JP2017192991A - Cutting tip, tip holder, cutting tool set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tip in which chattering is hard to occur even if accuracy of positioning of a tooth point is high and a cutting resistance is high, and a tip holder.SOLUTION: A cutting tip for cutting a relatively moving external work-piece has a columnar body, and a cutting part which is positioned at an end of the body and includes a tooth point. On each of peripheral surfaces which are positioned on both outer sides in a width direction of a rake face of the tooth point in the body, a partial cylindrical area, which has a virtual center shaft parallel to a longer direction of the body, is formed. On the peripheral surface which is positioned on at least one of both outer sides in a relative rake direction of the tooth point in the body, a pair of inclined planes, which extend in the longer direction of the body, are formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cutting tip, a tip holder, and a cutting tool set that are particularly effective for threading of both screw bodies.

  Conventionally, as a cutting tip (chip, bite) for cutting a screw, a throw-away tip (throw-away bite) is used particularly for mass production using an NC lathe (see Patent Document 1).

  FIG. 23A shows an example of a thread-away throw-away tip and its holder. FIG. 23 (A) is a top view of a state in which the thread-cutting throw-away tip is attached to the holder. In this case, the throw-away tip 130 is screwed to the tip holder 120, and when the cutting edge is worn or chipped, it is not reground but disposable. When fixing to the dedicated chip holder 120, it is not necessary to adjust the center height again, so that replacement is easy and efficient especially when mass-producing with an NC lathe or the like.

  FIG. 23B is a perspective view of the throw-away tip 130 alone. The thickness B of the tip is usually 1 cm or less, and the tip is projected from the outer periphery of the tip holder 120 and attached.

JP-A-8-257837

  However, in order to cut accurately, a cutting tip and a tip holder (bite holder) capable of cutting with less chatter than before are required. Further, for example, in a conventional thread cutting tip or the like, the plan view of the cutting tip as a whole has a three-point blade structure with each apex portion having a substantially triangular shape, and the root of each blade portion. The part is provided with a V-shaped notch-shaped countersink blade structure, and the thread shape and dimensions to be formed by cutting are limited. Therefore, it is necessary to replace the chip for each dimension or for each target nominal diameter, and for cutting There has been a problem that the thread shape formed by a small amount of wear of the cutting edge at the time of machining changes every moment, and a precise thread shape cannot be formed continuously. In view of such circumstances, the present invention has high blade tip positioning accuracy and is less prone to chatter even when cutting resistance is high, while expanding the target nominal diameter and dimension range that can be handled with one cutting tip, An object of the present invention is to provide a cutting tip (tip) and a tip holder capable of continuously cutting a highly accurate screw thread shape and the like even when worn every moment.

  The present invention for solving the above problems is a cutting tip for performing a cutting process on a relatively moving external workpiece, and has a columnar main body, and a blade portion that is positioned at an end of the main body and has a cutting edge. The cutting tip according to claim 1, wherein a pair of inclined surfaces extending in the longitudinal direction of the main body are formed on a peripheral surface located on at least one of both outer sides of the cutting edge in the relative scooping direction of the main body. .

  In relation to the cutting tip, the present invention provides a virtual central axis that is parallel to the longitudinal direction of the main body on each of the peripheral surfaces of the main body that are located on both outer sides in the width direction of the rake face of the cutting edge. A partial cylinder or a columnar region is formed.

  In relation to the cutting tip, the present invention is characterized in that the pair of inclined surfaces are more in a radial direction than an arc locus on an extension line of a partial arc that is a cross section perpendicular to the longitudinal direction of the main body of the partial cylinder or columnar region. It is formed inside.

  In the present invention, the pair of inclined surfaces are formed symmetrically with respect to a reference line extending from the tip of the blade edge in the relative scooping direction when viewed from the longitudinal direction of the main body. It is characterized by that.

  In relation to the cutting tip, the present invention is characterized in that the centers of curvature of at least the pair of partial cylinders or columnar regions coincide with each other.

  In relation to the cutting tip, the present invention is such that the blade portion is formed at one end in the longitudinal direction of the main body, and the main body is engaged with one of the external member and the longitudinal direction of the main body. It has a possible positioning surface.

  In relation to the cutting tip, the present invention is such that the blade portion is formed at both ends in the longitudinal direction of the main body, and the main body can be engaged with one of the external member and the longitudinal direction of the main body. It has a 1st positioning surface and the 2nd positioning surface which can be engaged with the other of the said external member and the said main body longitudinal direction, It is characterized by the above-mentioned.

  In relation to the cutting tip, the present invention is such that the tip of the cutting edge in the blade portion has a symmetrical shape with respect to a reference line extending in the longitudinal direction of the main body when viewed from the relative scooping direction. Features.

  In relation to the cutting tip, the present invention is characterized in that the front clearance angle of the cutting edge is 10 ° or more.

  The present invention that solves the above-described problem is a cutting tip that performs cutting on a relatively moving external workpiece, and a rake side abutting surface that can abut against an external member serving as a holder in a relative rake direction of the cutting edge. A cutting tip having an anti-rake side contact surface capable of contacting an external member serving as the holder on the side opposite to the relative rake direction.

  In relation to the cutting tip, the present invention has a positioning surface that contacts the external member in the protruding direction of the blade edge.

  In connection with the cutting tip, the present invention provides a partial cylindrical or columnar region in which each of the rake side contact surface and the anti-rake side contact surface has a virtual central axis that is parallel to the longitudinal direction of the main body. It is characterized by including.

  In relation to the cutting tip, the present invention is characterized in that both the rake side contact surface and the anti-rake side contact surface are provided by a single partial cylinder or columnar region. .

  In relation to the cutting tip, the present invention is characterized by being obtained by processing from a cylindrical material.

  The present invention for solving the above-mentioned problems is a tip holder capable of holding a cutting tip at the tip of the holder body, and the cutting tip is accommodated in the tip of the holder body with the blade edge exposed. It is a chip holder characterized by having an accommodation hole.

  In relation to the above-mentioned chip holder, the present invention provides a pair of housing holes extending in a direction parallel to the axial direction of the housing hole on an inner peripheral surface located on at least one of both sides in the width direction of the virtual rake face. An inclined surface is formed.

  In connection with the chip holder, the present invention provides a partial cylindrical or columnar region having a virtual central axis parallel to the axial direction of the receiving hole on the inner peripheral surface located on both sides in the width direction of the virtual rake face. Is formed.

  In relation to the chip holder, the present invention provides the partial arc trajectory in which the pair of inclined surfaces have a cross section perpendicular to the virtual central axis of the partial cylinder or columnar region formed on the inner periphery of the accommodation hole. It is characterized by being formed radially inward.

  In relation to the chip holder, the present invention is characterized in that the pair of inclined surfaces are formed symmetrically with respect to the virtual central axis of the receiving hole when viewed from the axial direction.

  In relation to the chip holder, the present invention is characterized in that the centers of curvature of at least the pair of partial cylinders or columnar regions coincide with each other.

  In relation to the above-mentioned tip holder, the present invention has a bolt hole penetrating to the accommodation hole on the outer peripheral surface of the holder body facing the inclined surface, and the cutting tip is fastened and fixed by the bolt. And

  In relation to the above-mentioned tip holder, the present invention is characterized in that the holder body is provided with a hole for extruding the cutting tip in the direction parallel to the axis of the receiving hole toward the cutting edge of the cutting tip. To do.

  In relation to the chip holder, the present invention is characterized in that the receiving hole has a receiving surface facing in a relative scooping direction.

