JP2009034819A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool holder which is enhanced in mounting locational accuracy of a cutting edge, and can rigidly constrict the cutting edge, and to provide a cutting tool. <P>SOLUTION: The cutting tool is formed of an almost rodlike throwaway tip having a cutting edge at the front end, and the holder having an almost rodlike hole into which a rear end of the throwaway tip is inserted. The throwaway tip gets the side surface pressed by a fixing member arranged in the holder, and also the inclined surface inclined with respect to a direction that presses the fixing member. Then, by abutting the inclined surface on a fixing pin extending in a radial direction of the hole, the throwaway tip is fixed to the holder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting tool for mounting a throwaway tip having a substantially rod shape.

  Conventionally, as a cutting tool used for grooving or threading, a generally rod-shaped (bar-shaped) throw-away tip 42 having a cutting edge 41 at one or both ends is placed in a hole 44 of a holder 43 as shown in FIG. What has been inserted and fixed with bolts 45 or the like is known.

Further, in Patent Document 1, as a method for fixing a bar-shaped throw-away tip having cutting edges at both ends, a portion close to the cutting blade to be housed is brought into contact with a bolt fitted from the rear end side of the holder. A method of fixing is described.
JP 2001-71204 A

  However, in the conventional bar-shaped throw-away tip 42 shown in FIG. 12, since the protruding length of the bar is variable, the protruding length easily varies when the tip 42 is replaced, and the cutting edge 41 is displaced. In addition, there is a problem, and since the side surface of the bar is fastened and fixed with the bolt 45, the binding force in the rotation direction of the tip 42 is particularly weak, the tip 42 rotates during cutting, and the position of the cutting edge 41 shifts. There is a problem that 42 is easy to loosen.

  Further, in the cutting tool described in Japanese Patent Application Laid-Open No. 2001-71204, there is a possibility that the cutting blade close to the portion that comes into contact with the bolt may be lost due to vibration during mounting or during cutting. When using a blade, there is a problem in that the position accuracy of the cutting edge is shifted because the degree of chipping or wear of the cutting edge is different, and the binding force of the chip is insufficient.

  The present invention has been made in order to solve such a problem. The object of the present invention is to increase the accuracy of the mounting position of the cutting blade in the rotation axis direction and the tip direction, and to the rotation direction and the longitudinal direction of the chip. It is to provide a cutting tool that can be firmly restrained.

By adopting the following configuration, the present inventors can improve the mounting position accuracy of the cutting blade in the rotation axis direction and the tip direction even when the chip is replaced, and in particular, improve the restraining force in the longitudinal direction of the chip. And invented that stable processing is possible.
That is, the cutting tool according to an embodiment of the present invention, a substantially rod-shaped throwaway tip having a cutting edge at the tip, a holder having a substantially rod-shaped hole into which the rear end side of the throwaway tip is inserted, The throwaway tip has an inclined surface that is pressed against a side surface of the throwaway tip by a fixing member disposed in the holder and is inclined with respect to a pressing direction of the fixing member, The inclined surface is in contact with a fixing pin extending in the radial direction of the hole, and is fixed to the holder.

  According to the present invention, the tip can always be mounted at a predetermined position with respect to the rotation axis direction and the tip direction of the cutting edge, the cutting edge can be positioned easily and with high accuracy, and the restriction in the rotation direction of the tip can be achieved. By increasing the force, it is possible to prevent the displacement of the cutting edge and the loosening of the tip.

  1 (a) to 1 (c), FIG. 1 (a) and FIG. 1 (b) are side views of a cutting tool for inner diameter machining, which is an example in which a throw-away tip is mounted in a holder according to the first embodiment of the cutting tool of the present invention. FIG. 2 which is an arrow view of the cutting tool of a) as viewed from the A direction and FIG. 3 which is an arrow view of the cutting tool of FIG. 1A as viewed from the B direction will be described.

