JP6017918B2 - Inserts and cutting tools - Google Patents

Description

  The present invention relates to an insert having a cutting edge at the tip of a substantially rod-shaped shank, and a cutting tool for mounting the insert on a holder.

  2. Description of the Related Art Conventionally, as a cutting tool used for bore boring or grooving of an inner diameter, an approximately rod-shaped insert having a cutting edge portion is inserted into a hole of a holder and fixed by tightening with a bolt.

  For example, in Patent Document 1, a substantially rod-like insert having a cutting edge portion brazed with a blade made of a diamond sintered body or a cubic boron nitride (cBN) sintered body at the tip is inserted into the hole from the tip of the holder. A cutting tool is disclosed in which an insert is fixed with a screw member penetrating the holder, and the cutting tool is used to insert a part from the cutting edge portion of the insert to a part of the shank portion into the machining hole of the work material. A method of inserting and performing inner diameter processing or the like is known. Patent Document 2 discloses a cutting tool in which one of four apex angles is an obtuse V-shaped flat plate blade part brazed onto a base material made of cemented carbide, and an acute angle part with a small edge angle. Is the cutting edge.

Japanese Patent Laid-Open No. 10-128603 JP 2000-126906 A

  However, in the cutting tool brazed blade portion made of diamond sintered body and cBN sintered body of Patent Documents 1 and 2, because it often processes difficult-to-cut materials, because the heat generated by the cutting process is high, There was a problem that the temperature of the blade portion rose and crater wear was likely to proceed.

  The objective of this invention is providing the insert and cutting tool which can improve heat dissipation also in the internal diameter process etc. of a difficult-to-cut material.

The insert of the present invention is substantially rod-shaped, and includes a shank portion having a substantially circular shape when viewed from the tip, and a cutting edge portion provided at the tip of the shank portion,
The cutting blade portion includes a base portion and a blade portion brazed to the base portion, the blade portion includes a cutting blade including a front cutting blade and a side cutting blade, and a rake face,
The ratio (L _f / L _b ) between the length L _{b of the} base portion on the front cutting edge side and the length L _f of the front cutting edge of the blade portion is 0.4 to 1, and the front cutting The blade edge angle, which is the angle between the front cutting edge and the side cutting edge, and the ratio (L _f / L _s ) of the blade length L _f to the length L _s of the side cutting edge is 2 or less θ is 70 ~ 80 ° Tona is,
At the tip of the shank part, a rising part is provided behind the base part provided following the blade part of the cutting blade part, and a step is provided between the base part and the rising part.
Thus, the base portion has a lower height than the rising portion .

  Moreover, the cutting tool of this invention inserts the said insert in the elongate insertion hole provided in the front end side of the holder, and is being fixed.

According to the insert of the present invention and the cutting tool equipped with the insert, it is possible to efficiently spread the cutting heat generated by the inner diameter machining of difficult-to-cut materials and the like to the entire blade portion, thereby reducing the temperature rise of the blade portion. The progress of crater wear generated in the blade portion can be suppressed, and the cutting performance of the blade portion is maintained.

It is (a) top view, (b) side view, (c) tip view of one embodiment of the insert of the present invention. It is (a) top view, (b) side view, (c) tip view of another embodiment of the insert of the present invention. FIG. 2A is a top view of a cutting tool in which the insert shown in FIG. 1 is mounted on a holder, FIG.

  1 and 2 which are embodiments of the insert 1 of the present invention, and FIG. 3 which is an embodiment of the cutting tool 30 for inner diameter processing which is used by attaching it to the holder 20 will be described.

