JP2004074323A - Holder for cutting tool and cutting tool using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holder for a cutting tool and the cutting tool which are strongly fixed while enhancing the accuracy of mounting position of a cutting edge. <P>SOLUTION: An approximately cylindrical hole 3 for inserting a throwaway tip 5 is arranged in a longitudinal direction at the tip of the holder 2 for the cutting tool, and the throwaway tip 5 is fixed by the holder 2 for the cutting tool in which a fixing member to fix the throwaway tip 5 with the fixing member abutted on the end of the throw away tip 5 is arranged at the end of the approximately cylindrical hole 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cutting tool holder for mounting a substantially rod-shaped throw-away tip, and in particular, a cutting tool holder capable of mounting a throw-away tip having a high cutting edge position accuracy and a high restraining force, and the like. And a cutting tool using the same.
[0002]
[Prior art]
Conventionally, as a cutting tool used for grooving processing and thread cutting processing, as shown in FIG. 9, a substantially bar-shaped indexable insert 21 having a cutting edge 22 at one or both ends is inserted into a hole 24 of a holder 23. Is fixed by tightening it with a bolt 23 or the like.
[0003]
Japanese Patent Application Laid-Open No. 2001-71204 discloses a method in which a bar-shaped indexable insert having cutting edges at both ends is fixed by contacting a stored cutting edge with a bolt fitted from the rear end side of a holder. A method of fixing is described.
[0004]
[Problems to be solved by the invention]
However, the conventional bar-shaped indexable insert shown in FIG. 9 has a problem that the projection length is easily varied when the tip 21 is replaced because the projection length of the bar is variable, and the cutting edge is displaced. Also, since the side surface of the bar is pressed and fixed with bolts 25, the restraining force in the rotating direction of the chip 21 is particularly weak, and the chip 21 rotates during cutting to shift the cutting edge position or the chip 21 becomes loose. There was a problem that it was easy.
[0005]
Further, in the cutting tool described in Japanese Patent Application Laid-Open No. 2001-71204, there is a possibility that the cutting edge that comes into contact with the bolt may be damaged by vibration during mounting or during cutting, and the opposite cutting edge is used. In this case, there is a problem that the positional accuracy of the cutting edge is deviated because the degree of chipping or wear of the cutting edge is different each time.
[0006]
The present invention has been made to solve such a problem, and an object of the present invention is to provide a cutting tool holder and a cutting tool using the same, which can enhance the mounting position accuracy of the cutting blade and can firmly restrain the cutting blade. It is in.
[0007]
[Means for Solving the Problems]
By adopting the following configuration, the present inventors can improve the mounting position accuracy of the cutting blade even at the time of chip replacement, and can particularly improve the restraining force in the rotation direction of the chip, thereby achieving stable processing. Invented to be possible.
[0008]
That is, the cutting tool holder of the present invention is provided with a throw-away tip at the tip thereof, and a substantially rod-shaped hole for inserting the throw-away tip is provided at the tip of the cutting tool holder in the longitudinal direction. A fixing member for fixing the throw-away tip while being in contact with the end of the tip is provided at the end of the substantially rod-shaped hole.
[0009]
Here, it is preferable that the fixing member is formed of a rod-shaped body, and that the rod is disposed so that a longitudinal direction thereof is oriented in a cross-sectional direction of the holder, and that the fixing member is formed of a replaceable member.
[0010]
A first slit groove communicating with the substantially rod-shaped hole in a longitudinal direction of the tip of the cutting tool holder; and a second slit communicating with an end of the first slit groove and orthogonal to the substantially rod-shaped hole. A groove is provided, and between the holders is screwed with a screw member so as to penetrate the first slit groove in the vicinity of the substantially rod-shaped hole, and the throw-away tip inserted into the substantially rod-shaped hole is swaged, Alternatively, a holding plate that also serves as a part of the wall surface of the substantially bar-shaped hole is provided at the tip of the holder for the cutting tool, and a screw member is used between the holders so as to penetrate the holder and the holding plate in the vicinity of the substantially bar-shaped hole. It is desirable that the throw-away tip is screwed into the substantially rod-shaped hole and caulked.
