JP3214963B2 - Indexable tip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away chip in which two opposing surfaces are parallel to each other in a circular shape in plan view.

[0002]

2. Description of the Related Art Conventionally, in a turning and boring system, there is a cutting tool used for inner and outer diameter machining of a workpiece. As an example of this kind of tool, there is a cutting tool to which a disc-shaped indexable insert is attached as shown in FIGS. 10 and 11, for example. The disc-shaped indexable insert 1 has a circular shape in plan view, is parallel to the upper surface 3 facing the lower surface 2 with the seating surface 2 facing, and the circular ridge line of the upper surface 3 is the cutting edge 4.
The peripheral surface 5 is formed in a tapered shape whose diameter gradually decreases from the upper surface 3 to the lower surface 2. A tapered mounting hole 7 into which the head of the flat head screw 6 is fitted partway is formed in the center of the upper surface 3. In the cutting tool shown in the figure, a tip seat 9 composed of, for example, a substantially rectangular concave portion in a plan view is formed on the tip end surface of the tool main body 8, and the above-described disc-shaped throw-away tip 1 is formed on the tip seat bottom surface 9a. The disc-shaped throw-away tip 1 is fixed to the tip seat 9 with a flat head screw 6. In addition, the indexable insert 1 is positioned such that the peripheral side surface 5 is in contact with the corners of the tip seat side walls 9b, 9b of the tool body 1.

[0003] When cutting the work material, the cutting is performed by the cutting edge 4 of the disc-shaped indexable insert 1 fixed and held as described above, and if the insert is worn or the cutting edge is broken. Then, the flat head screw 6 is loosened to change the mounting angle position of the chip 1 for cutting.

[0004]

In order to improve the productivity of cutting, it is effective to shorten the actual cutting time by high-speed cutting. However, turning of steel or the like generally has a drawback that when cutting at high speed, the life of the cutting edge of the tool becomes extremely short. Similarly, in the above-mentioned disc-shaped insert insert, there is a problem that the wear of the insert is large and the time for continuous processing is short.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a throw-away insert which has a small amount of wear even at high-speed cutting and can greatly improve the life of the insert.

[0006]

The indexable insert according to the present invention has the shape of a disk having two concentric circular surfaces parallel to each other, and a cutting edge is formed on the ridge line of at least one of the circular surfaces. and with which a cylindrical central shaft is protruded respectively at the center of the circular face, among them
The center axis is rotatable in the shaft hole provided in the rotary tool.
By mating, it is raised by cutting resistance during turning.
It is characterized by being driven and rotated about the central axis .

[0007] Further, the present invention is characterized in that the disk shape is a column shape.

[0008] The invention is characterized in that the cutting blade is a honing blade.

[0009]

In the turning operation, the frictional resistance between the running chip and the rake face of the insert is reduced due to the driven rotation of the indexable insert about its central axis by the cutting resistance, so that the wear of the insert is small. Moreover, since the coaxiality between the center axis and the cutting blade is high, the cutting accuracy during the driven rotation is high.

[0010] Since the cutting blade is a honing blade, the strength of the cutting blade is further improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front view of a throw-away tip according to the present embodiment, FIG. 2 is a plan view, and FIG. 3 is an enlarged view of a cutting blade portion in FIG. The indexable insert 11 has a concentric circular upper surface 12 and a lower surface 13 which are parallel to each other, have the same diameter, and are concentric.
And a peripheral side surface 14. or,
Honing is performed on one or both ridges of the upper and lower surfaces 12 and 13 as shown in FIG. 3, and a cutting edge 15 (a honing blade) is provided on a circular ridge where the chamfered portion 12a and the peripheral side surface 14 intersect. Have been. In this embodiment, the inclination angle of the chamfered portion 12a with respect to the upper surface 12 is set to, for example, 25 °, but this angle may be set to an appropriate value. or,
At the centers of the upper and lower surfaces 12, 13, small-diameter cylindrical central shafts 16a, 16b are formed to protrude, respectively. The indexable insert 11 rotates about central axes 16a and 16b, and the cutting edge 15 (peripheral side surface 14) rotates with the central axes 16a and 16b.
16b has a concentric axis.

