JP5110400B2 - Replaceable cutting tool - Google Patents

Description

  The present invention relates to a cutting edge exchangeable cutting tool in which a circular insert that is prevented from rotating is detachably attached to a tool body.

The blade-tip-exchangeable tool using a circular insert has a problem that the circular insert rotates due to a cutting load on the cutting blade. Patent Documents 1 and 2 disclose techniques for preventing rotation. .
In Patent Document 1, a means for fixing a circular insert outer peripheral surface in contact with a receiving surface of a tool body and a bottom surface side of the circular insert are formed into a polygonal shape, and this polygonal shape is brought into contact with the tool main body. The technique which uses together and the means to prevent rotation is disclosed.
Patent Document 2 discloses a technique related to an anti-rotation tool holder in a blade-tip-exchangeable tool using a circular insert, and the anti-rotation stopper is temporarily attached to the tool holder.

Japanese National Patent Publication No. 11-508192 JP 2006-523541 A

However, when the number of rotation prevention surfaces is increased in order to increase the number of corners used, the area of the bottom surface of the circular insert is reduced in the cutting edge-exchangeable tools such as Patent Documents 1 and 2. For this reason, the contact area between the circular insert and the tool body is reduced, and the mounting state becomes unstable. In addition, there is a problem in that the strength of the cutting edge of the circular insert is reduced and the accuracy of mounting accuracy due to deformation of the receiving surface of the tool body with which the conical surface comes into contact due to cutting load.
SUMMARY OF THE INVENTION An object of the present invention is to provide a cutting edge-exchangeable cutting tool that prevents the circular insert from rotating and avoids deterioration of the accuracy of the receiving surface of the tool body without degrading the cutting edge strength of the circular insert and can be attached with high accuracy. Is to provide.

The cutting edge replaceable cutting tool of the present invention is a cutting edge replaceable cutting tool in which a circular insert is detachably mounted via a tool body and a screw member. The circular insert has an upper surface and the upper surface facing the upper surface. It has a disk shape having a bottom surface having a smaller diameter and a conical outer surface connecting the top surface and the bottom surface, the top surface is a rake surface, the outer peripheral surface is a flank surface, and the rake surface and the A cutting edge ridge is formed by the flank, and among the cross sections parallel to the bottom surface of the circular insert, a part of the cross section is a cross section including the shape of the concave portion when viewed from the top surface direction, and the concave portion is prevented from rotating. When the thickness of the circular insert is h, the upper end of the anti-rotation surface is below the position (2/3) h from the bottom surface, and the lower end of the anti-rotation surface is above near than the position from the bottom (1/10) h is, the circular insert The bottom surface of the circular insert is in contact with the seating surface of the tool body, the anti-rotation surface of the circular insert is in contact with the anti-rotation member of the tool body, and the contact is the recess of the anti-rotation surface. And the disk shape of the anti-rotation member, the anti-rotation member is incorporated in the tool body, and the anti-rotation member is fixed to the tool body by a fixing member. It is characterized by that.

By configuring as described above, the blade insert is replaceable so that the circular insert can be prevented from rotating and the accuracy of the receiving surface of the tool body can be avoided without degrading the strength of the blade insert of the circular insert. A cutting tool can be provided.

  According to the present invention, there is provided a blade-tip-exchangeable cutting tool capable of preventing the rotation of the circular insert and avoiding the deterioration of the accuracy of the receiving surface of the tool body without deteriorating the blade tip strength of the circular insert and reliably attaching the blade insert. Could be provided. In particular, it was effective in preventing rotation of a thin circular insert having a diameter of 12 mm or less and a thickness of 5 mm or less, and high-efficiency machining could be achieved.