[0011]
Further, the cutting tool of the present invention includes a throw-away tip having a cut surface having a cutting edge at one end and a cut portion having a short portion in the longitudinal direction at the other end, in the substantially rod-shaped hole of the cutting tool holder. It is characterized in that the insertable insert is fixed and the indexable insert is fixed in a state where the fixing member attached to the cutting tool holder and the cut surface are in contact with each other.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a plan view of an example of a cutting tool holder according to the present invention, which is an example in which a throw-away tip is mounted in a holder. FIG. 2 and FIG. 3 showing the cutting tool of FIG. 1 viewed from the direction B.
[0013]
According to FIG. 1, a cutting tool (hereinafter simply abbreviated as a tool) 1 has a hole 3 formed at the tip of a cutting tool holder (hereinafter simply abbreviated as a holder) 2, and a throw-away tip is formed in the hole 3. (Hereinafter, simply referred to as chip.)
[0014]
According to FIG. 1, the tip 5 has a substantially bar shape, has a cutting edge 6 at one end in the longitudinal direction, and has a shape having a cut surface 9 having a portion whose length in the longitudinal direction is short at the other end. By fixing the cut surface 9 in contact with the cylindrical fixing member 10 attached to the holder 2, the cutting blade 6 can be accurately positioned and mounted even when the chip 5 is replaced, and the chip 5 can be mounted. Since the tip 5 can be firmly restrained, 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 being loosened during cutting.
[0015]
Here, according to the present invention, the fixing member 10 of the holder 2 may be made of steel, but may be made of cemented carbide, cermet or ceramic in terms of wear resistance and plastic deformation resistance. It is desirable that the fixing member 10 is formed in a columnar shape that can be accurately aligned with the portion that comes into contact with the chip 5 and that is easy to process. May have a plane shape or a polygonal column shape.
[0016]
Further, since the abutting portion of the fixing member 10 is liable to be worn or deformed, it is desirable that the fixed member 10 be replaceable and constant exchange is performed. Further, a plurality of fixing members 10 may be provided. On the other hand, the tip 5 is made of cemented carbide or cermet.
[0017]
According to FIG. 1, the cut surface 9 of the chip 5 is cut obliquely with respect to the longitudinal direction of the rod-shaped body, and has advantages of high dimensional accuracy in manufacturing and easy manufacturing. As shown in FIG. 6, the cut angle θ of the cut surface 9 (the angle formed between the virtual end surface perpendicular to the axial direction of the holder restraining portion 15 and the cut surface) is 30 to 60 °, particularly 40 to 50 °. This is desirable from the viewpoint of improving the binding force of the cut surface, preventing loss of the cut surface 9, and facilitating manufacture.
[0018]
Further, in the present invention, the shape of the cut surface is not limited to the above configuration. As shown in FIG. 4, (a) the configuration in which the length in the longitudinal direction is gradually reduced, and (b) the cut surface 9 The cut surface 9 may be cut so that the length of the cut surface 9 changes continuously or stepwise, such as a configuration in which the length is continuously reduced so as to form a curved surface. Any configuration, such as a configuration in which a concave portion 18 having a reduced length in the longitudinal direction is provided at the central portion, or a combination thereof, may be employed. In order to prevent abrasion and breakage, a configuration in which the length is reduced continuously or stepwise, particularly a structure cut obliquely, is best.
[0019]
Further, in FIGS. 1 to 3, a first slit groove 11 communicating with the hole 5 for fixing the chip 5 in the longitudinal direction is provided at the tip of the holder 2, and the end of the first slit groove 11 is shown in FIG. As shown in FIG. 3, it communicates with a second slit groove 14 arranged in a direction orthogonal to the substantially rod-shaped hole, and has a U-shape in which the groove 11 is open on the tip side of the second slit groove 14. ing. Then, a bolt 12 is screwed into the holder 2 so as to connect between the first slit grooves 11 of the holder 2 (a U-shaped opening), so that the wall surface of the hole 3 is formed in the holder restraining portion 15 of the chip 5. The side surface of the chip 5 is pressed and restrained by the holder 2.