Next, the structure for attaching the indexable insert 11 to the cutting tool according to the present embodiment will be described with reference to FIGS. 4 is a perspective view of a main part of a rotary tool, FIG. 5 is a longitudinal sectional view, FIG. 6 is a perspective view of a main part viewed from a direction different from FIG. 4, and FIG. 7 is a view showing a relationship between a rotary tool and a work material. is there. In the rotary tool 17 shown in FIGS. 4 to 7, a notch 20 is formed by notching a tip surface 19 a of a projection 19 formed at the tip of a tool body 18. A chip seat 21 is formed by further cutting a corner of the cutout portion 20 into a substantially fan shape in plan view.

On the bottom surface of the tip seat 21 of the tool body 18,
A through-hole 22 penetrating the protrusion 19 is formed, and a substantially columnar sheet portion 23 having a flange 23a having substantially the same diameter as the throw-away tip 11 is inserted into the through-hole 22.
The flange 23a is seated on the bottom surface of the chip seat 21. A shaft hole 23b is formed in the center of the surface of the flange portion 23a of the seat portion 23. The center shaft 16b is rotatably fitted in the shaft hole 23b, and the above-described indexable tip 11
Is seated on the collar 23a. A plurality of recesses 25 are provided in the circumferential direction in the vicinity of the center in the longitudinal direction of the seat portion 23 so as to be dispersed in the circumferential direction, and a locking screw 26 screwed into a screw hole penetrating from the projection portion 19 to the through hole 22 is provided. By fitting into the concave portion 25 of the tool body 1, the seat portion 23 is
Fixed to

The notch 20 of the projection tip surface 19a
Is fitted with a clamp breaker 27, and a clamp screw 28
Has been fixed by. A part of the clamp breaker 27 extends to the area of the upper surface 12 of the throw-away chip 11, and the central axis 16 of the
Pressing portion 27 having shaft hole 27a into which a rotatably fits
b is formed, and the throw-away tip 11 is pressed by the pressing portion 27b. A cylindrical brake collar 29 having a U-shaped cross section is provided between the clamp breaker 27 and the head 28a of the clamp screw 28. A hole 30 is formed in a region around the clamp screw 28 of the clamp breaker 27, and an annular collar 31 having an L-shaped cross section through which the clamp screw 28 passes is disposed in the hole 30. The upper end is in contact with the lower surface of the brake collar 29. A brake washer 33 is provided on the upper surface of the clamp breaker 27 on the outer periphery of the annular collar 31.
Are fitted and mounted, and a wave washer 34 is interposed between the brake washer 33 and the brake collar 29 in a compressed state.

A cylindrical stepped recess 36 is formed around the clamp screw 28 of the notch 20 of the projection 19, and a flange of the annular collar 31 is located at the wide portion, and at the narrow portion. A coil spring 37 for resiliently pressing the flange of the annular collar 31 is disposed on the outer periphery of the clamp screw 28 and urges the annular collar 33, that is, the clamp breaker 27, in a direction away from the throw-away tip 11. Thus, the pressing force of the throw-away tip 11 by the pressing portion 27b of the clamp breaker 27 is set based on the difference between the urging forces of the wave washer 34 and the coil spring 37. To adjust this pressing force, use brake washer 3
What is necessary is just to replace 3 with a thing with a different thickness.