The figure concerning the example of embodiment of the blade-tip-exchange-type cutting tool of this invention is shown. 2 shows a side view of the insert of FIG. FIG. 2 shows a bottom view of the insert of FIG. FIG. 3 shows a cross-sectional view of position A in FIG. 2. Sectional drawing of the B position of FIG. 2 is shown. Sectional drawing of the B position of FIG. 2 is shown. FIG. 3 shows a cross-sectional view of position C in FIG. 2. The insert which concerns on a reference example shows the state which contacted the rotation prevention member. The insert which concerns on a reference example shows the state which contacted the rotation prevention member. The insert which concerns on a reference example shows the state which contacted the rotation prevention member.

FIG. 1 is a diagram showing a schematic configuration of an example of a cutting edge-exchangeable cutting tool according to the present invention. The blade-tip-exchange-type cutting tool 1 is configured to fix the insert 3 to the tool body 2 with a set screw 10. The tool body 2 is formed with an insert fixing portion 11 for removably attaching the circular insert 3. The insert fixing portion 11 is provided with a receiving surface 12 for receiving the outer peripheral surface of the insert 3 and a seating surface 13 for receiving the bottom surface of the insert 3, and a set screw insertion hole 14 for inserting the set screw 10 is formed. A rotation preventing member 15 for preventing the circular insert 3 from rotating is incorporated in substantially the center of the two receiving surfaces 12 and fixed to the tool body 2 by a fixing member 16.
FIG. 2 is a side view of the insert 3 shown in FIG. FIG. 3 shows a bottom view of the insert 3 shown in FIG. The insert 3 has a disk shape and is provided with a mounting hole 9 into which a set screw 10 for fixing to the tool body is inserted at the center. Further, the circular insert upper surface 4 that becomes a rake face when mounted on the tool body 2 and the bottom surface 5 facing the upper surface 4 have a smaller diameter than the upper surface 4, and have a conical shape that connects the upper surface 4 and the bottom surface 5. The outer peripheral surface 7 becomes a first fixing surface for fixing to the tool body 2. A ridge line portion where the upper surface 4 and the outer peripheral surface 7 intersect with each other is a cutting edge 6, and a concave rotation prevention surface 8 is formed on the outer peripheral surface 7.
4 to 7 are sectional views parallel to the bottom surface 5 at positions A, B, and C shown in FIG. 4 and 7 are circular shapes having no recesses or the like on the outer periphery. As a first example, FIG. 5 showing a cross-sectional view of the position B in FIG. It has the shape to have. In FIG. 5, it has six recessed parts. As a second example, in FIG. 6 showing another form in the cross-sectional view at the position B in FIG. 2, the rotation preventing surface has a concave shape. If it is this shape, when making it contact | abut with the combination which makes a rotation prevention member disk shape, it becomes possible to enlarge both contact area and can acquire the outstanding rotation prevention effect. As described above, since the insert according to the present invention has at least one concave portion on the conical outer peripheral surface, a part of the cross section parallel to the bottom surface in the outer peripheral surface region is always in the upper surface direction. It has a cross-sectional shape including a concave shape when viewed from the top. Further, in the present invention, for example, as shown in FIGS. 5 and 6, in the cross section including the concave shape, the concave shape constituting the rotation preventing surface does not intersect with each other and the circular arc shape constituting the conical outer peripheral surface is formed. It forms so that it may adjoin through a part. For this reason, there is always a portion where the outer peripheral surface, which is the first fixed surface for mounting the insert, extends from the top surface to the bottom surface, so that it can be firmly mounted.

  In the present invention, as shown in FIG. 2, when the thickness of the insert 3 is h, the upper end of the concave shape that is the rotation preventing surface 8 is a bottom surface that is below the position of (2/3) h from the bottom surface 5. Provide on the side. By comprising in this way, the outer peripheral surface thickness from the insert upper surface 4 to a recessed part can be ensured (1/3) h or more, and blade edge strength can be maintained. On the other hand, the lower end of the recess is provided on the upper side above the position of (1/10) h from the bottom surface 5. By comprising in this way, the outer peripheral surface thickness of (1/10) h or more can be secured from the bottom surface of the insert, and the strength and the fixed area of the circular bottom surface which is the second fixed surface of the insert are maintained and secured. be able to. The anti-rotation surface 8 of the present invention needs to be provided within the range of the position (1/10) h to (2/3) h from the bottom surface. Furthermore, even if the rotation preventing surface 8 is provided within the range of (1/10) h to (2/3) h from the bottom surface 5, the circumferential width L of the rotation preventing surface 8 is as follows. It changes as the length in the thickness direction changes. Therefore, the rotation preventing surface 8 must be appropriately provided in a range in which an L value that can provide the rotation preventing effect can be secured.