  In FIG. 1, the insert 1 is provided with a shank portion 2 having a substantially rod shape and having a substantially circular shape when viewed from the tip, and a cutting blade portion 3 following the tip of the shank portion 2. The cutting edge portion 3 includes a base portion 4 and a blade portion 5 brazed to the base portion 4, and the blade portion 5 includes a cutting edge 6 including a front cutting edge 6a and a side cutting edge 6b, and a rake face. 7. In this embodiment, the base 4 is made of a cemented carbide or high speed steel, and the blade 5 is made of a high hardness sintered body such as a diamond sintered body or a cBN (cubic boron nitride) sintered body. The blade portion 5 is more preferably made of a cBN sintered body that is frequently processed with difficult-to-cut materials. In FIG. 1, the blade portion 5 is brazed to the base portion 4 by two brazing portions 8 including a rear brazing portion 8a and a lower brazing portion 8b. The blade portion 5 in FIG. 1 and the blade portion 15 in FIG. 2 are shown in gray for convenience.

According to this embodiment, the ratio (L _f / L _b ) between the length L _{b of} the base portion 4 on the front cutting edge 6a side and the length L _f of the front cutting edge 6a of the blade portion 5 is 0.4 to 1. And the ratio (L _f / L _s ) between the length L _f of the front cutting edge 6a and the length L _s of the horizontal cutting edge 6b is 2 or less, and the front cutting edge 6a and the horizontal cutting edge 6b The cutting edge angle θ which is an angle formed by the angle is 60 to 83 °. As a result, it is possible to efficiently dissipate the cutting heat generated by the inner diameter machining of the difficult-to-cut material from the blade portion to the rake face and reduce the temperature rise of the blade portion. Progress can be suppressed and the cutting performance of the blade portion is maintained.

That is, when the ratio (L _f / L _b ) is smaller than 0.4, the heat dissipation of the blade portion 5 is lowered, the temperature of the cutting blade 6 is increased, and the cutting depth during cutting cannot be increased. Will be limited. A more preferable range of the ratio (L _f / L _b ) is 0.5 to 0.7 in terms of heat dissipation and cost. If the ratio (L _f / L _s ) is larger than 2 or the blade edge angle θ is smaller than 60 °, the cutting heat generated during cutting cannot be efficiently diffused into the blade portion 5, and the blade portion 5 Temperature tends to increase. That is, the heat generated at the portion of the cutting edge 6 and the rake face 7 where the chips come into contact diffuses relatively quickly in the blade portion 5. However, since heat propagation is poor in the brazing part 8 and the base part 4, the heat dissipation to the outside of the blade part 5 is reduced. Therefore, the shape of the blade portion 5 is long in both length and width with respect to the portion in contact with the work material so that heat is efficiently diffused, which is effective in improving the heat dissipation of the blade portion 5. It is. Furthermore, when the cutting edge angle θ exceeds 83 °, chips are clogged in the vicinity of the cutting edge 6 and become easy to bite into the cutting edge 6. A more preferable range of the ratio (L _f / L _s ) is 0.8 to 1.5 in terms of heat dissipation and cost, and a more preferable range of the blade edge angle θ is that of heat dissipation and chip discharge. The point is 70 to 80 °.

The blade portion 5 has a main surface made of a triangle as shown in FIG. 1 or a rectangular flat plate shape as shown in FIG. In the embodiment of FIG. 1, the thickness t ₁ of the blade portion 5 is 0.5 to 1.5 mm, and the thickness t ₂ below the lower brazing portion 8 b of the base portion 4 is 0.5 to 2.0 mm. The base portion 4 below the lower brazing portion 8b receives a load at the time of cutting, alleviates the concentration of the load at the time of cutting on the brazing portion 8, and suppresses the dropping of the blade portion 5. Further, in another embodiment shown in FIG. 2, the base portion 4 is not provided below the blade portion 15, and the brazing portion 18 includes a rear brazing portion 18a and a side brazing portion 18c. By making the main surface of the blade part 15 into a quadrangle, a side brazing part 18c is added to the rear brazing part 18a to increase the brazing area and increase the brazing strength. This configuration is suitable, for example, Work piece diameter corresponding to the length L _b of the front cutting edge 6a side is small load during the following cutting 3mm base 4.

