JP2006007365A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool such as a grooving cutting tool capable of improving machining efficiency and working safety for machining a semicircular groove by transferring a semicircular shape of a cutting edge of a circular tip. <P>SOLUTION: In the cutting tool, a plurality of pointed ends 8 are provided at a chip disposing part of a breaker piece 5 arranged on a cutting face of the circular tip 3. The pointed ends 8 are (i) on lines radially extended from a reference point O placed near the center of the circular tip 3 in a plane view of the tool, (ii) inside a virtual semicircle S described around the reference point O, and placed on positions to be symmetric with reference to a center line C of the breaker piece 5. (iii) The size of the virtual semicircle S is approximately the same as that of the cutting edge 3a. An outer end of each pointed end 8 is on the virtual semicircle S. Each pointed end 8 is inclined at a predetermined angle and an inner end of each pointed end 8 is closer to the center of the virtual semicircle S than the outer end. (iv) Each pointed end 8 has a predetermined wedge angle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cutting tool such as a grooving tool or a cutting tool having a circular cutting edge tip.

  Among the commercially available cutting tools, there are PRGC R / L type, PRDCN type, RP02 R / L type (all are model numbers according to ISO standards). The former two are tools provided for general / copy cutting, and the latter are for copy cutting. These all use circular tips (round piece tips) as cutting edge tips.

  When a groove having a semicircular cross section is machined using a cutting tool having a circular tip, it is important to surely process the chips.

The processing of the chips is usually performed by any of the following methods (1) to (4).
(1) The breaker piece 5 is arranged on the rake face of the circular chip 3 attached to the holder 2, and the generated chip is made to collide with the breaker piece 5 to impart curl or distortion for cutting to the chip. (See FIG. 11).
(2) A chip provided with a breaker groove 3b along the cutting edge 3a is used, and the chip is distorted by the breaker groove of this chip (see FIG. 12).
(3) Using a chip in which a plurality of protrusions 3c are further provided in the breaker groove 3b, the chip is distorted by the breaker groove and the protrusion (see FIG. 13).
(4) A raised land portion 3d is provided on the upper surface of the chip, and distortion is imparted to the chips on the inclined side surface of the land portion (see FIG. 14).

  However, the above methods (1) to (4), which are known as general methods of chip disposal, cannot sufficiently cope with chips when processing a semicircular groove.

As shown in FIG. 15 (a), when performing the groove processing to transfer the semicircular shape of the chip to the workpiece W while moving the cutting tool 1 in one direction, the cutting as shown in FIG. 15 (c) is performed. Waste A is generated. Its chip A, as shown in FIG. 15 (b), the maximum thickness P ₂ becomes the width-direction center portion of the cutting edge 3a, gradually thinner thickness toward therefrom across the cutting edge of the semicircle, The minimum thickness P ₁ is obtained at both ends.

  As shown in FIG. 15 (c), the chip A having a changed thickness cannot be effectively processed by the measures (1) to (4), and is condensed and the direction of the semicircle is reversed. It is deformed into a shape and stretches long without being divided, making it difficult to discharge.

  It is necessary to stop the processing machine in order to process the chips that extend without breaking, and productivity is lowered. In addition, the chips that are not divided have sharp edges, and there is a danger in the removal work.

  The present invention provides a cutting tool capable of reliably cutting and processing chips even when machining a semicircular groove by transferring the semicircular shape of a cutting edge in order to improve machining efficiency and work safety. The issue is to provide.

In order to solve the above-described problems, in the present invention, in a cutting tool in which a circular chip is mounted on a holder and a breaker piece is provided on a rake face of the circular chip, the chip processing section of the breaker piece has the following (i ) To (iv) are provided with a plurality of tips, and a V-shaped valley is provided between adjacent tips.
(I) Each tip is on a line extending radially from a reference point placed near the center of the circular tip in a plan view of the tool.
(Ii) Each tip is inside a virtual semicircle drawn with the reference point as the center, and is in a position that is symmetrical with respect to the center line of the breaker piece.
(Iii) The virtual semicircle has a size substantially along the cutting edge of the circular chip, and there are outer ends of the tips on the virtual semicircle, and the tips of the tips are inclined at a predetermined angle, and the inner ends of the tips. Is closer to the center of the virtual semicircle than the outer end.
(Iv) Each point has a predetermined wedge angle.

  In this cutting tool, it is preferable that a circular tip is attached to the tip of the protruding portion provided in the holder, and a position adjusting mechanism for changing the fixing position of the breaker piece in the protruding direction of the protruding portion is added.