  In relation to the chip holder, the present invention is characterized in that the holder body has a positioning surface that can be engaged with one of the cutting chip and the holder body in the longitudinal direction.

  In relation to the above-mentioned tip holder, the present invention provides a lower jaw portion for receiving the blade portion of the cutting tip, which is continuous with the lower surface of the receiving hole, and from the distal end portion of the holder body to the cutting tip. It is formed to protrude in the longitudinal direction.

  In relation to the chip holder, the present invention is characterized in that the axial direction of the accommodation hole is perpendicular to the longitudinal direction of the holder body.

  In relation to the chip holder, the present invention is characterized in that the axial direction of the accommodation hole is parallel to the longitudinal direction of the holder body.

  This invention which solves the above-mentioned subject is a cutting tool set which combined the above-mentioned cutting tip described in any of the above, and the above-mentioned tip holder described in any of the above.

  According to the present invention, by combining with the tip holder that can fix the cutting tip without loosening, it is possible to provide a cutting tool with less chatter and high blade tip positioning accuracy. In addition, according to the cutting tip or cutting tool of the present invention, while expanding the target nominal diameter and dimension range that can be handled by one blade, the thread shape that is continuously highly accurate even if it is worn from moment to moment, etc. The effect that it becomes possible to cut is obtained.

(A) It is a perspective view of the cutting tip which concerns on 1st embodiment of this invention. (B) It is sectional drawing of the state which combined the chip | tip for cutting which concerns on 1st embodiment of this invention, and a chip | tip holder. (A) It is a top view of the cutting tip which concerns on 1st embodiment of this invention. (B) It is a bottom view of the cutting tip which concerns on 1st embodiment of this invention. (C) It is a side view of the cutting tip which concerns on 1st embodiment of this invention. (A) It is a perspective view of the chip holder which concerns on 2nd embodiment of this invention. (B) In the chip holder which concerns on 2nd embodiment of this invention, it is sectional drawing of the accommodation hole vicinity part which accommodates the cutting chip in a front-end | tip. (C) It is an enlarged view of the accommodation hole of the chip holder which concerns on 2nd embodiment of this invention. (A) It is a top view of the chip holder which concerns on 2nd embodiment of this invention. (B) It is a bottom view of the chip holder which concerns on 2nd embodiment of this invention. (C) It is CC 'arrow sectional drawing in FIG. 4 (A) of the chip holder which concerns on 2nd embodiment of this invention. (A) It is a perspective view of the state where the cutting tip concerning a first embodiment of the present invention was inserted in the tip holder. (B) It is sectional drawing of the state which inserted the chip | tip for cutting which concerns on 1st embodiment of this invention in the chip holder. It is explanatory drawing explaining a series of flows when the chip | tip for cutting which concerns on 1st embodiment of this invention is extruded from a chip | tip holder, and is taken out. (A) It is a side view of the chip holder for internal thread processing based on 4th embodiment of this invention for fixing the chip | tip for cutting when performing internal thread cutting. (B) It is an enlarged view of the accommodation hole which accommodates the chip | tip for cutting in the chip | tip holder for internal thread processing. (C) It is CC 'arrow sectional drawing in FIG. 7 (A) of the tip holder part for internal thread processing. (A) It is a perspective view of the state which inserted the chip | tip for cutting in the chip | tip holder for internal thread processing which concerns on 5th embodiment of this invention. (B) It is BB 'arrow sectional drawing in FIG. 8 (A) of the cutting tool set which is 5th embodiment of this invention. In a cutting tool set concerning a fifth embodiment of the present invention, it is explanatory drawing explaining a series of flows when a cutting tip is pushed out from a tip holder for female thread processing. (A) It is a side view of the external thread part of both screw bodies. (B) It is explanatory drawing of a screw thread when a male screw body is seen in the central axis perpendicular | vertical direction of a screw. It is (A) front view of the fastening structure of the external thread body and internal thread body cut with the cutting tool of this embodiment, (B) is a top view. It is (A) front sectional drawing of the fastening structure, and (B) side sectional drawing. (A) is a front sectional view of the female screw body, and (B) is a front sectional view of the female screw body whose spiral direction is opposite to that of the female screw body. It is (A) front view of the same male screw body, (B) Sectional drawing of only a screw thread, (C) Plan view. It is the (A) side view of the same male screw body, (B) Sectional drawing of only a screw thread, (C) Top view. (A) is sectional drawing which expands and shows the cross-sectional shape of the screw thread of the same male screw body, (B) is sectional drawing which expands and shows the cross-sectional shape of the screw thread of the same female screw body. (A) is a matrix showing a verification external thread group used in the screw design method according to the embodiment of the present invention, and (B) is a verification internal thread group used in the screw design method according to the embodiment of the present invention. It is a matrix which shows. It is a figure which shows the aspect of the fastening strength test of the external thread body for the verification, and the internal thread body for the verification. It is a graph which shows the result of the fastening strength test of the external thread body for the verification of the nominal diameter N16, and the internal thread body for the verification. It is a graph which shows the result of the fastening strength test of the external thread body for the verification of the nominal diameter N24, and the internal thread body for the verification. It is a graph which shows the result of the fastening strength test of the external thread body for the verification of the nominal diameter N30, and the internal thread body for the verification. It is a front view sectional view of the fastening structure of the external thread body and internal thread body concerning other examples. (A) It is a conceptual diagram of the use aspect of the conventional throw-away tip for thread cutting. (B) It is a perspective view of the conventional throw-away tip for thread cutting.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 9 are examples of embodiments for carrying out the present invention, and in the drawings, the same reference numerals denote the same components. In addition, in this figure and each subsequent figure, a part of structure is abbreviate | omitted suitably and drawing is simplified. And in this figure and each subsequent figure, the magnitude | size, shape, thickness, etc. of a member are exaggerated suitably and expressed.

  FIG. 1 illustrates a cutting tip (chip, bite) according to a first embodiment of the present invention. As shown in the perspective view of FIG. 1A, the chip 1 according to the present embodiment includes a main body 3 that is a columnar main body, and blades 2L1 and 2L2 that are located at the ends of the main body and have cutting edges. The The material of the chip 1 is preferably a cemented carbide having an excellent balance between hardness and stickiness. Other materials include high speed steel and cermet, and the blade portion may be coated with, for example, diamond, DLC, DIA, DG, TiC, TiN, TiCN, TiAlN, CrN, SiC, or the like.

  Partial cylindrical regions 3A each having a virtual center axis parallel to the chip body longitudinal direction Y are formed on the circumferential surfaces located on both outer sides in the width direction X of the rake face 2A of the cutting edge 2B in the main body 3 (see FIG. 1 (B)), a pair of inclined surfaces 4 extending in the longitudinal direction Y of the chip body are formed on the peripheral surface of the chip body located on at least one of the outer sides in the relative rake direction X of the cutting edge 2B. The centers of curvature C of the pair of partial cylindrical regions 3A coincide with each other.

  FIG. 1B shows a cross-sectional view of a state in which the chip 1 and a holder for housing the chip are combined. The pair of inclined surfaces 4 are formed on the chip body 3 in the direction opposite to the relative scoop direction Z. The pair of inclined surfaces 4 are formed on the radially inner side with respect to the arc locus 3B on the extension line of the partial arc that is a cross-section perpendicular to the chip body longitudinal direction Y of the partial cylindrical region 3A. The chip 1 according to the present embodiment can be easily created by grinding a round cutting tool. In the cross-sectional view of FIG. 1B, for convenience, the chip holder hole of the chip holder is shown outside the chip 1, but the inner periphery of the chip holder hole and the outer periphery of the chip 1 have substantially the same shape. As will be described later, the inclined surface (not shown) of the chip holder included in the chip receiving hole and the inclined surface 4 of the chip 1 are in contact with each other, so that the position of the cutting edge 2B of the chip 1 is accurately determined with respect to the holder 5.