  Further, according to FIG. 1, the shank portion 2 is moved in the front end view while adjacent to the rising portion 10 adjacent to the base portion 4 of the cutting edge portion 3, the transition portion 11 adjacent to the rising portion 10, and the transition portion 11. It consists of a rod-shaped part 12 projecting further toward the corner 6 c than the part 11. The corner 6c between the front cutting edge 6a and the side cutting edge 6b of the cutting edge 6 protrudes outward from the outer periphery of the transition portion 11 in the front end view. Further, the corner 6c is located on the inner side of the outer periphery of the rod-like portion 12 in the front end view.

  The base part 4 of the cutting blade part 3 and the rising part 10 of the shank 2 function as a chip pocket for temporarily storing chips generated during cutting. In this embodiment, a step 14 is provided between the base 4 and the rising portion 10, and the base 4 has a lower height than the rising portion 10. The blade portion 5 has the same height as the base portion 4. According to this configuration, when supplying the cutting fluid at the time of cutting, the cutting fluid flows surely and efficiently to the base portion 4, and the cutting fluid can be reliably and efficiently supplied to the blade portion 5 following the base portion 4. it can. In this embodiment, the height Δt of the step 14 is comprised between 0.01 and 0.5 mm. The upper surface of the blade portion 5 is polished when the step 14 is produced. Even if a crack generated during brazing is present on the upper surface of the blade portion 5, the crack is thinned or eliminated by polishing. It is possible to suppress the welding of the work material to the blade portion 5 at the time of cutting, and the progress of crater wear can be suppressed.

  On the other hand, as shown in FIG. 3, the holder 20 is provided with a long insertion hole 21 into which the insert 1 is inserted from the distal end of the long holder 20, and the insertion hole 21 has an inclined surface of the insert 1. A positioning member 22 is provided in contact with 13.

  Moreover, according to FIGS. 1-3, the inclined surface 13 is provided in the end opposite to the edge part in which the cutting blade part 3 was provided, and insert 1 is inserted in the insertion hole 21 of the holder 20 from the inclined surface 13 side. Then, the positioning member 22 provided on the holder 20 is fixed in contact with the inclined surface 13 so as to come into contact with the line. According to this configuration, the positioning of the cutting blade of the insert 1 in the longitudinal direction and the rotation direction is easy and the accuracy is increased.

  According to FIG. 3, the outer peripheral surface of the holder 20 on the tip (first end) side of the holder 20 other than the positioning member 22, in addition to the positioning member 22, in order to suppress the dropping and rattling of the insert 1. A screw hole 24 penetrating from the insertion hole 21 to the insertion hole 21 is formed, and a screw member 25 is screwed into the screw hole 24 so that the outer peripheral surface of the shank portion 2 of the insert 1 is pressed and fixed at the tip of the screw member 25.

A plurality of positioning member mounting holes (not shown) for inserting the rod-shaped positioning members 22 are provided on the side surface of the holder 20. A rod-shaped positioning member 22 is inserted into one of the positioning member mounting holes. The reason why a large number of positioning member mounting holes are provided is to allow the amount of protrusion of the insert 1 to be adjusted as appropriate. The positioning member 22 only needs to be in contact with the inclined surface 13 of the insert 1 such as a pin or a screw material, has a rod shape, and may have any shape such as a cylindrical column or a polygonal column such as a triangular column. There is no particular limitation. Since a pin can be easily inserted and removed, the amount of protrusion of the insert 1 can be easily changed. In this embodiment, a pin is used as the positioning member 22. The positioning member 22 is also provided so that the axis of the positioning member 22 is perpendicular to the longitudinal direction of the insertion hole 21.

  The positioning member 22 is fixed by a method in which both ends of the cylindrical pin are clamped and fixed, or a screw in which one side end portion of the cylindrical pin is threaded and the threaded portion is provided in the holder 20. A method of screwing into a cut portion, a method of fixing one end of a cylindrical pin with a taper shape having an enlarged diameter, and abutting and fixing the tapered portion to a predetermined position of the positioning member mounting hole, and fixing the cylindrical pin with an adhesive And a method of tightening and fixing the screw member from the side surface of the cylindrical pin.