FIG. 8 is a diagram of the first embodiment showing a state where the anti-rotation member 15 incorporated in the tool body and the anti-rotation surface 8 are in contact with each other, which is a cutting edge replacement type cutting tool in the embodiment of the reference example . is there. The rotation preventing member 15 provided on the tool body and the rotation preventing surface 8 are in contact with each other by fixing the insert to the tool body, and the rotation of the insert can be reliably prevented.
9, FIG. 10 is a indexable cutting tool according to an embodiment of the reference example, the embodiment of the reference example showing how the rotation preventing member 17 and the rotation preventing surface 8 that incorporates the tool body is in contact FIG. The rotation preventing member 17 and the rotation preventing surface 8 provided on the tool main body come into contact with each other by fixing the insert to the tool main body, and the rotation of the insert can be reliably prevented. In FIG. 9, the rotation prevention member 17 and the rotation prevention surface 8 are in contact with each other, whereas in the embodiment of the reference example of FIG. 10, two rotation prevention members 17 are provided. This is an example in which two rotation prevention surfaces are in contact. According to the embodiment of the reference example , the rotation preventing member 17 can be provided at a plurality of locations. In particular, when the diameter of the insert is larger than 12 mm, the rotation of the insert can be more reliably prevented by using a plurality of rotation preventing members, which is preferable.
Moreover, since the conical outer peripheral surface is continuously present from the upper surface side to the bottom surface side despite the presence of the recess, the insert can be firmly fixed. As described above, the cutting edge-exchangeable cutting tool of the present invention can secure the outer peripheral surface thickness from the bottom surface of the insert, can maintain the strength and fixed area of the circular bottom surface that is the second fixed surface of the insert, and from the top surface of the insert. A sufficient thickness of the outer peripheral surface up to the recess can be secured. Since the circular insert according to the present invention has a small decrease in the strength of the blade edge even when the size is reduced, and has a rotation preventing surface 8 and can form a conical outer peripheral surface not only on the upper surface side but also on the bottom surface side, The wear and deformation of the receiving surface, which is the circular insert fixing portion of the tool body, can be reduced, and the durability of the tool body is improved. As a result, it is possible to repeatedly attach the circular insert with high accuracy. Furthermore, the combination of the circular insert and the tool body according to the present invention can provide a highly reliable cutting edge exchangeable cutting tool that can prevent the circular insert from rotating. As a result, highly efficient machining can be achieved.

  Hereinafter, although the cutting edge exchange type cutting tool of the present invention will be described in detail with reference to the following examples, the present invention is not limited thereby.

  The tool body has a bore shape having a cutting edge diameter of 50 mm, a hole diameter of the inlay portion of 22.225 mm, a length of 50 mm, and a three-blade. The base material of the tool main body was subjected to lathe machining using an SCM440 equivalent material and the surface shape was tempered from HRC 40 to 43, and then the mounting surface with the arbor and the inlay portion were finished by polishing. The insert fixing part was formed by milling at a machining center. The anti-rotation member was prepared by turning the SKD11 material to a surface hardness HRC58 to 60 after turning the SKD11 material and turning the outer diameter portion to a diameter of 2.5 mm. As the fixing member, a commercially available hexagon socket set screw M3 was prepared. After the rotation preventing member was inserted into the tool body, the fixing member was tightened to fix the rotation preventing member.