  According to FIG. 1, a cutting tool (hereinafter simply referred to as a tool) 1 has a substantially rod-shaped hole (hole) 3 formed at the tip of a holder 2, and a throw-away tip (hereinafter simply referred to as a simple tool) is formed in the substantially rod-shaped hole 3. It is abbreviated as a chip.) 5 is attached.

  According to FIG. 1 (a), the tip 5 has a substantially rod shape, has a cutting edge 6 on the outer side of the longitudinal tip, and the rear end has a partially different length from the distal end with respect to the longitudinal direction. The slanting restraint surface 9a (inclined surface 9a) has a shape, and this slanting restraint surface 9a (inclined surface 9a) is attached to the holder 2 (in FIG. 1A, a cylindrical fixing pin). 10), the cutting edge 6 can be positioned and mounted with high accuracy and the chip 5 can be firmly restrained even when the chip 5 is replaced. It is possible to prevent the tip 5 from rotating and the position of the cutting edge 6 from shifting or the tip 5 from loosening.

  Here, according to the present invention, the fixing member 11 fitted to both the holder 2 and the side surface of the chip 5 is characterized in that the side surface of the chip 5 is held while the chip 5 is pulled in the rear end direction. With this, the tip 5 can always be mounted at a specified position in the tip direction of the cutting edge, the cutting edge can be positioned easily and with high accuracy, and the restraining force in the longitudinal direction of the tip 5 is increased. Thus, the positional deviation of the cutting edge and the loosening of the tip 5 can be prevented.

  Further, in the first embodiment of the present invention, as shown in FIG. 1, the fixing member 11 is screwed into the presser fitting 12 fixed in contact with the side surface of the chip 5, and the presser fitting 12 and the holder 2. And a screw member 13 that fits both of them. According to this embodiment, the presser fitting 12 is pulled into the rear end side by screwing the screw member 13 into the presser fitting 12, and the tip 5 is moved by the movement of the presser fitting 12. It is configured to be drawn to the rear end side of the substantially rod-shaped hole 3 of the holder 2 so as to be dragged by

  Further, according to the fixing member 11 of FIG. 1, the presser fitting 12 is inclined so as to approach the tip 5 side from the front end to the rear end side of the holder 2, so that the presser fitting is tightened as the screw member 13 is tightened. Since 12 also tilts in the direction of restraining the side surface of the chip 5, the fixing member 11 can reliably contact the fixed position of the rear end while restraining the side surface of the chip 5.

  In the configuration of the first embodiment described above, as shown in FIG. 2, in particular, the retaining surface 14 is provided on the side surface of the chip 5, and the retaining surface 14 and one surface of the presser fitting 12 are in contact with each other. Although the shape is fixed, instead of this configuration, as shown in FIG. 4, the side surface shape of the chip 5 has a circular cross section, and a plurality of surfaces of the presser fitting 15 are in contact with and fixed to the side surface of the chip 5. Even if it is a thing, the chip | tip 5 can be restrained firmly.

  As shown in FIG. 1B, the rear end surface of the chip 5 has a protruding curved surface 9b whose length from the front end is partially different from the longitudinal direction, and the locking portion of the holder 2 is It has an oblique locking surface (an oblique locking surface provided on the rear end side of the substantially rod-shaped hole) 19 inclined obliquely with respect to the longitudinal direction of the substantially rod-shaped hole, and the rear end surface of the chip 5 is an oblique locking surface. Even with the configuration in contact with and fixed to 19, the chip 5 can be fixed with high accuracy and high restraining force.

  The protruding curved surface 9b has a convex curved shape when viewed from the side of the holder as shown in FIG. 1 (b), and has a rectangular shape when viewed from the top of the holder (viewed from the arrow B in FIG. 1 (b)). It is desirable that the protruding curved surface 9b and the oblique locking surface 19 are in line contact with each other in order to obtain a strong restraining force.