  In addition, it is preferable that at least the chip treatment portion of the breaker piece is formed of a material having a higher hardness than the base portion of the breaker piece. As a material at this time, for example, a combination of a cemented carbide and a steel material can be considered. The chip disposal part formed of cemented carbide or the like is fixed to the base by brazing or screwing. Note that the entire breaker piece may be formed of cemented carbide.

  In the cutting tool of the present invention, the breaker piece is provided with a plurality of tips, and the chips are made to collide with the tips to be processed. Chips that have collided with the tip end are cut vertically by the tip end and divided into a plurality of portions in the width direction (the number of divisions n at this time is the total number of the tip ends + 1). Therefore, the degree of the thickness change of each chip becomes small and the chip is easily deformed. The deformed chips are pressed against the valleys on both sides of the tip and deformed into a U-shape, and in this state, are subjected to further curling force, so that they are easily divided and processed well.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show a byte 1 to which the present invention is applied. The cutting tool 1 is provided with a projecting portion 2a projecting laterally at the front portion of the holder 2, and a circular chip 3 is mounted in a seat groove provided at the tip of the projecting portion 2a. The circular chip 3 is a positive chip whose side surface is inclined at an angle γ.

  The circular chip 3 is fastened with a clamp screw 4 (see FIG. 4) and fixed to the holder 2, and a breaker piece 5 is fixed on the circular chip 3 with a bolt 6. An adjusting mechanism 7 for adjusting the fixing position of the breaker piece 5 is provided behind the breaker piece 5.

The breaker piece 5 is provided with a plurality of tips 8 on the chip disposal part (front side). Here, the total number of the tips 8 is 3, and one of them is arranged on the center line C of the breaker piece 5 as shown in FIG. 5, and the other two are left and right from the center line C of the breaker piece 5. _The breaker pieces 5 are arranged symmetrically with respect to the center line C, respectively. θ ₁ is preferably set to about 30 ° to 45 ° in order to divide the chips into an average width when the total number of the tips 8 is 3.

Each tip 8 is on a line extending radially from a reference point O disposed near the center of the circular tip 3 in a plan view of the tool. Each tip 8 is inside a virtual semicircle S drawn around the reference point O. The virtual semicircle S has a size substantially along the cutting edge 3 a of the circular chip 3, and the outer end of each pointed tip 8 is on the virtual semicircle S. Further, each tip 8 is inclined at a predetermined angle θ ₂ (see FIG. 4), and the inner end of each tip is closer to the center of the virtual semicircle S than the outer end of the tip. Each tip 8 has a predetermined wedge angle θ ₃ (see FIG. 8).

If the inclination angle θ ₂ of the pointed tip 8 is too small, it becomes difficult for the chips to flow and the cutting resistance increases. If it is too large, the resistance given to the chips decreases and the processability for the chips decreases. It is preferable to set the angle to about 50 ° to 50 °. In addition, the wedge angle θ ₃ is preferably set to about 30 ° to 60 ° because the tip 8 is likely to be worn when it is too small, and the effect of tearing off chips is reduced when it is too large.

  A V-shaped valley 9 is provided between the adjacent tips 8. A trough 10 curved in a concave shape is also provided behind the tip 8 at both ends.

  If one of the tips 8 is arranged on the center line C of the breaker piece 5 as shown in the figure, the tip 8 on the center line can impart distortion to the thickest part of the chip during grooving, The number of the tips 8 may be an even number, and may be arranged symmetrically at a position deviating from the center line C of the breaker piece 5.

  When the breaker piece 5 is structured as shown in FIGS. 6 and 7, the durability is improved and the repair when it is worn becomes easy. The breaker piece 5 of FIG. 6 has a base portion 5a made of steel, and a chip treatment portion 5b made of cemented carbide, respectively, and provided with tip 8 and valleys 9 and 10 characterizing the present invention in the chip treatment portion 5b. The chip disposal part 5b is brazed and fixed to the base part 5a. Such a structure may be adopted when there is a margin in size and the chip disposal portion 5b can be fixed to the base portion 5a with the set screw 11 as shown in FIG. If it is a screwing system, the damaged chip disposal part 5b can be easily replaced. The breaker piece 5 can be entirely made of a cemented carbide or the like.

