peripheral surface.

FIG. 5 is a diagram showing a comparison of the result of measuring and comparing the cutting load (the resultant force) when female threading was performed under the following processing conditions using the conventional threaded milling cutter 10 and the straight blade of this example. . The cutting load (the resultant force) is the resultant force of the cutting loads Fx, Fy, and Fz in the triaxial directions shown in FIG. 4, and according to the threading milling cutter 10 of the present embodiment, the threading blade 22 gradually moves from the tool tip side. Since cutting is performed by cutting into the workpiece 60, the peak value is greatly reduced although the time width of the cutting load (the resultant force) is widened. As a result, the burden on the tool or machine is reduced, the durability is improved, and the vibration is suppressed to obtain a good machined surface roughness. FIG. 5 is data of cutting load (combined force) for about 2 rotations.
(Processing conditions)
Tool diameter: φ13.5
Twist angle: 15 ° (product of the present invention), 0 ° (conventional product)
Workpiece material: S45C
Internal thread: M16 × 1.5
Screw stand length: 20mm
Pilot hole diameter: φ14.5
Cutting speed: 50 m / min
Feeding speed per tooth: 0.03mm / t
Cutting oil: Water-soluble cutting fluid Used machine: Vertical machining center

  Thus, according to the thread cutting mill 10 of the present embodiment, the non-penetrating mounting screw 30 that is screwed to the body 12 on the near side of the chip mounting groove 20 without penetrating the indexable chip 14; The indexable chip 14 is fixed to the body 12 using a through-type mounting screw 32 that penetrates the indexable chip 14 and is screwed to the body 12 on the opposite side across the chip mounting groove 20. For this reason, even in the small-diameter screw milling cutter 10 in which the thread cutting blade 22 is a twist blade and the outer diameter is 23 mm or less, the pair of mounting screws 30 and 32 can be appropriately screwed to the body 12. The indexable tip 14 can be securely fixed to the body 12 with a predetermined mounting strength by the mounting screws 30 and 32. As a result, the cutting load is reduced as compared with the straight blade, the load on the tool and the machine is reduced, the durability is improved, and the vibration is suppressed to obtain a good machined surface roughness.

  Further, in this embodiment, the chip mounting groove 20 is provided to be inclined with respect to the axis O of the body 12, and the thickness on both sides sandwiching the chip mounting groove 20 continuously changes in the axial direction. In this case, a through-type mounting screw 32 is provided at a portion where the thickness on the opposite side with respect to the tip mounting groove 20 as viewed from the screwing side of the mounting screws 30 and 32 is relatively thick in the axial direction (the tool tip side in the embodiment). A non-penetrating mounting screw 30 is used in a portion where the thickness on the opposite side of the chip mounting groove 20 is relatively thin in the axial direction (in the embodiment, on the shank 16 side). For this reason, regardless of the change in the thickness of the body 12 due to the inclination of the chip mounting groove 20, the mounting screws 30 and 32 are appropriately screwed into the body 12 to ensure that the indexable chip 14 has a predetermined mounting strength. It can be fixed to the body 12.

  In addition, at the screwing location where the through-type mounting screw 32 is used, an insertion hole 52 having a diameter larger than the head 44 of the mounting screw 32 is provided in front of the chip mounting groove 20, and the indexable chip 14. A through hole 54 having a diameter smaller than that of the head portion 44 is provided, and the indexable tip 14 is pressed against the groove side surface 20f by the head portion 44 being brought into contact with the peripheral portion of the through hole 54. That is, at the screwing location where the penetration type mounting screw 32 is used, the head 44 is brought into contact with the indexable chip 14 only by providing the insertion hole 52 having a diameter larger than that of the head 44 of the mounting screw 32. It can be pressed and configured easily and inexpensively.