  Furthermore, as shown in FIG. 1C, the rear end surface of the chip 5 and the engaging portion of the holder 2 may be in surface contact with each other in a normal vertical cross-sectional shape.

  On the other hand, in FIG. 5 showing the second embodiment of the present invention, the fixing member 16 includes an eccentric pin 17, the outer periphery of the eccentric pin 17 is in contact with the side surface of the chip 5, and the eccentric pin 17. By tightening, the eccentric pin 17 rotates and the tip 5 is pulled to the rear end side. With this configuration, a strong restraining force can be obtained with a simple configuration. In this case, by further fixing the eccentric pin 17 with the bolt 18, the eccentric pin 17 is loosened and the force for pulling the tip 5 to the rear end side is not reduced, and the force for pulling the rear end side is maintained even during cutting. be able to.

    Incidentally, in this embodiment (FIG. 5), the tip 5 can be pulled to the rear end side by tightening the eccentric pin 17 with a left-hand screw.

  Further, as a specific third form of the fixing member 20, as shown in FIGS. 6 to 8, the fixing member 20 includes a collet chuck 21, and in particular, the collet chuck 21 is fitted in the holder 2. And a lock nut 23 having an inner wall surface on the outer periphery of the collet 22 and an outer wall surface screwed on the inner periphery of the holder front end outer ring portion 25, respectively. When the lock nut 23 is pulled to the rear end side of the holder 2 and the throw-away tip 5 is pressed against the locking portion (the cylindrical fixing pin 10 in FIGS. 6, 7 and 8), the positional accuracy of the cutting blade 6 is increased. In addition, it is desirable in that it can obtain a strong binding force.

  6 to 8, a holder tip intermediate portion (hereinafter abbreviated as a holder tip intermediate portion) 28 other than the portion where the lock nut 23 is fitted between the holder tip outer ring portion 25 and the collet 22; A bearing 26 is incorporated in a boundary portion with the tip outer ring portion 25. This prevents the holder tip intermediate portion 28 and the holder tip outer ring portion 25 from coming off, and creates a clearance between the holder tip intermediate portion 28 and the holder tip outer ring portion 25 so that the holder tip outer ring portion 25 can be smoothly moved. It is possible to rotate, and wear of the sliding portions of the holder tip intermediate portion 28 and the holder tip outer ring portion 25 can be prevented. Further, a nut 27 formed integrally with the collet 22 is provided at the tip of the collet 22, and the collet 22 can be easily removed by turning the nut 27 when the collet 22 is removed. it can.

  On the other hand, according to the present invention, the fixing pin 10 and the fixing members 11, 16, and 20 of the holder 2 may be steel, but are made of cemented carbide, cermet, or ceramics in terms of wear resistance and plastic deformation resistance. It may be configured.

  In addition, it is desirable that the fixing pin 10 is formed in a columnar shape that allows the portion that abuts the chip 5 to be accurately aligned and can be easily processed, but the side surface is partially cut away in the longitudinal direction and the portion that abuts the chip 5 The shape may be a plane or a polygonal prism.

  Furthermore, since the abutting portion of the fixing pin 10 is likely to be worn or deformed, it is desirable to replace the constant so that it can be replaced. A plurality of fixing pins 10 may be provided. On the other hand, the tip 5 is made of cemented carbide or cermet.

  1, 5 and 7, the oblique restraining surface 9 a (inclined surface 9 a) of the chip 5 is formed obliquely with respect to the longitudinal direction of the rod-like body, and has high dimensional accuracy in manufacturing and can be manufactured. There is an advantage that it is easy. As shown in FIG. 1, the inclination angle θ of the oblique restraining surface 9 (the angle formed between the direction S1 perpendicular to the longitudinal direction of the chip and the direction S2 of the oblique restraining surface 9) is 30 to 60 °, particularly 40 to 50 °. It is desirable in terms of improving the restraining force of the chip 5, preventing the oblique restraining surface 9 from being lost, and facilitating manufacture.