  The position of the positioning member 22 in the insertion hole 21 may be appropriately adjusted according to the insertion angle of the inclined surface 13 of the insert 1. The inclined surface 13 of the insert 1 and the positioning member 22 are brought into contact with each other so as to be in line contact. For example, when the positioning member 22 is a cylindrical pin, the insert 1 is mounted on the holder 20. The direction perpendicular to the longitudinal direction of the inclined surface 13 and the direction perpendicular to the longitudinal direction of the holder 20 on the outer peripheral surface of the positioning member 22 are configured to be parallel to each other. Thereby, stable and strong restraint is possible.

  As shown in FIGS. 3B and 3C, the holder 20 includes a coolant hole 28 for supplying coolant therein. 5C, at least two injection ports 29a and 29b for the coolant hole 28 are provided independently of the insert insertion hole 21. As shown in FIG. That is, the injection ports 29 a and 29 b and the insert insertion hole 21 are not connected in the front end view of the holder 20. In this embodiment, the shortest width Δt between the injection ports 29a and 29b and the insert insertion hole 21 is 0.005 to 5 mm. Further, the centers of the two injection ports 29a and 29b are located above the center of the circle when the insert insertion hole 21 is viewed from the tip. As a result, the traveling direction of the coolant sprayed from the two spray ports 29a and 29b is shifted downward due to gravity, so that the sprayed coolant drops on the shank portion of the insert at a high rate, and then the shank portion. Flows to the cutting edge side of the tip. Moreover, part of the coolant injected from the two injection ports merges and the traveling direction is bent in the direction toward the tip, so that the rate at which the coolant is supplied to the cutting edge portion 3 is further increased. A part of the rear of the coolant hole 28 is connected to a portion where the hole diameter of the insert insertion hole 21 is increased. Moreover, since the injection port 29 of the coolant hole 28 is provided independently of the insert insertion hole 21, when the insert 1 is inserted into the holder 20 from the insert insertion hole 21, the injection port 29 interferes with the insert 1. Is not caught on the inner wall surface of the insert insertion hole 21, and the insertion and removal of the insert 1 is smooth.

  Here, according to FIGS. 3 (a) and 3 (b), the tip shape of the holder 20 has a convex curve portion 26 that protrudes outward in a side view, and an injection port 29a, 29b is provided. That is, the front end shape of the holder 20 is wide in the rearward direction as viewed from the side, and has a curved line on the front end side or a straight line with no corners. In other words, the holder 20 has no corner at the tip. Thus, when coolant (cutting fluid) is supplied from the holder 20 toward the insert 1, as shown in FIG. 3 (b), the position of the injection port 29 is such that the upper side is rearward and the lower side is shifted from the front. Become. With this shape, the traveling direction of the coolant injected from the injection port 29 is corrected upward, so that it is possible to reduce a deviation amount in which the traveling direction of the coolant is shifted downward due to gravity.

In addition, when the inner diameter is processed, the coolant supplied from the upper side of the non-rotating insert 1 is below the insert 1 when the inner end of the processing hole of the rotating work material is closed. Since it is discharged out of the machining hole of the work material through the side, the circulation of the coolant is good. Therefore, chips generated during cutting can be smoothly discharged out of the system. As shown in FIG. 3, the coolant is not limited to the one in which the coolant hole 28 is provided in the holder 20, and the coolant is supplied to the blade portion 5 of the insert 1 separately from the holder. May be.

  1 to 3, the configuration of the insert 1 in which the cutting blade portion 3 is provided only at one end of the shank portion 2 has been described. However, the present invention is not limited to this, for example, The present invention can also be applied to inserts having blade portions provided at both ends of the shank portion 2.

Before cutting edge side of the base length L _b is 6.0 mm, an insert having a shape shown in FIG. 1, a shape shown in Table 1, using a cutting tool mounted on the holder of FIG. 3, the following conditions Cutting was performed and the cutting performance was confirmed. The height of the step of each sample was 0.1 mm.
Cutting method: Internal diameter processed work material: SKD11
Cutting speed: 200 m / min Feed: 0.02 mm / rev
Cutting depth: 0.07mm
Cutting state: wet evaluation method: The state of the cutting edge and the rake face of the insert after 30 minutes of cutting time was observed. Moreover, the processing time until chip disposal deteriorated was confirmed.