[0020]
Note that the method of restraining the chip of the holder 2 is not limited to the method of FIGS. 1 to 3. For example, as shown in FIGS. 5 (a) and 5 (b), the pressing plate 13 serving as a part of the wall surface of the substantially rod-shaped hole 5 May be provided separately from the holder 2 and the holding plate 13 may be fixed to the holder 2 by bolting. FIGS. 5A and 5B are views showing a modified example of the cutting tool of FIG. 1 viewed from the direction A.
[0021]
According to FIG. 6, which is an enlarged view of the chip 5 in FIG. 1, the chip 5 includes a holder restraining portion 15 fixed in the hole 3 of the holder 2 and a projecting portion 16 projecting from the holder 2. Although the protrusion 16 is formed so that the diameter r ₂ of the protrusion 16 is smaller than the diameter r ₁ of the restraint 15, the present invention is not limited to this, and the diameter r ₁ of the holder restraint 15 and the protrusion r 16 diameter _{r 2} of the may be the same. The ratio of r ₂ / r ₁ is desirably 0.15 to ₁ , particularly 0.3 to 0.8, in that the inside diameter of a small diameter can be machined and the restraining force of the holder can be improved. Furthermore, in terms of being able to firmly restrain the chip 5 and reducing the size of the chip 5, the ratio L ₂ / L of the length L ₂ of the protruding portion 16 to the entire length L of the chip 5 is 0.4 to 3, especially 0.1 to 0.3. It is desirable to be 5 to 2. In addition, the diameter and the length of the protrusion 16 can be changed according to the use of the chip 5, and even if the holder 5 has the same diameter and the same length, the size of the protrusion 16 is different. It can be mounted using the same holder 2.
[0022]
As shown in FIG. 6 and FIG. 7A, which is a view of the chip 5 in FIG. The protrusion 16 is formed on the outside in the cross-sectional direction to about 1.0 mm to prevent the projection 16 from interfering with the work material. The tip of the cutting blade 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, a rod-shaped projection 16 may be manufactured, and then a portion of the projection 16 at a rear end of the cutting blade 6 may be polished or manufactured. The rod-shaped body may be manufactured such that is larger than the rod-shaped protrusion 16.
[0023]
A rake face 7 is formed on the upper surface of the cutting blade 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 6a is formed on the distal end face side of the cutting edge 6, and a horizontal cutting edge 6b is formed on the side surface side of the cutting edge 6, respectively. Further, a notch 8 is formed between the rake face 7 and the protruding portion 16 for efficiently discharging chips.
[0024]
Further, as shown in the chip 5 of FIG. 6, the protruding portion 16 of the chip 5 is basically formed in a circular cross section. As shown in FIG. 7B, which is a cross-sectional view taken along the line BB of the chip shown in FIG. May be formed by cutting out the shape.
[0025]
Furthermore, the holder restraining portion 15 has a circular cross section in terms of easiness of processing, shortening of a manufacturing process, improvement in mounting accuracy of the chip 5, and improvement in restraining force, that is, the holder restraining portion 15 is a round bar. desirable.
[0026]
According to the present invention, as shown in FIG. 8, in order to increase the binding force of the chip 5, a concave notch 20 is provided on the chip side surface, and the screw member 21 fixed to the holder 2 is provided in the notch 20. It is also possible to insert.
[0027]
Although the holder and the tool of the present invention can be used for turning, they are particularly suitable for the machining of very small diameters having a diameter of 4 mm or less, particularly 3 mm or less. It is possible to achieve high-quality processing having an accurate and smooth finished surface.