  2A is a top view of the chip 1 according to the embodiment of the present invention, FIG. 2B is a bottom view of the chip 1, and FIG. 2C is a side view of the chip 1. . The tip 1 is formed with blade portions 2L1, 2L2 at both ends in the longitudinal direction L of the tip body. The tip shape of the blade edge 2B of the blade portions 2L1, 2L2 is a V-shape that is symmetrical with respect to a reference line extending in the chip body longitudinal direction Y when viewed from the relative scoop direction Z. Of course, although not particularly limited, the cutting edge 2B includes two main cutting edges 2D1 and 2D2 symmetrically.

  In FIG. 2A, the rake face 2A of the blade portions 2L1 and 2L2 is not particularly provided with a structure. However, in order to process chips generated when turning a workpiece in turning, grooves and protrusions are used. A structure may be provided as a chip breaker. Further, although no structure is provided on the upper surface of the main body 3 in FIG. 2A, a horizontal plane extending in the longitudinal direction Y of the chip body is formed, and a vertically downward force is transmitted when fastening from the upper part of the chip 1 is fixed. It may be configured so that the cause of chatter and the like is further eliminated.

  As shown in the bottom view of FIG. 2B, a bottom 6 is provided between the pair of inclined surfaces 4. A cross section of the bottom 6 is formed as an arc locus 3B (see FIG. 1B) on the extension line of the partial arc. Therefore, the chip 1 is inserted into the chip receiving hole 35 of the holder while being guided in the longitudinal direction L of the main body by the bottom portion 6, and the pair of inclined surfaces 4 and the inclined surfaces of the chip holder 5 are used to rotate the main spindle of the cutting apparatus. The blade portions 2L1 and 2L2 are accurately positioned in the orthogonal directions (here, the width direction X of the rake face 2A and the relative rake direction Z). The bottom surface 6 may be formed with a plane extending in the chip body longitudinal direction Y.

  As shown in FIG. 2 (C), between the blade edge 2B and the main body 3, a first positioning surface 15L1 that can be engaged with one of the external member (specifically, the chip holder) and the chip main body longitudinal direction Y, And the 2nd positioning surface 15L2 engageable with an external member and the other of the main body longitudinal direction Y is formed. A workpiece in the chip body longitudinal direction Y of the chip 1 due to the back force of the cutting resistance by contacting a positioning surface 15L1, 15L2 with a holder side positioning surface 60 provided in a chip receiving hole 35 of the chip holder 25 described later. And can prevent the reverse shift.

  In addition, the front clearance angle A of the blade edge 2B is set to 10 ° or more in order to prevent interference with the workpiece during internal thread hole machining, which will be described later. The heights of the positioning surfaces 15L1 and 15L2 (the height here is along the relative scoop direction Z, but the height direction varies depending on the position where the positioning surfaces 15L1 and 15L2 are formed) It is preferably set to 40% or less of the maximum outer dimension of the part 3 in the same height direction, and more desirably set to 25% or less. Similarly, the heights of the positioning surfaces 15L1 and 15L2 are preferably set to 50% or less of the maximum outer dimension of the heights in the same direction of the blade portions 2L1 and 2L2, and more preferably set to 30% or less. In any case, by setting the height of the positioning surfaces 15L1 and 15L2 small, it is possible to secure a large height in the same direction of the blade portions 2L1 and 2L2, and greatly increase the rigidity of the blade portions 2L1 and 2L2. Can do.

  In FIG. 3, a chip holder (tool holder) according to a second embodiment of the present invention will be described.

FIG. 3A shows a perspective view of the chip holder 25 according to the second embodiment of the present invention.
The tip holder 25 is mainly composed of a columnar shank portion 27, a tip receiving hole 35 at an end of the shank portion 27, a lower jaw portion 40 provided at the lower portion thereof, a bolt hole 30 of a fastening bolt, and the like. The cutting tool set is configured by inserting and fixing the chip 1 according to the first embodiment of the present invention inside the chip receiving hole 35. At this time, as shown in FIG. 4C, the lower end 2C of the cutting edge 2B of the tip 1 is supported by the protruding end 40B of the support surface 40A of the lower jaw 40. With this support structure, the chip 1 can be prevented from being shaken by a main component force that is a vertically downward component force of the cutting force. The support surface 40 </ b> A of the lower jaw portion 40 is formed so as to continue from the lower surface of the chip accommodation hole 35 in the axial direction L and further protrude from the shank portion 27.

  FIG. 3B shows a cross-sectional view in a direction perpendicular to the tip holder body axial direction L at the tip of the tip holder 25 according to the second embodiment of the present invention. An enlarged view of the chip accommodation hole 35 is shown in FIG. When it is assumed that a chip is inserted into the chip receiving hole 35, a partial cylindrical region 42A is formed on the inner peripheral surface located on both sides in the width direction X of the virtual rake face of the chip. The center of curvature of the partial cylindrical region 42A coincides with a virtual central axis C that is parallel to the axial direction of the chip receiving hole 35. A pair of inclined surfaces 45 extending in parallel with the virtual central axis C of the chip receiving hole 35 are formed on the inner peripheral surface located on at least one of both sides in the relative scooping direction H. The pair of inclined surfaces 45 are more radial than the partial arc locus 42B on the extension line of the partial cylindrical region 42A in a cross section perpendicular to the virtual central axis of the partial cylindrical region 42A formed on the inner periphery of the chip receiving hole 35. Formed inside. The inclined surface 45 of the chip holder is formed symmetrically with respect to the virtual center axis of the chip receiving hole 35, and the centers of curvature of the pair of partial cylindrical regions 42A coincide with the virtual center axis C. Further, the chip holder 25 according to the second embodiment has a bolt hole 30 penetrating from the outer peripheral surface of the shank portion 27 to the chip housing hole 35 at a location facing the inclined surface 45 of the chip housing hole 35. The chip 1 is fastened and fixed to the bolt hole 30 by screwing a tightening screw 70 from the outside and projecting it into the chip receiving hole 35.

  FIG. 4A shows a top view of the chip holder 25 according to the second embodiment of the present invention. A lower jaw portion 40 is provided at the end of the shank portion 27 in the axial direction so as to protrude. The lower jaw part 40 supports the lower part 2C of the cutting edge 2B of the tip 1 in the traveling direction of the cutting edge 2B with respect to the workpiece. Further, a bolt hole 30 and a chip push-out hole 50 are provided in the vicinity of the end of the shank portion 27 in the axial direction. The extrusion hole 50 may be a hole having a polygonal cross section in addition to a hole having a circular cross section, or may be a screw hole. 4C is a cross-sectional view taken along the line CC ′ of FIG. A holder-side positioning surface 60 is provided inside the chip receiving hole 35, and the cutting edge 2 </ b> B of the chip 1 is moved in the longitudinal direction of the chip 1 by contacting the positioning surface 15 </ b> L <b> 1 or 15 </ b> L <b> 2 of the chip 1 inserted into the chip receiving hole 35. Positioned in direction Y.