  Further, in this embodiment, when the thread cutting blade 22 is a twist blade, the twist direction (right twist) of the twist blade is the same as the cutting rotation direction (right turn) viewed from the shank 16 side. Since a penetrating attachment screw 32 is used on the tip side and a non-penetrating attachment screw 30 is used on the shank 16 side, a pair of attachments is provided regardless of changes in the thickness of the body 12 due to the inclination of the tip attachment groove 20. The indexable tip 14 can be securely fixed to the body 12 with a predetermined mounting strength by screwing the screws 30 and 32 into the body 12 appropriately.

  Further, in this embodiment, the chip mounting groove 20 is provided in a straight line with a constant width dimension at a constant inclination angle θ within a range of 0 ° <θ ≦ 20 °, and a straight longitudinal shape with a constant width dimension. The indexable tip 14 forming the shape is fitted into the tip mounting groove 20 and fixed, so that the twist angle of the thread cutting blade 22 is twisted at a constant angle within a range of 3 ° to 23 °. Therefore, even when the straight simple indexable tip 14 is used, the effect of reducing the cutting load by using the thread cutting blade 22 as a twist blade can be appropriately obtained.

  In this embodiment, since the outer diameter of the thread cutting blade 22 is in the range of 10 mm to 23 mm and the pitch is in the range of 0.5 mm to 3 mm, the mounting screws 30 and 32 are used when the thread cutting blade 22 is a twisted blade. If the screw is to be screwed into only one side of the chip mounting groove 20, insufficient thickness or insufficient strength becomes a problem. However, by adopting the non-penetrating mounting screw 30 and the penetrating mounting screw 32, the index is increased. The insertable tip 14 can be appropriately fixed to the body 12.

  Next, another embodiment of the present invention will be described. In the following embodiments, parts that are substantially the same as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  The indexable threading mill 70 shown in FIG. 6 is a two-blade threading milling machine, and a pair of indexable chips 14 are attached to the chip mounting portion 18 of the body 12 symmetrically with respect to the axis O. ing. These indexable chips 14 are fixed to the body 12 using a pair of non-penetrating and penetrating mounting screws 30 and 32, respectively, as in the above-described embodiment. Note that the relative size of the pair of indexable chips 14 with respect to the body 12 is smaller than that of the above-described embodiment, and the indexable chips 14 can be disposed at the symmetrical positions with the axis O interposed therebetween without interfering with each other. ing.

  The indexable thread milling cutter 80 in FIG. 7 is provided with a left-twisted thread cutting blade 82 and is driven to rotate clockwise around the axis O when viewed from the shank 16 side. The portion 18 is provided with a tip mounting groove 84 inclined in the left direction in a straight line, and a linear indexable tip 86 having the thread cutting blade 82 is fitted into the tip mounting groove 84. The fixing screws 88 and 90 are integrally fixed to the body 12. In this embodiment, the wall thickness on the opposite side (the right side in FIG. 7 (c)) across the chip mounting groove 84 when viewed from the screwed side of the mounting screws 88, 90 is shank in the axial direction as opposed to the previous embodiment. Since the thickness increases toward the 16th side, the mounting screw 88 at the screwing location on the shank 16 side where the thickness is thicker penetrates through the indexable tip 86 and is screwed to the opposite side portion in the same manner as the mounting screw 32. A through screw is used. Further, with respect to the mounting screw 90 at the screwed portion on the tool tip side, which is thin on the opposite side across the chip mounting groove 84, the chip mounting groove does not penetrate through the indexable chip 86 as in the case of the mounting screw 30. A non-penetrating screw that is screwed into a portion on the near side from 84 is used. Thus, regardless of the change in the thickness of the body 12 due to the inclination of the chip mounting groove 84, the mounting screws 88 and 90 are appropriately screwed into the body 12 to ensure that the indexable chip 86 has a predetermined mounting strength. It can be fixed to the body 12.