  The circular insert of Example 1 of the present invention was made of cemented carbide, the inscribed circle dimension was 12 mm, the thickness dimension was 4.76 mm, and the clearance angle of the outer peripheral surface with respect to the upper surface was set to 15 degrees. The rotation preventing surface was formed in the range of (2/3) h to (1/10) h from the bottom surface of the circular insert, and four surfaces were provided in the circumferential direction of the outer peripheral surface. A rotation preventing member (manufactured by SKD11) was brought into contact with one of the surfaces, and the circular insert was fixed to the tool body using a set screw. In addition, in Example 2 of the present invention, except that the rotation preventing member is made of cemented carbide, a tool body of the same shape and material as in Example 1 of the present invention is inserted into the tool body of the same shape and material as in Example 1 of the present invention. Installed. In Invention Examples 3 and 4, the number of rotation preventing surfaces is 6 and 8 respectively. Inventive Examples 5 to 7 have inscribed circle dimensions of 10 mm and different numbers of rotation prevention surfaces, and Inventive Examples 8 to 10 have inscribed circle dimensions of 8 mm and different numbers of rotation prevention surfaces. Show. The bottom surfaces of the circular inserts of Invention Examples 1 to 10 were all circular.

  In Comparative Example 11, the rotation preventing surface of the circular insert was formed in the range of (2/3) h to (8/100) h from the bottom surface of the circular insert. In Comparative Example 12, the rotation preventing surface of the circular insert was formed in the range of (2/3) h to (5/100) h from the bottom surface of the circular insert. That is, the lower end of the rotation preventing surface of Comparative Example 11 and Comparative Example 12 was in a state of being close to the bottom surface of the insert. In Conventional Examples 13 to 21, the rotation preventing surface was formed in the range of (2/3) h to 0h from the bottom surface of the insert. That is, the lower end of the rotation preventing surface of Conventional Examples 13 to 21 reached the bottom surface of the insert. Accordingly, none of the bottom surfaces of the inserts of the conventional examples 13 to 21 were circular, and the contact area was reduced. As will be described later, this is apparent from a comparison between the P value in Table 1 indicating the area of the bottom surface of the circular insert and the Q value in Table 2 indicating the area of the bottom surface of the polygonal insert.

Table 1 shows the bottom surface of the circular insert when the outer diameter, thickness h, clearance angle, mounting hole diameter, number of rotation prevention surfaces, etc. of the inserts of Invention Examples 1 to 10 and Comparative Examples 11 and 12 are specified. The area was shown as P value. For example, Invention Examples 1 to 4 indicate that the inscribed circle size of the insert is 12 mm and the bottom surface is circular, and the P value is 50.9 mm ² . Similarly, when the inscribed circle dimension is 10 mm as in Invention Examples 5 to 7, the P value is 32.6 mm ² , and when the inscribed circle dimension is 8 mm as in Invention Examples 8 to 10, The P value is 25.7 mm ² .
Table 2 shows the area of the bottom surface of the polygonal insert as a Q value when the outer diameter, thickness h, clearance angle, mounting hole diameter, number of rotation prevention surfaces, etc. of the inserts of Conventional Examples 13 to 21 are specified. It was. For example, when the shape of the bottom surface is octagonal as in Conventional Example 13, the Q value is 42.9 mm ² , which is smaller than the P value of 50.9 mm ² of Invention Examples 1 to 4. Similarly, in the case of a hexagon as in Conventional Example 14, the Q value is 38.6 mm ² , and in the case of a tetragon as in Conventional Example 15, the Q value is 26.1 mm ^2, which is even smaller. It was.