  Further, in the present invention, the shape of the rear end surface 9 is not limited to the above configuration, and as shown in FIG. 9, (a) the length in the longitudinal direction becomes shorter stepwise, that is, the rear end surface 9 has a plurality of It is formed so that the dimension in the longitudinal direction of the chip 5 changes continuously or stepwise, such as a configuration comprising a surface, and (b) a configuration in which the length is continuously shortened so that the rear end surface 9 forms a curved surface. (C) Any configuration such as a configuration in which the concave portion 18 whose length in the longitudinal direction is shortened in the central portion in the cross-sectional direction, or a combination thereof, may be used. In terms of dimensional accuracy, ease of manufacture, and local stress concentration to prevent local wear and breakage, the shape of the rear end face 9 is a structure in which the length is shortened continuously or stepwise, especially oblique The structure formed in is the best.

  Further, as described above, as shown in FIG. 9 (d), the rear end surface of the chip 5 has a protruding curved surface 9b having a long length in the longitudinal direction, and the engaging portion of the holder 2 is formed of the substantially rod-shaped hole. It has a slanting locking surface 19 that is inclined with respect to the longitudinal direction, and may have a configuration in which the rear end surface of the chip 5 is fixed in contact with the slanting locking surface 19 with high accuracy and high restraining force. Thus, the chip 5 can be fixed. Furthermore, as shown in FIG. 9E, the rear end surface of the chip 5 and the engaging portion of the holder 2 may have a normal vertical cross-sectional shape.

  Further, according to FIG. 10, which is an enlarged view of the chip 5 of FIGS. 1 to 9, the chip 5 includes a holder restraining portion 30 fixed in the hole 3 of the holder 2 and a protruding base portion 31 protruding from the holder 2. The diameter r2 of the protruding base 31 is smaller than the diameter r1 of the holder restricting portion 30, but the present invention is not limited to this, and the diameter r1 of the holder restricting portion 30 and the protruding base 31 are not limited thereto. May have the same diameter r2.

  In addition, it is desirable that the ratio r2 / r1 is 0.15 to 1, particularly 0.3 to 0.8 in that a small-diameter inner diameter can be processed and a restraining force of the holder 2 can be improved.

  Furthermore, the ratio L2 / L of the length L2 of the protruding base 31 to the total length L of the chip 5 is 0.4 to 3, particularly 0.5 to 0.5 in that the chip 5 can be firmly restrained and the chip 5 is downsized. 2 is desirable.

  Further, the tip 5 can change the diameter and length of the protruding base 31 depending on the application, and the holder restraining portion 30 can be the chip 5 having the same diameter and length so that the size of the protruding base 31 is different. The same holder 2 can be used for attachment.

  As shown in FIG. 11A, which is a view of the tip 5 of FIG. 10 viewed from the A direction, the cutting edge 6 is slightly s = 0.1-1 from the side surface following the horizontal cutting edge 6b of the protruding base 31. The protrusion base 31 formed on the outer side in the cross-sectional direction at .0 mm is prevented from interfering with the work material. The tip of the cutting edge 6 may be a sharp edge but may be an R surface with R = 0.2 mm or less. Here, as a method of forming the cutting edge 6, after producing the rod-shaped protruding base 31, the rear end portion of the protruding base 31 from the cutting edge 6 may be polished, or may be prepared in advance. The rod-shaped body may be manufactured so that is larger than the rod-shaped protruding base 31.

  Further, a rake face 7 is formed on the upper surface of the cutting edge 6, and the rake face 7 has a concave curved surface so as to function as a breaker. On the other hand, a front cutting edge 6 a is formed on the tip surface side of the cutting edge 6, and a side cutting edge 6 b is formed on the side face side of the cutting edge 6. Further, in order to efficiently discharge chips on the outer peripheral side surface of the protruding base 31 on the side of the cutting edge 6, a cutout portion 8 is formed that is cut inward from a shape assuming that the cross section of the protruding base 31 is a circle. .