In the indexable insert 11 attached to the tool body 18, the back rake angle is set to -6 ° at the position where the work material is cut (see FIG. 4), and the lateral rake angle is set to-. 36 ° (see FIG. 6). In the case of the present embodiment, since the portion of the throw-away tip 11 excluding the central axes 16a and 16b is cylindrical, the back rake angle is necessarily negative.
In addition, in order to rotate the throw-away tip 11 by cutting resistance during cutting, it is necessary to set the lateral rake angle to be negative. When the back rake angle is -6 °, a cutting tool to which a cylindrical throw-away tip similar to the throw-away tip 11 is fixed is used to cut the lateral rake angle at which the wear of the tip 11 and the cutting resistance are minimized. According to a test, it was found to be -36 °. At this lateral rake angle of -36 °, the cutting force is the lowest, and it is considered that the balance of each component such as the main component and the feed component is the most stable. However, this side rake angle is -3
The angle is not limited to 6 °, and an appropriate angle can be set. Note that this preferable side rake angle varies when the value of the back rake angle changes.

Since the present embodiment is constructed as described above, for example, a steel work material W as shown in FIG. 7 is processed at a high speed by using the rotary tool 17 provided with the indexable insert 11 according to the present embodiment. Turning with. Then, since the lateral rake angle is set to be negative, the indexable tip 11 is driven to rotate by the cutting resistance of the workpiece W. Therefore, the frictional resistance between the chips generated by the cutting and traveling and the rake face of the chip 11 is reduced. At this time, the indexable insert 11 is provided with the clamp breaker pressing portion 27b and the shaft holes 27a,
The center shafts 16a and 16b fitted to the shaft 23b are driven to rotate around the center. In this case, throw away tip 1
Since the central axes 16a and 16b and the cutting edge 15 (peripheral side surface 14) have high coaxiality, high-precision rotation and cutting can be performed. Therefore, the finished surface roughness of the workpiece is equivalent to that of the cutting tool to which the above-mentioned cylindrical indexable insert is fixed.

Further, since the indexable insert 11 is elastically pressed by the pressing portion 27b of the clamp breaker 27, the indexable insert 11 caused by cutting resistance is used.
Is suppressed so as not to become faster than necessary. Note that the driven rotation speed of the throw-away tip 11 can be appropriately adjusted by the pressing force of the pressing portion 27b. In this case, the adjustment of the pressing force of the throw-away tip 11 by the pressing portion 27b is performed by replacing the brake washer 33 with an appropriate thickness. Thereby, the elastic force of the wave washer 34 when the clamp screw 28 is tightened can be increased or decreased.

When the indexable insert 11 is cut, the insert 11 is pressed by the cutting resistance, and
The abutting portions a and 16b and the wall surfaces of the shaft holes 27a and 23b of the seat portion 23 and the shaft holes 27a and 23b of the seat portion 23 are worn, which may hinder the high-precision driven rotation of the tip 11 in which the shaft is not displaced. Can occur. In such a case, if the locking screw 26 is loosened and the seat portion 23 is rotated by a predetermined angle, another recess 25 is made to face the locking screw 26, and the seat portion 23 is screwed and the seat portion 23 is fixed. The precision of the driven rotation and cutting of the tip 11 is maintained.

It is to be noted that a rotary tool 17 provided with the indexable tip 11 according to the present embodiment, and a tool to which a columnar indexable tip similar to the tip 11 is fixed,
In the bytes triangular chip is fixed, in the case of processing a workpiece such as steel, and each of the flank wear width V _B, when comparing test and cutting resistance F, respectively Figure 8, the results shown in FIG. 9 Obtained. In the drawing, the line indicated by the symbol A is the one with the rotary tool 17 according to the present embodiment, the symbol B is the one with the cylindrical indexable tip fixed, and the symbol C is the one with the triangular tip fixed. Points to something. In the graph shown in FIG. 8, it can be seen that the rotary byte 17 is extremely small flank wear width V _B as compared to other two-byte according to the embodiment. In addition, in the graph shown in FIG.
Is because the indexable tip 11 is driven to rotate,
The cutting resistance F is slightly smaller than that of a cutting tool in which a similar cylindrical tip is fixed.