As is clear from Tables 1 and 2, in the conventional examples 13 to 21, the bottom area decreases depending on the number of rotation preventing surfaces. On the other hand, according to the configuration of the present invention in which the bottom area of the circular insert is ensured to the maximum, the bottom area (P value) does not decrease even when the number of rotation prevention surfaces is increased. The bottom surface area is larger than in Examples 13-21. Particularly, for a small-diameter circular insert having a diameter of φ8 mm, when the number of anti-rotation surfaces is 4, the P value of 25.7 mm ² of Example 8 of the present invention and the Q value of Conventional Example 21 of 13 are obtained. When compared with 0.1 mm ² , Example 8 of the present invention is 1.96 times larger. Even if the anti-rotation surface speed of 8 surface, and 25.7 mm ² a P value of the present invention Example 10 is compared with the 20.9 mm ² is Q value of the conventional example 19, the direction of the present invention Example 10 Since the area of the bottom surface of 1.23 times can be secured, it can be seen that the insert can be reliably fixed.

Cutting evaluation was performed using the produced cutting edge exchangeable cutting tool. The cutting edge exchangeable cutting tool to which the circular insert or the polygonal insert of each example shown in Table 1 and Table 2 was respectively attached was attached to an arbor as a tool holder, and then attached to the spindle of the milling machine. The pocket shape was contoured using the following cutting condition 1. Thereafter, the accuracy deterioration of the receiving surface of the tool body was evaluated using a master insert. In the evaluation method, the cutting edge position before starting the machining was set to a reference value of zero, and the difference from the cutting edge position after the machining was finished was compared. In measuring the difference in the position of the cutting edge with the master insert, the tip of the cutting edge of the cutting edge replaceable cutting tool was used.
(Cutting condition 1)
Work material: SCM440 equivalent material, hardness HRC30
Cutting speed: 200 m / min Spindle speed: 1273 revolutions / min Cutting depth: 2 mm
Radial cutting width: 25mm
1 blade feed: 0.8mm
Table feed: 3055 mm / min Machining method: dry, contour processing

  From the results of measurement of accuracy deterioration by the master insert, it was found that in Examples 1 to 10 of the present invention, there was no change in the position of the cutting edge, and wear and deformation of the receiving surface and the seating surface of the tool body were not observed and were good. On the other hand, in Comparative Example 11, the amount of change in the edge position was 2 μm before and after use, and in Comparative Example 12 was 4 μm. Further, in the conventional examples 13 to 21, a difference of 7 μm to 10 μm occurred, and further, contact marks with brown color were observed on the receiving surface and the seating surface of the tool body. This indicates that the receiving surface of the tool body is deformed and the circular insert cannot be attached with high accuracy.

  The tool body has a bore shape having a cutting edge diameter of 63 mm, a hole diameter of the inlay portion of 22.225 mm, a length of 50 mm, and a three-blade. The base material of the tool body was made of the same material as in Example 1 and finished by the same lathe processing and surface hardness adjustment, followed by polishing. The insert fixing part was formed by milling. The anti-rotation member was also made of the same material as in Invention Example 1, and finished into a disk shape by lathe processing and polishing. As the fixing member, a commercially available hexagon socket set screw was prepared. After the rotation preventing member was incorporated into the tool body, the fixing member was tightened to fix the rotation preventing member.

  The circular inserts of Invention Examples 22 to 24 were made of cemented carbide, and the inscribed circle dimension was 16 mm, the thickness dimension was 4.76 mm, and the clearance angle of the outer peripheral surface with respect to the upper surface was set to 15 degrees. The rotation preventing surface was formed in the range of (2/3) h to (1/10) h from the bottom surface of the circular insert. Four rotation prevention surfaces of Invention Example 22 were provided in the circumferential direction of the outer circumferential surface. One of them was brought into contact with the rotation preventing member 17 and the circular insert was fixed to the tool body using a set screw. In addition, in Invention Examples 23 and 24, the number of rotation prevention surfaces is 6 and 8 respectively. Two of them were brought into contact with the rotation preventing member 17 and the circular insert was fixed to the tool body using a set screw. The bottom surfaces of the circular inserts of Invention Examples 22 to 24 were all circular.