  FIG. 5A is a perspective view showing the vicinity of the tip of a cutting tool set composed of a combination of the chip 1 and the chip holder 25 according to the third embodiment of the present invention. The chip 1 is inserted into the chip receiving hole 35 of the chip holder 25 and fixed and tightened by the tightening screw 70 in a state where the lower part 2C of the blade edge 2B is supported vertically upward (relative scoop direction H) by the lower jaw part 40. The chip holder 25 is fixed to a tool post (not shown) of a device that performs thread cutting, and cutting is possible. When the chip 1 is damaged or worn, it is replaced.

  FIG. 5B shows a sectional view of the cutting tool set. The chip 1 is positioned in the longitudinal direction L of the chip 1 by the contact between the positioning surface 15L1 of the chip 1 and the holder-side positioning surface 60 of the chip holder 25. The chip 1 is fixed by the bolt hole 30 and the fastening screw 70. In FIG. 5B, the front clearance angle A of the cutting edge 2B of the tip 1 and the clearance angle of the ridge line 40C of the lower jaw portion 40 at the tip of the tip holder 25 are equal, but may be different. However, in order to prevent chattering of the cutting edge, it is desirable that the lower part 2C of the cutting edge 2B of the tip 1 is supported vertically upward by a lower jaw part 40 protruding in a V shape like the lower part 2C. The lateral clearance angle at the tip of the chip holder 25 is preferably the same as the lateral clearance angle of the chip 1 but may be different.

  The body of the chip holder 25 is provided with an extrusion hole 50 in the direction parallel to the axis L of the receiving hole and facing the cutting edge of the cutting chip. However, it is not always necessary to be parallel, and it is sufficient if the chip can be pushed out.

  Next, the operation of taking out the chip 1 from the chip holder 25 in the above-described third embodiment will be described.

  FIG. 6 is an explanatory diagram for explaining a series of flows when the chip 1 is pushed out from the chip holder 25 and taken out. In the state where the chip 1 is housed in the chip housing hole 35 of the chip holder 25 as shown in FIG. 6A, the tightening screw 70 is loosened, and then the push bar 80 is inserted from the push hole 50. One end of the drum is hit with a hammer 75. Then, the chip 1 is pushed out in the direction of the arrow in FIG. 6B, and the chip 1 is taken out from the chip housing hole 35 as shown in FIG.

  FIG. 7 illustrates a female thread machining tip holder (bite holder) 87 according to a fourth embodiment of the present invention. This chip holder 87 is used when machining the chip 1 with an internal thread. FIG. 7A shows a side view of the chip holder 87. The end of the chip holder 87 is provided with a chip receiving hole 85 in a direction orthogonal to the longitudinal direction L of the main body of the chip holder 87 so as to be continuous with the lower portion of the chip receiving hole 85 and the main body of the chip holder 87. A lower jaw 90 is provided so as to protrude outward in the width direction from the side wall in the longitudinal direction L.

  FIG. 7B is an enlarged view of a cross section orthogonal to the axial direction (the width direction W of the chip holder 87) of the chip accommodation hole 85 for accommodating the chip. The chip receiving hole 85 is parallel to the axial direction W of the chip receiving hole 85 on the inner peripheral surface located on both sides of the virtual width direction X (which coincides with the longitudinal direction L of the main body) of the chip accommodated therein. A partial cylindrical region 92A having a virtual central axis C is formed. Further, a pair of inclined surfaces 95 extending in a direction parallel to the axial direction W of the chip receiving hole 85 is formed on the inner peripheral surface located at least one of both sides in the relative scooping direction H in the chip receiving hole 85. The pair of inclined surfaces 95 have a radius larger than that of the partial arc locus 92B on the extension line of the partial cylindrical region 42A in a cross section orthogonal to the virtual central axis C of the partial cylindrical region 92A formed on the inner periphery of the chip receiving hole 85. It is formed inside the direction. The inclined surface 95 of the female screw machining tip holder 87 is formed symmetrically with respect to the virtual central axis C of the chip receiving hole 85, and the center of curvature of the pair of partial cylindrical regions 92A coincides with this virtual central axis C. Further, the female thread machining tip holder 87 according to the fourth embodiment has a bolt hole 100 penetrating into the chip receiving hole 85 on the outer peripheral surface of the shank portion 88 facing the inclined surface 95, and the chip 1 is tightened with a bolt. Fix it.

  FIG. 7C is a cross-sectional view of a surface orthogonal to the tip holder main body longitudinal direction L at the tip of the female screw machining tip holder 87. Although the outer peripheral contour of the cross section in the direction perpendicular to the axis of the female screw machining tip holder 87 is substantially circular, the lower jaw portion 90 is formed to protrude outward in the width direction W (radial direction) with respect to the outer peripheral surface. The lower jaw portion 90 has a structure that supports the lower portion 2C of the cutting edge 2B of the tip 1 protruding from the outer peripheral surface vertically upward (relative scooping direction H upward). The lower jaw 90 is provided on the lower extension of the chip receiving hole 85. As will be described later, the chip 1 is accommodated in the chip accommodation hole 85, the positioning surface 15L1 of the chip 1 is brought into contact with the holder-side positioning surface 105 in the chip accommodation hole 85, and the positioning of the chip 1 in the longitudinal direction is accurate. Well done.

  FIG. 8A is a perspective view showing the vicinity of the tip of a cutting tool set in which a chip 1 is inserted into a female thread machining chip holder 87 according to a fifth embodiment of the present invention. A tip accommodating hole 85 is provided at the tip of the female screw machining tip holder 87, and the tip 1 is inserted therein. The lower part 2C of the cutting edge 2B of the chip 1 is supported vertically upward by a lower jaw part 90 provided on the outer peripheral surface of the female thread machining chip holder 87.

  As shown in FIG. 8B, the positioning surface 15L1 of the chip 1 is brought into contact with the holder-side positioning surface 105 in the chip receiving hole 85, so that the position of the cutting edge of the chip 1 in the protruding direction is accurately determined. Even during processing, positional deviation is unlikely to occur in the same protruding direction. That is, the holder-side positioning surface 105 can prevent the chip 1 from being displaced due to the back component force of the cutting resistance. Further, the inclined surface 4 of the chip 1 comes into contact with the inclined surface 95 of the chip holder 87 by the tightening screw 110, and the position of the cutting edge in the width direction is accurately determined. Further, since the lower portion 2C of the blade edge 2B is supported by the lower jaw portion 90, chatter and displacement can be suppressed to a minimum.

  FIG. 9 is an explanatory view for explaining a series of flows for taking out the chip 1 from the female thread machining chip holder 87.

  In a state where the chip 1 is housed in the chip housing hole 85 of the female thread machining chip holder 87 as shown in FIG. 9A, the tightening of the tightening screw 110 is loosened, and then the cutting is performed through the chip housing hole 85. The flank under the blades 2L1 and 2L2 on the side not facing (the side opposite to the lower jaw 90) is pushed toward the lower jaw 90 side. As a result, the chip 1 is pushed out in the direction of the arrow in FIG. 9B, and the chip 1 is taken out from the chip accommodation hole 85 as shown in FIG. In this embodiment, the female screw machining chip holder 87 is not provided with a dedicated extrusion hole for the chip 1, but a small-diameter dedicated extrusion hole is provided without penetrating the chip receiving hole 85 to provide a male screw machining chip holder. As in FIG. 6 in FIG. 25, the tip 1 may be pushed out using the push-out rod 80. In this case, the problem that chips enter from an opening that is not on the cutting side of the through hole of the chip accommodation hole 85 is solved.