  Next, the adjusting mechanism 7 is provided for the purpose of adjusting the tip position of the breaker piece 5. The adjusting mechanism 7 employed here makes the adjustment screw 7a screwed into the holder 2 abut on the back surface of the breaker piece 5, and operates the adjustment screw 7a to move the breaker piece 5 in the piece longitudinal direction (the protruding direction of the protruding portion 2a). )). When the position of the breaker piece 5 is adjusted, the bolt 6 is loosened, and the breaker piece 5 is advanced and retracted within the range of accommodation by utilizing the flexibility provided between the bolt 6 and the breaker piece 5. It is not limited to.

  The optimum value of the distance Δw (see FIG. 4) from the cutting edge 3a to the tip 8 changes according to the cutting conditions of the cutting tool. A device provided with the adjusting mechanism 7 can cope with the fluctuation of the distance Δw. Further, when the tip 8 provided on the breaker piece 5 is worn, re-polishing and regenerating the tip 8 and the valleys 9 and 10 reduce economic loss. However, when the re-polishing is performed, the position of the tip 8 is retracted. . The variation of the distance Δw at this time can also be corrected to an optimum value if the adjusting mechanism 7 is provided.

  The illustrated cutting tool 1 is provided with a key 12 (see FIG. 4) on the lower surface of the breaker piece 5, and the key 12 is inserted into a key groove 13 (see FIG. 4) on the holder 2 side. The breaker piece 5 can be stably fixed with a single bolt 6.

  FIG. 9 and FIG. 10 show how the chips are divided by the exemplified cutting tool 1. As shown in FIG. 15 (a), the cutting tool A generated when the cutting tool 1 is fed in one direction to process a semicircular groove hits the three sharp tips 8 provided on the breaker piece 5 and is cut vertically. Therefore, it is divided into four so that it can be easily deformed.

  Next, the four-divided chips hit the valleys 9 and 10 and are deformed into a square shape under resistance. Further, it receives a curling force in the longitudinal direction, and is distorted in a complicated manner and processed well. Therefore, if this cutting tool 1 is used, it becomes possible to process the round groove efficiently, and dangerous chips are not generated, and the safety of work is improved.

Top view of a tool to which the present invention is applied Side view of the cutting tool of FIG. End view of the cutting tool in FIG. The expanded sectional view of the part along the XX line of FIG. The top view which expands and shows the breaker piece front-end | tip part of the cutting tool of FIG. The perspective view which looked at the breaker piece from the lower surface side The perspective view which shows some other examples of a breaker piece seeing from a lower surface side Sectional view showing one of the tips The perspective view which shows the chip processing state in an example bite The top view of the chip disposal status of the example tool A perspective view showing a conventional breaker piece Cross-sectional view of circular tip with breaker groove Plan view of circular chip with breaker groove and protrusion Cross section of circular chip with land (A) Perspective view showing an example of round groove processing by a cutting tool, (b) A diagram showing a cross-sectional shape of chips generated by feeding the cutting tool, (c) A perspective view showing a chip generation state in a conventional cutting tool

Explanation of symbols

1 Bite 2 Holder 2a Protruding part 3 Circular tip 3a Cutting edge 4 Clamp screw 5 Breaker piece 5a Base part 5b Chip treatment part 6 Bolt 7 Adjustment mechanism 7a Adjustment screw 8 Pointed end 9, 10 Valley 11 Set screw 12 Key 13 Keyway

Claims (4)

In a cutting tool in which a circular tip is mounted on a holder and a breaker piece is provided on the rake face of the circular tip, a plurality of sharp tips satisfying the following conditions (i) to (iv) are provided in a chip disposal portion of the breaker piece Furthermore, the cutting tool characterized by providing the V-shaped valley | valley between adjacent cusps.
(I) Each tip is on a line extending radially from a reference point placed near the center of the circular tip in a plan view of the tool.
(Ii) Each tip is inside a virtual semicircle drawn with the reference point as the center, and is in a position that is symmetrical with respect to the center line of the breaker piece.
(Iii) The virtual semicircle is sized substantially along the cutting edge of the circular chip, and the outer end of each tip is on the virtual semicircle, and each tip is inclined at a predetermined angle to be the inner end of each tip. Is closer to the center of the virtual semicircle than the outer end.
(Iv) Each point has a predetermined wedge angle.   The cutting tool according to claim 1, wherein the number of the tips is an odd number, and one of the tips is arranged on the center line of the breaker piece.   The cutting tool according to claim 1 or 2, further comprising a position adjusting mechanism that attaches the circular tip to a tip of a protruding portion provided in a holder and changes a fixing position of the breaker piece in a protruding direction of the protruding portion.   The cutting tool according to any one of claims 1 to 3, wherein at least a chip disposal portion of the breaker piece is formed of a material having a hardness higher than that of a base portion of the breaker piece.

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