  Further, the protruding base 31 of the chip 5 is basically formed in a circular cross section, but improves chip dischargeability during inner diameter processing and prevents interference with the processed work material wall surface. For this purpose, as shown in FIG. 11B, which is a BB cross-sectional view of the chip 5 of FIG. 10, the protruding base 31 has an oblong shape, or a retaining surface obtained by cutting out a part of a circle or an ellipse. You may consist of the shape which has.

  Furthermore, the holder and the tool of the present invention are particularly suitable for machining an inner diameter with a minimum diameter of 4 mm or less, and high-precision and high-quality machining can be stably achieved even in such an inner diameter machining.

(A)-(c) is a side view which shows the 1st embodiment of the cutting tool of this invention. It is the arrow line view seen from the A direction of the cutting tool of FIG. It is the arrow line view seen from the B direction of the cutting tool of FIG. It is an arrow view seen from A direction of the cutting tool of FIG. 1, and is a figure which shows the modification of a holding fixture. It is a side view which shows the 2nd embodiment of the cutting tool of this invention. It is sectional drawing which shows the 3rd embodiment of the cutting tool of this invention. It is sectional drawing which looked at the cutting tool of FIG. 6 from the A direction. It is a schematic perspective view of the cutting tool of FIG. (A)-(e) is the schematic which shows the modification of a rear-end surface about the cutting tool of this invention. FIG. 2 is an enlarged view of the throw-away tip in FIG. 1. (A) is the arrow directional view which looked at the throw away tip of FIG. 10 from A direction, (b) is BB sectional drawing of FIG. It is the schematic which shows the state which mounted | wore the holder with the conventional bar-shaped throwaway tip.

Explanation of symbols

1 Cutting tool
2 Holder 3 About rod-shaped hole (hole)
5 Throw away tip (chip)
6 Cutting blade
6a Front cutting edge
6b Horizontal cutting edge 7 Rake face 8 Notch 9 Rear end face
9a Oblique restraint surface (inclined surface)
9b Protruding curved surface 10 Fixing pins 11, 16, 20 Fixing members 12, 15 Presser fitting 13 Screw member 14 Holding surface 17 Eccentric pin 18 Bolt 19 Oblique locking surface (oblique locking provided on the rear end side of the substantially rod-shaped hole) surface)
21 Collet chuck 22 Collet 23 Lock nut 25 Holder tip outer ring part 26 Bearing 27 Nut 28 Holder tip intermediate part 30 Holder restraint part 31 Projection base

Claims (6)

A substantially rod-shaped throw-away tip having a cutting edge at the tip;
A holder having a substantially rod-like hole into which the rear end side of the throw-away tip is inserted,
The throw-away tip has an inclined surface that is pressed against a side surface of the throw-away tip by a fixing member disposed in the holder and is inclined with respect to a pressing direction of the fixing member. A cutting tool fixed to the holder in contact with a fixing pin extending in a radial direction of the hole.   The cutting tool according to claim 1, wherein the inclined surface is provided on a rear end side with respect to the fixing member.   The cutting tool according to claim 1, wherein the inclined surface is provided such that a dimension in a longitudinal direction of the throwaway tip decreases as the fixing member moves in a direction in which the fixing member presses a side surface of the throwaway tip. .   The cutting tool according to claim 1, wherein the inclined surface is pressed against a side surface of the fixing pin.   The fixing member includes a presser fitting that contacts and fixes a side surface of the throw-away tip, and a screw member that is screwed into the presser fitting and the holder and fits both together. The cutting tool according to any one of claims 1 to 4. 6. The throw-away tip is fixed in a state in which a restraint surface is provided on a side surface of the throw-away tip and the restraint surface is in contact with one surface or a plurality of surfaces of the presser fitting. Cutting tools.

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