  Next, as one of the fastening structures processed by the cutting tip, tip holder, and bite set according to the first to fifth embodiments, a so-called male screw body such as a bolt and a so-called female screw body such as a nut are used. Let me introduce.

  With respect to the fastening structure using this screw body, two types of spiral grooves (for example, a right male screw portion and a left male screw portion) having different lead angles and / or lead directions are formed on one male screw body, and the two types of spirals are formed. Some double threaded bodies (for example, a right female threaded body and a left female threaded body) are separately screwed into the groove, like a double nut. If the relative rotation of the two types of female screw bodies is suppressed by some engagement means, mechanical interference with the male screw is caused by the axial interference action or the axial separation action caused by different lead angles and / or lead directions. It can provide a locking effect.

  FIG. 10 (A) shows a double screw body in which two types of spiral grooves (a right male screw portion and a left male screw portion) having different lead directions are formed on one male screw body.

  The male screw body 140 is provided with a male screw portion 153 in which a male screw spiral structure is formed from the base side toward the shaft end. In this example, a first male screw spiral structure 154 serving as a right screw configured to be able to be screwed into a female thread-like spiral strip serving as a corresponding right screw is connected to the male screw portion 153, and a female screw-shaped serving as a corresponding left screw is provided. Two types of male screw spiral structures, the second male screw spiral structure 155 serving as a left-hand thread that can be screwed into the spiral strip, are formed on the same region. As shown in FIG. 10B, the male screw portion 153 has a substantially crescent-shaped thread 153a extending in the circumferential direction in the surface direction perpendicular to the axis (screw shaft) C, on one side of the male screw portion 153 ( They are provided alternately on the left side of the figure and the other side (right side of the figure). By configuring the screw thread 153a in this way, two types of spiral grooves, a spiral structure that turns clockwise and a spiral structure that turns counterclockwise, can be formed between the threads 53a.

  By doing so, two types of male screw spiral structures, the first male screw spiral structure 154 and the second male screw spiral structure 155, are formed in the male screw body 140. Therefore, the male screw body 140 can be screwed with any of the right screw and the left screw.

  In order to realize a fastening structure without loosening with a practical strength using such a double spiral structure (both screw bodies), Patent No. 4666313, which is the result of earnest research by the present inventor, etc. The special thread described in which the cross section perpendicular to the axis is substantially elliptical is effective (see FIG. 10B).

  The reference line extending in the tip body longitudinal direction Y when the blade portions 2L1, 2L2 of the cutting tip 1 according to the first embodiment of the present invention are viewed from the relative rake direction Z in FIG. The two main cutting blades 2D1 and 2D2 are provided symmetrically with respect to the cutting edge, that is, when two spiral strips having different lead directions are formed, only the feed direction is reversed to cut the thread. Preferred to make possible. Specifically, this shape enables finishing with radial infeed. However, since the infeed method is not limited to radial infeed, the angles of the two main cutting blades do not necessarily have to be the same.

  The embodiment of the cutting tip and the tip holder according to the present invention has been described above, but the present invention is not limited to the described embodiment, and various modifications can be made within the scope described in each claim. Is possible. For example, in FIG. 4B and the like, the chip receiving hole 35 is expressed as being provided in a direction parallel to the longitudinal direction L of the chip holder 25 main body with respect to the main body of the chip holder 25, but is inclined in the vertical direction. It may be. Although the chip receiving hole 85 of the female screw machining tip holder 87 is expressed in FIG. 7A so as to be provided in a direction orthogonal to the longitudinal direction L of the female screw machining chip holder 87, it is not limited to this.

  Next, the angle of the cutting edge 2B of the tip 1 applied when cutting the screw body will be described. Since the angle of the blade edge 2B is determined by the thread angle of the screw body, the thread angle of the thread body will be described here.

<Male threaded body and female threaded body>
As shown in FIGS. 11 and 12, a fastening structure 1001 of a male screw body 1010 and a female screw body 1100 to be processed is configured by screwing the female screw body 1100 into the male screw body 1010.

  As shown in FIGS. 14 and 15, the male screw body 1010 is provided with a male screw portion 1013 in which a male screw spiral groove is formed from the base side of the shaft portion 1012 toward the shaft end. In the present embodiment, the male screw portion 1013 has a first spiral groove 1014 serving as a right screw configured to be able to be screwed with a female screw-shaped spiral strip serving as a corresponding right screw, and a female screw-shaped serving as a corresponding left screw. Two types of male screw spiral grooves, which are second spiral grooves 1015 serving as left-hand threads that can be screwed into the spiral strip, are formed on the same region in the axial direction of the male screw body 1010. In addition to the overlapping portion, a single spiral groove region formed by forming a spiral groove in one direction may be provided.

  The first spiral groove 1014 can be screwed with a female thread-like spiral strip that is a right-hand thread of the female screw body 1100 corresponding thereto, and the second spiral groove 1015 is a female screw body 1100 corresponding thereto (this is the above-mentioned It can be screwed with a female thread-like spiral strip as a left-hand thread (including a case of a separate body from a female thread body having a right thread).

  As shown in FIGS. 14 (C) and 15 (C), the male screw portion 1013 has a substantially crescent-shaped thread extending in the circumferential direction in the surface direction perpendicular to the axis (screw shaft) C. Mountains G are alternately provided on one side (left side in the figure) and the other side (right side in the figure) of the male screw portion 1013 in the diameter direction. That is, the ridge line of the thread G extends perpendicular to the axis, and the height of the thread G changes so that the center in the circumferential direction becomes higher and both ends in the circumferential direction gradually become lower. By configuring the thread G in this way, a virtual spiral groove structure that turns clockwise (see arrow 1014 in FIG. 14A) and a virtual spiral groove structure that turns counterclockwise (FIG. 14 ( Two types of spiral grooves (see arrow 15 in A)) can be formed between the threads G.

  In this embodiment, by doing in this way, two types of male screw spiral grooves of the first spiral groove 1014 and the second spiral groove 1015 are superimposed on the male screw portion 1013. Therefore, the male screw portion 1013 can be screwed with any of the female screw bodies of the right screw and the left screw. For details of the male screw portion 1013 in which two types of male screw spiral grooves are formed, refer to Japanese Patent No. 4666313 related to the inventor of the present application.

  As shown in FIG. 13A, the female screw body 1100 includes a cylindrical member 1106. The cylindrical member 1106 has a so-called hexagonal nut shape and has a through-hole portion 1106a at the center. Of course, the general shape of the female screw body 1100 is not limited to the hexagonal nut shape, and can be arbitrarily set as appropriate, such as a cylindrical shape, a shape having a knurled surface, a square shape, and a star shape. A first female thread spiral 1114 as a right-hand thread is formed in the through-hole portion 1106a. That is, the first female screw spiral strip 1114 of the cylindrical member 1106 is screwed into the first spiral groove 1014 in the male screw portion 1013 of the male screw body 1010.

  As shown in FIG. 13B, as the female screw body 1101, a second female screw spiral strip 1115 as a left screw may be formed in the through hole portion 1106a. In this case, the second female screw spiral strip 1115 is screwed into the second spiral groove 1015 in the male screw portion 13 of the male screw body 1010.

  Next, with reference to FIG. 16 (A), the shape at the time of seeing the cross section along the axial direction of the thread G formed in the external thread part 1013 in the external thread body 1010 in an axial orthogonal direction is demonstrated.