As described above, according to the indexable insert 11 of the present embodiment, even when the indexable insert 11 is mounted on the rotary tool 17 and the turning of steel or the like is performed at a high speed, the indexable insert 11 is driven by the cutting resistance so that By doing so, the frictional force between the chips and the rake face is reduced, the wear of the chip 11 is reduced, and the life of the chip 11 can be greatly extended. In addition, the finished surface roughness of the workpiece is equivalent to that obtained by cutting with the same disk-shaped chip fixed. Further, the indexable insert 11 has a high concentricity of the circular cutting blade 15 when driven to rotate around the center shafts 16a and 16b projecting from both surfaces thereof, so that high-precision cutting can be performed.

Incidentally, the throw-away tip 11 does not necessarily need to be formed in a cylindrical shape as in the above-described embodiment.
For example, as shown in the above-described prior art, the peripheral side surface may be formed in a tapered shape, the diameter of the lower surface 13 may be small, and the central axes 16a and 16b may be formed at the center of the upper and lower surfaces 12 and 13. . Honing is not necessarily performed on the ridges of the upper and lower surfaces 12, 13 of the throw-away tip 11, and the cutting edge 15 may be provided on the ridges.

[0023]

As described above, the indexable insert according to the present invention has a disk shape having two concentric circular surfaces parallel to each other, and at least one of the circular surfaces has a cutting edge on a ridge line. together are formed, cylindrical central shaft is protruded respectively at the center of the circular face, among them
The center axis is rotatable in the shaft hole provided in the rotary tool.
By fitting, on the cutting resistance at the time of turning
Since those driven to rotate around the serial central axis, it can be rotated and cutting with high accuracy. In addition, the driven rotation can significantly reduce the wear of the chip and extend the life of the chip. In addition, the finished surface roughness of the workpiece is equivalent to that obtained by cutting with the same chip fixed. Further, since the cutting blade is a honing blade, the strength of the cutting blade can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a throw-away tip according to the present invention.

FIG. 2 is a plan view of the throw-away tip of FIG.

FIG. 3 is an enlarged view of a cutting edge portion of the indexable insert of FIG. 1;

FIG. 4 is a perspective view of a main part of a rotary tool to which a throw-away tip according to the embodiment is mounted.

FIG. 5 is a longitudinal sectional view of the rotary tool shown in FIG. 4;

6 is a perspective view of a main part of the rotary cutting tool of FIG. 4 viewed from a direction different from that of FIG. 4;

FIG. 7 is a perspective view showing a relationship between a rotary tool and a work material in FIG. 4;

FIG. 8 is a diagram showing a relationship between a flank wear width and a cutting time by each cutting tool.

FIG. 9 is a diagram showing the relationship between cutting resistance and cutting time by each cutting tool.

FIG. 10 is a plan view of a conventional cutting tool provided with a disc-shaped indexable insert.

FIG. 11 is a side view of the cutting tool according to FIG. 10;

[Explanation of symbols]

 11 Indexable insert 12 Upper surface 13 Lower surface 15 Cutting edge 16a, 16b Central axis

──────────────────────────────────────────────────続 き Continuing on the front page (72) Tomoyoshi Sakamoto, Inventor: 1151 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture Inside the Tsukuba Works, Mitsubishi Materials Corporation (72) Inventor: Hiroyuki Takahashi 1151, Furamaki, Ishishita-cho, Yuki-gun, Ibaraki Prefecture Mitsubishi Materials Corporation Tsukuba Works (56) References JP-A-54-291 (JP, A) JP-A-57-201104 (JP, A) Full-fledged Showa 54-156889 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B23B 27/16 B23B 27/12 B23B 27/00 B23B 27/08 B23B 27/14

Claims (3)

(57) [Claims] 1. A disk shape having two concentric circular surfaces parallel to each other, wherein a cutting edge is formed on a ridge line of at least one of the circular surfaces, and a center portion of each circular surface is formed.
Column-shaped central axes are respectively formed to protrude ,
The shaft is rotatably fitted into the shaft hole provided in the rotary tool.
By turning, the cutting resistance
A throw-away tip characterized by being driven to rotate about a central axis . 2. The indexable insert according to claim 1, wherein said disk shape is a column shape. 3. The indexable insert according to claim 1, wherein the cutting blade is a honing blade.