[0028]
【The invention's effect】
As described above in detail, according to the present invention, the fixing member is provided at the end of the substantially rod-shaped hole into which the chip of the holder is inserted, and the end of the chip is fixed by abutting the fixing member at the specified position. The cutting blade can be mounted, and the positioning of the cutting blade can be performed easily and with high precision. In addition, the restraining force in the rotating direction of the chip can be increased to prevent displacement of the cutting blade and loosening of the chip.
[0029]
Further, by making the cut surface oblique, a chip can be easily manufactured with high dimensional accuracy and without local stress concentration.
[0030]
Further, the holder and the tool of the present invention are particularly suitable for machining an extremely small diameter having a diameter of 4 mm or less, and can stably achieve high-precision and high-quality machining in such an extremely small inside diameter.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a cutting tool in which a throw-away tip is mounted on a cutting tool holder of the present invention.
FIG. 2 is a view of the cutting tool of FIG. 1 as viewed from a direction A.
FIG. 3 is a view of the cutting tool of FIG. 1 as viewed from a direction B.
FIG. 4 is a schematic view showing another embodiment of a cut section of the indexable insert attached to the cutting tool holder of the present invention.
FIG. 5 is a sectional view showing another embodiment of the cutting tool holder of the present invention.
FIG. 6 is an enlarged view of a main part of the throw-away tip of FIG. 1;
7 (a) is a view of the throw-away tip of FIG. 6 viewed from a direction A, and FIG. 7 (b) is a cross-sectional view of FIG. 6 along BB.
FIG. 8 is a plan view showing another embodiment of the indexable insert of the present invention.
FIG. 9 is a plan view showing a state where a conventional bar-shaped throw-away tip is mounted on a holder.
[Explanation of symbols]
1 cutting tool (tool)
2 Holder 3 Hole 5 Indexable insert (tip)
6 Cutting Edge 6a Front Cutting Edge 6b Horizontal Cutting Edge 7 Rake Surface 8 Notch 9 Cut Surface 10 Fixing Member 11 First Slit Groove 12 Bolt 13 Holding Plate 14 Second Slit Groove 15 Holder Restraining Part 16 Projecting Part 18 Recess 19 Notch 20 Screw member

Claims (6)

A cutting tool holder for mounting a throw away tip at a tip thereof, wherein a substantially rod-shaped hole for inserting the throw away tip is provided in a longitudinal direction on a tip side of the cutting tool holder, and abutted against an end of the throw away tip. A holder for a cutting tool, wherein a fixing member for fixing the throw-away tip in a state is provided at an end portion of the substantially rod-shaped hole. The fixing member is formed of a rod, and the rod is disposed so that a longitudinal direction of the rod faces a cross-sectional direction of the holder, and a side surface of the fixing member and an end of the throw-away tip are in contact with each other. The cutting tool holder according to claim 1. 3. The cutting tool holder according to claim 1, wherein the fixing member is made of a replaceable member. A first slit groove communicating with the substantially rod-shaped hole in the longitudinal direction of the tip of the cutting tool holder, and a second slit communicating with the end of the first slit groove and arranged in a direction orthogonal to the substantially rod-shaped hole. Is provided, and the holder is screwed with a screw member so as to penetrate the first slit groove in the vicinity of the substantially rod-shaped hole, and the throw-away tip inserted into the substantially rod-shaped hole is swaged. The cutting tool holder according to any one of claims 1 to 3, wherein: At the tip of the cutting tool holder, a holding plate also serving as a part of the wall surface of the substantially rod-shaped hole is provided, and a screw member is used to screw between the holder and the holding plate so as to penetrate the holder and the holding plate near the substantially rod-shaped hole. The cutting tool holder according to any one of claims 1 to 3, wherein the indexable insert inserted into the substantially rod-shaped hole is swaged together. A cutaway insert having a cutting surface having a cutting edge at one end and a portion having a short length in the longitudinal direction at the other end is inserted into the substantially bar-shaped hole of the cutting tool holder according to any one of claims 1 to 5. And a cutting tool, wherein the indexable insert is fixed in a state where a fixing member attached to the cutting tool holder is in contact with the cut surface.

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