  In addition, the shape of the thread P of the first female thread spiral 1114 of the female thread body 1100 and / or the second female thread spiral thread 1115 of the female thread body 1101 shown in FIG. 16B is the shape of the thread G of the male thread body 1010. Therefore, the detailed description is omitted here.

  Furthermore, the nominal diameter of the male screw body 1010 of the present embodiment will be referred to with the initial letter N. For example, in the case of the N16 male threaded body 1010, it means that the diameter F at the apex Gt of the thread G is 16 mm, and in the case of the N16 female threaded body 1100, the diameter of the thread valley is 16 mm. means.

  The thread angle T of the thread G (the thread angle means an angle formed by a pair of slopes extending from the top of the thread G toward the valley) is set in a range of 61 ° to 75 °, More preferably, it is set in a range of 65 ° to 73 °, more preferably 67 ° to 73 °, and more specifically 70 °. Further, the root diameter D of the thread G (that is, the outer diameter when the thread G is omitted in the shaft portion 1012 of the male thread body 1010) is set to 13.5 mm or more and 14.3 mm or less in the case of N16. It is preferable. The valley diameter D in the case of N16 is preferably set to 13.5 mm or more and 14.3 mm or less. The valley diameter D in the case of N24 is preferably set to 19.6 mm or more and 20.5 mm or less. The valley diameter D in the case of N30 is preferably set to 25.8 mm or more and 26.7 mm or less. The valley diameter referred to here is not the effective diameter as used in the conventional metric screw, but corresponds to the diameter of the valley bottom portion.

  Accordingly, as shown in FIG. 16 (B), also for the female threaded body 1100, the thread angle Q of the thread P is set in the range of 61 ° to 75 °, more preferably 65 ° to 73 °. More preferably, it is set to 67 ° or more and 73 ° or less, and more specifically, 70 °. In addition, in the case of N16, the peak diameter E of the apex Pt of the thread P is preferably set to 13.5 mm or more and 14.3 mm or less. The peak diameter E in the case of N16 is preferably set to 13.5 mm or more and 14.3 mm or less. The peak diameter E in the case of N24 is preferably set to 19.6 mm or more and 20.5 mm or less. The peak diameter E in the case of N30 is preferably set to 25.8 mm or more and 26.7 mm or less. Of course, it goes without saying that the setting of the thread diameter of the female screw needs to be set to be equal to or greater than the valley diameter of the male screw body.

<Design method and design basis>
Next, the design method and design basis of the male screw body 1010 and the female screw body 1100 will be described below. In addition, the example at the time of designing the external thread body 10 of the nominal diameter N16 is introduced here.

<Preparation of series of male screw body 10 and female screw body 100>
First, regarding the male screw body 10 having the nominal diameter N16, as shown in FIG. 17A, a plurality of different valley diameters D1, D2,..., Dn and a plurality of different mountain angles T1, T2,. .., A plurality of verification external thread bodies 10 (Tn, Dn) are prepared so as to fill a part or all of the matrix conditions composed of Tn.

  Further, the same number of verification female screw bodies 1100 that can be screwed to the plurality of verification male screw bodies 1010 (Tn, Dn) are prepared. That is, as shown in FIG. 17B, a matrix composed of a plurality of different crest diameters E1, E2,..., En and a plurality of crest angles Q1, Q2,. A plurality of verification internal thread bodies 1100 (Qn, En) are prepared so as to fill all or part of the conditions. Specifically, the crest diameter En of the verification female thread body 1100 (Qn, En) substantially matches the valley diameter Dn of the verification male thread body 1010 (Tn, Dn), and the crest angle Qn is equal to the verification male thread body 1010. This substantially coincides with the peak angle Tn of (Tn, Dn). As a result, the verification male screw body 1010 (Tn, Dn) and the verification female screw body 1100 (Qn, En) existing at the same position on the matrix in FIG. 17A and FIG. Many sets are prepared.

  Note that the axial length W of the verification female screw body 1100 (Qn, En) (this is also referred to as the axial length W, see FIG. 11) is the same for all test bodies in the fastening strength test at the nominal diameter N16. In addition, a predetermined ratio γ (0 <γ <1) specific to the material with respect to the nominal diameter N16 is set. That is, in the case of N16, the axial length W of the verification female screw body 100 (Qn, En) is set to 16 mm × γ. Of course, the value of W is calculated by multiplying a predetermined ratio γ that is a material specific value for each nominal diameter.

As shown in FIG. 18, the axially applied length W is approximately the tensile strength H that the axially perpendicular section 1012A of the shaft portion 1012 of the externally threaded body 1010 can withstand, and the thread of the externally threaded body 1010 at the axially applied length W. A value is selected such that the shear strength S of the peripheral surface J composed of the base surface GL of G (see FIG. 16A) is easily approximated. The tensile strength H is a value obtained by multiplying the cross-sectional area at the valley diameter Dn by the coefficient a1, and can be expressed by H = π × Dn ² × a1. The shear strength S is a value obtained by multiplying the cylindrical area corresponding to the length W in the axial direction at the valley diameter Dn by the coefficient a2, and can be expressed by S = π × Dn × W × a2.

  The coefficients a1 and a2 vary depending on the material of the base material, etc., but according to the study of the present inventor, in this embodiment, a general-purpose steel material such as S45C or SCM435 is selected as the base material, and W is the above-described value. It is known that the tensile strength H and shear strength S are very close to each other when set as described above. As a result, the fastening strength between the verification female screw body 1100 (Qn, En) and the verification male screw body 1010 (Tn, Dn) changes in the peak angle T and the valley diameter D. It becomes slightly larger or the tensile strength H side becomes slightly larger. Which is superior may be verified by a fastening strength test, and the boundary between the shear strength S-dominant state and the tensile strength H-dominant state can be found by experiment.

  Here, for convenience of explanation, the case where the matrix shown in FIG. 17 is used to vary the valley diameter D, the peak angle T, etc. is illustrated, but in actuality, for verification, all the places of the matrix are filled. It is not necessary to prepare the male screw body 1010 (Tn, Dn) and the verification female screw body 1100 (Qn, En), and it is not necessary to form a matrix. As will be described later, any mode may be used as long as the optimum value can be extracted by a combination of the verification external thread body and the verification internal thread body in which the valley diameter D and the peak angle T vary within a certain range.

<Boundary valley extraction process>
Next, a verification male screw body 1010 (Tn, Dn) and a verification female screw body 1100 (Qn, En) (hereinafter referred to as a verification bolt and nut set) are screwed together to perform a fastening strength test. In this fastening strength test, as shown in FIG. 18, the verification external thread body 1010 (Tn, Dn) and the verification internal thread body 1100 (Qn, En) are relative to each other in the axial direction (see arrow A). This means a tensile test in which the fastening state (screwed state) is forcibly released by moving, but is not particularly limited to this, and repeated male screw body 1100 (Tn, Dn) and female screw body 1100 (Qn, En) In addition to a fatigue test that causes relative separation, a so-called screw tightening test for verifying the torque, axial force, and rotation angle of the screw body may be used, and there is a correlation between these test results and the tensile test results. It has been confirmed that there is sex. A fastening strength test is performed on all the bolt and nut sets for verification, and the result is a shaft breaking form in which fastening is released by breaking at the shaft portion 1012 of the male screw body 1100, or the thread G is deformed or collapsed. It is judged whether it becomes the screw thread collapse form which fastening is cancelled | released by.