  That is, in this embodiment, the twisting direction (left-handed twist) of the thread cutting blade 82 is opposite to the cutting rotational direction (right-turned) viewed from the shank 16 side, and the non-penetrating mounting screw 90 is provided on the tip side of the body 12. , And a through-type mounting screw 88 is used on the shank 16 side, so that the pair of mounting screws 88 and 90 are appropriately attached to the body 12 regardless of the change in the thickness of the body 12 due to the inclination of the chip mounting groove 84. Thus, the indexable chip 86 can be securely fixed to the body 12 with a predetermined mounting strength.

  As mentioned above, although the Example of this invention was described in detail based on drawing, these are one Embodiment to the last, This invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.

  10, 70, 80: Indexable threading miller 12: Body 14, 86: Indexable tip 20, 84: Tip mounting groove 20f: Groove side surface 22, 82: Screw cutting blade 30, 90: Mounting screw (non-penetrating screw) 32 , 88: Mounting screw (through screw) 44: Head 52: Insertion hole 54: Through hole O: Center axis θ: Inclination angle

Claims (7)

A chip mounting groove provided in the axial direction on the outer peripheral surface of the body;
An insert in which a plurality of ridges are provided in the chip mounting groove in a detachable manner at regular intervals in the longitudinal direction, and a concavo-convex thread cutting blade is provided along one edge of the plurality of ridges. Dexable chips,
At a plurality of screwing points spaced apart in the axial direction of the body, the indexable chip is screwed to the body from the side crossing the chip mounting groove and facing the cutting rotation direction. A plurality of mounting screws that are pressed against and fixed to the groove side surface;
In an indexable threading milling machine having
The thread cutting blade is inclined or twisted with respect to the axis O of the body,
The plurality of mounting screws include a non-penetrating screw that is screwed into the body in front of the chip mounting groove without penetrating the indexable chip, and the chip mounting through the indexable chip. An indexable thread milling machine comprising: a through thread screwed into the body on the opposite side across the groove. The chip mounting groove is provided to be inclined with respect to the axis O of the body, and the thickness on both sides sandwiching the chip mounting groove is continuously changing in the axial direction.
The through screw is used in a portion where the thickness on the opposite side across the tip mounting groove is relatively thick in the axial direction when viewed from the screwing side of the mounting screw, and the thickness on the opposite side across the tip mounting groove 2. The indexable thread milling machine according to claim 1, wherein the non-through screw is used in a relatively thin portion in the axial direction. In the screwing location where the through screw is used, an insertion hole having a diameter larger than that of the head of the through screw is provided on the front side of the chip mounting groove, and the indexable tip is formed on the indexable tip than the head. The small-diameter through hole is provided, and the indexable chip is pressed against the groove side surface of the chip mounting groove by causing the head portion to abut on the peripheral edge of the through hole. The indexable threading miller according to 1 or 2. The thread cutting blade is a twist blade, the twist direction of the twist blade and the cutting rotation direction seen from the shank side are the same,
The said penetration screw is used as the said attachment screw in the front end side of the said body, The said non-penetration screw is used as this attachment screw in the shank side. The any one of Claims 1-3 characterized by the above-mentioned. Indexable threading milling machine. The thread cutting blade is a twist blade, and the twist direction of the twist blade is opposite to the cutting rotation direction viewed from the shank side,
The non-penetrating screw is used as the mounting screw on the tip side of the body, and the penetrating screw is used as the mounting screw on the shank side. Indexable threading milling machine. The chip mounting groove is provided in a straight line with a constant width dimension so that an inclination angle θ with respect to the axis O of the body is inclined at a constant angle within a range of 0 ° <θ ≦ 20 °.
The indexable chip has a straight longitudinal shape with a certain width dimension so as to be fitted into the chip mounting groove,
The screw cutting blade is a twisting blade having a constant twisting angle in a range of 3 ° to 23 ° in a state where the indexable tip is mounted in the chip mounting groove. The indexable threading milling cutter according to any one of -5. The indexable thread cutting mill according to any one of claims 1 to 6, wherein an outer diameter of the thread cutting blade is in a range of 10 mm to 23 mm, and a pitch is in a range of 0.5 mm to 3 mm.

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