Cutting evaluation was performed using the produced cutting edge exchangeable cutting tool. A cutting edge exchangeable cutting tool with a circular insert shown in Table 3 was attached to an arbor as a tool holder, and then mounted on the spindle of the milling machine. The pocket shape was contoured using cutting condition 2 shown below. Thereafter, accuracy degradation of the receiving surface of the tool body was evaluated using the same evaluation method as in Example 1. The evaluation results are shown in Table 3.
(Cutting condition 2)
Work material: SCM440 equivalent material, hardness HRC30
Cutting speed: 200 m / min Spindle speed: 1011 revolutions / min Cutting depth: 2 mm
Radial cutting width: 25mm
1 blade feed: 0.8mm
Table feed: 3055 mm / min Machining method: dry, contour processing

  From the accuracy deterioration measurement results with the master insert shown in Table 3, in the inventive examples 22 to 24, there was no change amount of the cutting edge position, and satisfactory results were obtained. Similarly to Example 1, it was found that the receiving surface and the seating surface of the tool main body were not worn or deformed by visual observation and were good. Furthermore, when a detailed observation was performed using a stereomicroscope when the magnification was 30 times, only a slight brown contact mark was observed on the receiving surface and the seating surface of the tool body of Example 22 of the present invention. On the other hand, the receiving surface and the seating surface of the tool bodies of Invention Examples 23 and 24 were good. From this, it was found that when the diameter of the insert is as large as 16 mm, the rotation of the insert can be more reliably prevented by using a plurality of rotation preventing members, which is preferable.

  The cutting edge replaceable cutting tool of the present invention has a relatively small diameter, and prevents rotation of the circular insert attached to the tool body by contacting the anti-rotation surface and the anti-rotation member when using a thin circular insert. In addition, the bottom surface and the outer peripheral surface of the circular insert can be designed wider. Therefore, since wear and deformation of the receiving surface of the tool body due to cutting load can be suppressed, industrial applicability is improved for a cutting edge exchangeable cutting tool that performs high-precision and high-efficiency machining.

DESCRIPTION OF SYMBOLS 1 Cutting edge exchange type cutting tool 2 Tool body 3 Insert 4 Upper surface 5 Bottom surface 6 Cutting blade 7 Outer peripheral surface 8 Rotation prevention surface 9 Mounting hole 10 Set screw 11 Insert fixing | fixed part 12 Seating surface 14 Seating surface 14 Set screw insertion hole 15 Rotation Prevention member 16 Fixed member 17 Anti-rotation member A Position in the insert thickness direction B Position in the insert thickness direction C Position in the insert thickness direction L Width in the circumferential direction of the anti-rotation surface

Claims (1)

In the cutting edge replaceable cutting tool in which a circular insert is detachably mounted via a tool body and a screw member, the circular insert has an upper surface, a bottom surface facing the upper surface and having a smaller diameter than the upper surface, the upper surface and the upper surface. A disc shape having an outer peripheral surface formed in a conical shape connecting the bottom surface, the upper surface is a rake surface, the outer peripheral surface is a flank surface, and a cutting edge ridge is formed by the rake surface and the flank surface, Among the cross sections parallel to the bottom surface of the circular insert, a part of the cross section is a cross section including the shape of the concave portion when viewed from the top surface direction, and the concave portion is a rotation preventing surface, and the thickness of the circular insert H, the upper end of the anti-rotation surface is below the position (2/3) h from the bottom surface, and the lower end of the anti-rotation surface is a position (1/10) h from the bottom surface. above near than is, the seating surface of the bottom surface of the circular insert the tool body The anti-rotation surface of the circular insert is in contact with the anti-rotation member of the tool body, and the contact includes the shape of the concave portion of the anti-rotation surface and the anti-rotation member. A cutting edge-replaceable cutting tool which is in contact with a combination of a disk shape, the rotation preventing member is incorporated in the tool body, and the rotation preventing member is fixed to the tool body by a fixing member. .

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