  A graph example of the determination result is shown in FIG. In this graph, the horizontal axis is set to the peak angle Tn, the vertical axis is set to the valley diameter Dn, the verification bolt and nut set in the shaft fracture configuration is indicated by ○, and the verification bolt and nut set in the screw thread collapse configuration is indicated by Δ. doing. As can be seen from this result, the graph is divided into a region X in which the thread breakage form occurs (screw breakage area X) and a region Y in which the shaft breakage form occurs (axial breakage area Y), and the boundary line K is clearly shown. can do. This boundary line K is defined as the change in the peak angle Tk and the boundary valley when the value of the maximum valley diameter that can cause the axial fracture form corresponding to a specific peak angle Tk is defined as the boundary valley diameter Dk. This means a correlation of changes in the diameter Dk.

  For example, the design philosophy of setting the crest angle T to 68 ° and the shank valley diameter D to 14.1 mm or more belongs to the thread collapse region X. This means that there is a high possibility that a thread crushing form will occur, and it can be considered that the design is such that the strength of the shaft portion is wasted. On the other hand, the design concept of setting the peak angle T to 68 ° and the valley diameter D of the shaft portion to 13.6 mm is easy to obtain a shaft fracture form at the time of fastening release, but the boundary valley diameter Dk is about 14.05 mm. Therefore, if it is within that range, it means that the valley diameter D of the shaft portion can be set larger and the tensile strength can be increased, which means that the design is inefficient.

  Paradoxically, from this boundary line K, the permissible range of the boundary mountain angle Tk that allows the male threaded body to be in an axially fractured form corresponding to the change in the boundary valley diameter Dk (this is referred to as the boundary mountain angle region Ts Can be determined).

<Axis fracture dominant thread angle selection process>
After the boundary valley diameter extraction step is completed, a peak angle (hereinafter referred to as an axial fracture dominant peak angle Tp) at which the boundary valley diameter Dk can be the maximum value is selected in the boundary line K. In the graph of FIG. 19, from the peak value of the boundary line K, the shaft fracture dominant mountain angle Tp is 70.5 °. Even if the shaft portion is made as thick as possible and the tensile strength is increased, the shaft breaking dominant mountain angle Tp has the highest mountain angle that is easy to lead to the shaft breaking mode, that is, the shear strength S on the mountain G side. It can be explained as an easy mountain angle.

<Thread angle determination process>
Finally, a design is performed by applying a crest angle that approximates the determined shaft fracture dominant crest angle Tp to the actual male screw body 1010 and / or the female screw body 1100 at the nominal diameter N16. For example, if the actual peak angle T is set to 70 °, the valley diameter D can be set large. As a specific valley diameter D, for example, about 14.25 mm is preferable.

  In addition, although the design method in the case of the nominal diameter N16 was demonstrated in FIG. 19, this invention is not limited to this, Other nominal diameters may be sufficient. For example, FIG. 20 shows a verification result graph for the nominal diameter N24, and FIG. 21 shows a verification result graph for the nominal diameter N30. What can be said in common in these graphs is that the axial break dominant peak angle Tp is in the range of 65 ° to 75 °, more preferably in the range of 67 ° to 73 °, and generally 70 °. Before and after. That is, in the case of the male screw body 1010 having the structure of the present embodiment, the thread angle of the thread is not 60 ° which is the conventional common sense, but a value larger than that is suitable, and the vicinity of 70 ° is the optimum value. I understand that.

  In the male screw body 1010 and the female screw body 1100 described above, the pair of the first spiral groove 1014 and the female screw spiral thread 1114 and the pair of the second spiral groove 1015 and the female screw spiral thread 1115 are in a reverse screw relationship (lead angle). However, the present invention is not limited to this. For example, as shown in FIG. 22, a first spiral groove 1014 and a female thread spiral 1114, and a second spiral groove 1015 and a female thread spiral 1115 having the same lead direction (L1, L2) and different lead angles may be adopted. it can. In this case, a spiral groove having a different lead angle is formed on the first spiral groove 1014 so that the lead is L1 (lead angle α1) and the lead is L2 (lead angle is α2). The second spiral groove 1015 is formed with the screw directions aligned. In this case, since the first thread G1 of the first spiral groove 1014 and the second thread G2 of the second spiral groove 1015 are not shared but are separated, at least one of the threads G1 and G2 is provided. The present invention may be applied and may be applied to both. Of course, the thread angle of the first thread G1 and the thread angle of the second thread G2 may be different from each other.

  In the above-described embodiment, the case of the male screw body 1010 having a double helix structure is illustrated. However, the present invention is not limited to this, and even in the male screw body 1010 having a single helix structure, the above-described design procedure is optimal. It is possible to theoretically and / or experimentally clarify the peak angle.

  As a result of the above, the angle I and the shape of the cutting edge 2B of the tip 1 may be set so that the thread can be machined. For example, the angle I substantially matches the “thread angle T” or It is preferable to set a smaller value. In the case where the chip 1 cuts with the cutting edge touching the base material, the angle J of the one-side cutting edge may be set to ½ of the angle I with respect to the direction perpendicular to the axis.

  The characteristics of the screw body and the ridge angle will be described as follows.

  (1) A shaft portion, a first spiral groove formed on a peripheral surface of the shaft portion and set in an appropriate lead angle and / or lead direction, and formed on a peripheral surface of the shaft portion, the lead angle and And / or a second spiral groove set in a different lead angle and / or lead direction with respect to the lead direction, wherein the first spiral groove and the second spiral groove are in the axial direction of the shaft portion. It has a thread portion formed in a strip shape by being superimposed on the same region, and the thread portion is viewed from the top of the thread when the section along the axial direction is viewed in the direction perpendicular to the axis. The male screw body is characterized in that a mountain angle formed by a pair of slopes extending toward the valley is set to 61 ° or more and 75 ° or less.

  (2) In relation to the male screw body, the crest angle is set to 73 ° or less.

  (3) In relation to the male screw body, the crest angle is set to 63 ° or more.

  (4) In relation to the male screw body, the crest angle is set in a range of 70 ° ± 3 °.

  (5) The female screw thread portion that has the female screw portion and that constitutes the female screw portion extends in a direction perpendicular to the axis in a cross section along the axial direction from the top of the screw thread of the female screw portion toward the valley. The female screw body is characterized in that a crest angle formed by a slope is set to 61 ° or more and 75 ° or less.

  (6) In relation to the female screw body, the male screw body according to any of the above may be screwed together.

  (7) The verification male screw body using a plurality of verification male screw bodies having different nominal angles and different crest angles and valley diameters, and a plurality of verification female screw bodies screwed into the verification male screw body In the case of performing a fastening strength test in which the female screw body for verification is screwed and relatively separated in the axial direction, the male broken body for verification is broken at the shaft portion to release the fastening state, and By causing the deformation of the screw thread of the verification external thread body to be deformed or sheared to cause both forms of the thread collapse form to be released, it can be near the boundary between the shaft fracture form and the thread collapse form. With respect to the valley diameter (hereinafter referred to as the boundary valley diameter), the boundary valley diameter is maximized based on the boundary valley diameter extraction step for extracting the degree of change due to the mountain angle variable and the degree of change in the boundary valley diameter. Can be a value The shaft fracture dominant mountain angle selecting step for selecting a constant mountain angle (hereinafter referred to as an axial fracture dominant mountain angle), and the actual male threaded body at the nominal diameter by using a mountain angle approximating the shaft fracture dominant mountain angle. And / or a thread angle determining step to be applied to the female threaded body.