As shown in Table 1, sample Nos. With a ratio (L _f / L _b ) of 0.4 to 1. Sample Nos. 2 to 5 are out of this range. Compared to 1, crater wear was less and the cutting time was longer.

The length L _b is 6.0mm before cutting side of the base, at the height of the step is 0.1 mm, the insert changing the shape shown in Table 2, using a cutting tool mounted on the holder of FIG. 3, Cutting was performed under the same processing conditions as in Example 1 to confirm the cutting performance. Sample No. 9 is a top of a substrate made of cemented carbide described in the prior art 2, with one of the four apex angles having an obtuse V-shaped flat plate blade portion and an acute angle portion having a small blade edge angle as a cutting blade. Is brazed.

As shown in Table 2, a sample No. with (L _f / L _s ) of 2 or less was used. Samples Nos. 7 to 8 are out of this range. Compared to 6 and 9, crater wear was less and cutting time was longer. In addition, the V-shaped flat blade portion having an obtuse angle of one of the four vertex angles described in the prior document 2 is formed on a base material made of cemented carbide with an acute angle portion having a small blade edge angle as a cutting blade. Brazed sample no. In No. 9, chipping of the cutting edge also occurred.

Before cutting edge side of the base length L _b is 6.0 mm, the insert changing the shape shown in Table 3, using a cutting tool mounted on the holder of FIG. 3, the cutting under the conditions of Example 1 The cutting performance was confirmed. Sample No. For Nos. 10 to 13, a step with a height of 0.1 mm was provided. For No. 14, no step was provided between the base and the rising portion.

  As shown in Table 3, the sample no. In No. 10, crater wear progressed quickly. In addition, the sample no. In No. 13, chips were likely to be clogged around the cutting blade, and the chips were bitten and became incapable of cutting. On the other hand, Sample No. with a cutting edge angle θ of 60 to 83 °. 11, 12, and 14 had less crater wear and longer cutting time. It should be noted that sample no. 14 is a sample No. 14 provided with the step of Example 1. The cutting time was shorter than 4.

DESCRIPTION OF SYMBOLS 1 Insert 2 Shank part 3 Cutting edge part 4 Base part 5, 15 Cutting edge part 6 Cutting edge 6a Front cutting edge 6b Horizontal cutting edge 6c Corner 7 Rake face 8, 18 Brazing part 8a, 18a Back brazing part 8b Lower brazing part 18c side braze _{L b} base 4 before the cutting edge 6a side of the length _{L f} blade portion length _{L s} side cutting length of the blade 6b theta included angle 10 rising portion 11 transitions before the cutting edge 6a of 5 12 Bar-shaped part 13 Inclined surface 14 Step 20 Holder 21 Insertion hole 22 Positioning member 24 Screw hole 25 Screw member 26 Convex curve part 28 Coolant hole 29 (29a, 29b) Injection port

Claims (3)

It is substantially rod-shaped and comprises a shank portion that is substantially circular when viewed from the tip, and a cutting edge portion provided at the tip of the shank portion,
The cutting blade portion includes a base portion and a blade portion brazed to the base portion, the blade portion includes a cutting blade including a front cutting blade and a side cutting blade, and a rake face,
The ratio (L _f / L _b ) between the length L _{b of the} base portion on the front cutting edge side and the length L _f of the front cutting edge of the blade portion is 0.4 to 1, and the front cutting The blade edge angle, which is the angle between the front cutting edge and the side cutting edge, and the ratio (L _f / L _s ) of the blade length L _f to the length L _s of the side cutting edge is 2 or less θ is 70~80 ° Tona is,
At the tip of the shank part, a rising part is provided behind the base part provided following the blade part of the cutting blade part, and a step is provided between the base part and the rising part. The base has a lower height than the rising portion . The blade section in support Creating of claim 1, wherein the principal plane is the triangular or square flat plate. A cutting tool in which the insert according to claim 1 or 2 is inserted and fixed in a long insertion hole provided on the tip side of the holder.