  (8) In relation to the screw body design method, the boundary valley diameter extraction step includes a plurality of the verification external screw bodies in which the peak angle and the nominal diameter are constant and the valley diameters are different from each other, In the case of performing a fastening strength test in which a plurality of the internal thread bodies for verification that are screwed with the external thread body for verification are used, and the internal thread body for verification is screwed into the external thread body for verification and is relatively separated in the axial direction. Fracture both in the form of a shaft fracture in which the male screw body is broken at the shaft and the fastening is released, and in the form of a screw thread collapse in which the fastening is released when the screw thread of the verification male screw body is deformed or sheared And generating a specific boundary valley diameter extraction step that extracts a specific valley diameter (hereinafter referred to as a boundary valley diameter) that can be in the vicinity of the boundary between the shaft fracture form and the thread crushing form. Select the mountain angle, Based on the angle, the By repeating individual boundary valley 径抽 out process, characterized in that it and a step of extracting the degree of change of the boundary root diameter due to the mountain angle variable.

  (9) A male threaded body designed based on the above thread body designing method.

  (10) An internal thread body designed based on the above thread body design method.

  (11) A thread structure applied to a male thread body and / or a female thread body, wherein a thread angle formed by a pair of slopes extending from the top of the thread to the valley in the thread structure is 61 ° or more. It is a screw thread structure characterized by being set to 75 degrees or less.

DESCRIPTION OF SYMBOLS 1 Tip 2L1, 2L2 Blade part 3 Main-body part 4 Inclined surface 25 Tip holder 15L1, 15L2 Positioning surface 25 Tip holder 27 Shank part 30 Bolt hole 35 Tip accommodation hole 40 Lower jaw part 45 Inclined surface 50 Extrusion hole 60 Holder side positioning surface 70 Clamping screw 75 Hammer 80 Extruding rod 85 Tip receiving hole 87 Tip holder 90 Lower jaw part 95 Inclined surface 100 Bolt hole 105 Holder side positioning surface 110 Clamping screw 120 Tip holder 130 Throw away tip 140 Male screw body

Claims (28)

A cutting tip that performs cutting on a relatively moving external workpiece,
A columnar body,
A blade portion that is located at an end of the main body and includes a cutting edge;
A pair of inclined surfaces extending in the longitudinal direction of the main body are formed on a peripheral surface located on at least one of both outer sides of the blade in the relative scooping direction in the main body.
A cutting tip characterized by that.   A partial cylinder or a columnar region having a virtual central axis that is parallel to the longitudinal direction of the main body is formed on each of the peripheral surfaces located on both outer sides in the width direction of the rake face of the cutting edge in the main body. The cutting tip according to claim 1, characterized in that:   The pair of inclined surfaces are formed radially inward from an arc locus on an extension line of a partial arc that is a cross-section orthogonal to the longitudinal direction of the main body of the partial cylinder or columnar region. 2. The cutting tip according to 2.   The pair of inclined surfaces are formed symmetrically with respect to a reference line extending in the relative scooping direction from the tip of the blade edge when viewed from the longitudinal direction of the main body. The cutting tip according to any one of the above.   The cutting tip according to any one of claims 2 to 4, wherein the centers of curvature of at least the pair of partial cylinders or columnar regions coincide with each other. The blade portion is formed at one end in the longitudinal direction of the main body,
The cutting tip according to any one of claims 1 to 5, wherein the main body has a positioning surface that can be engaged with one of the external member and the longitudinal direction of the main body. The blade portions are respectively formed at both ends in the longitudinal direction of the main body,
The main body has a first positioning surface that can be engaged with one of the external member and the longitudinal direction of the main body, and a second positioning surface that can be engaged with the external member and the other of the longitudinal direction of the main body. The cutting tip according to any one of claims 1 to 5, wherein:   8. The tip of the blade edge in the blade portion has a symmetrical shape with respect to a reference line extending in the longitudinal direction of the main body when viewed from the relative scooping direction. The cutting tip according to 1.   The cutting tip according to any one of claims 1 to 8, wherein a front clearance angle of the cutting edge is 10 ° or more. A cutting tip that performs cutting on a relatively moving external workpiece,
A rake side abutting surface capable of abutting in the relative rake direction of the cutting edge with respect to the external member serving as a holder;
An anti-rake side contact surface that can contact the opposite side of the relative rake direction with respect to the external member serving as the holder;
A cutting tip comprising:   The cutting tip according to claim 10, further comprising a positioning surface that comes into contact with the external member in a protruding direction of the blade edge.   The rake-side contact surface and the anti-rake-side contact surface each include a partial cylinder or a columnar region having a virtual center axis that is parallel to the longitudinal direction of the main body. 11. The cutting tip according to 11.   The cutting tip according to claim 12, wherein both the rake side contact surface and the anti-rake side contact surface are provided by a single partial cylinder or columnar region.   The cutting tip according to any one of claims 1 to 13, wherein the cutting tip is obtained by processing a cylindrical material. A tip holder capable of holding a cutting tip at the tip of the holder body,
A tip holder having a receiving hole for receiving the cutting tip in a state in which a cutting edge is exposed at a tip portion of the holder main body.   The accommodation hole is formed with a pair of inclined surfaces extending in a direction parallel to the axial direction of the accommodation hole on an inner peripheral surface located on at least one of both sides in the width direction of the virtual rake face. Item 15. The chip holder according to Item 15.   16. A partial cylinder or a columnar region having a virtual central axis parallel to the axial direction of the receiving hole is formed on inner peripheral surfaces located on both sides in the width direction of the virtual rake face. Or the chip holder of Claim 16.   The pair of inclined surfaces are formed radially inward from a partial arc trajectory having a cross section perpendicular to the virtual central axis of the partial cylinder or columnar region formed on the inner periphery of the accommodation hole. The chip holder according to claim 17, wherein   The chip holder according to any one of claims 16 to 18, wherein the pair of inclined surfaces are formed symmetrically with respect to the virtual central axis of the accommodation hole when viewed from the axial direction. .   The chip holder according to any one of claims 17 to 19, wherein the centers of curvature of at least a pair of the partial cylinders or columnar regions coincide with each other.   21. The device according to any one of claims 16 to 20, further comprising: a bolt hole penetrating into the accommodation hole on the outer peripheral surface of the holder body facing the inclined surface, and the cutting tip is fastened and fixed by the bolt. The chip holder according to 1.   The hole for extruding the cutting tip toward the cutting edge of the cutting tip in a direction parallel to the axis of the receiving hole is provided in the holder body. The chip holder described.   The chip holder according to any one of claims 15 to 22, wherein the receiving hole has a receiving surface facing in a relative scooping direction.   The tip holder according to any one of claims 15 to 23, wherein the holder body has a positioning surface that can be engaged with one of the cutting tip and the longitudinal direction of the holder body.   A lower jaw portion for receiving the blade portion of the cutting tip is formed to be continuous with the lower surface of the housing hole and project from the tip portion of the holder body in the longitudinal direction of the cutting tip. The chip holder according to any one of claims 15 to 24.   The chip holder according to any one of claims 15 to 25, wherein an axial direction of the accommodation hole is perpendicular to a longitudinal direction of the holder main body.   The chip holder according to any one of claims 15 to 25, wherein an axial direction of the accommodation hole is parallel to a longitudinal direction of the holder body.   A cutting tool set in which the cutting tip according to any one of claims 1 to 14 is combined with the tip holder according to any one of claims 15 to 27.

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