JPH10277829A - Turning cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an excellent machined surface accuracy without entailing any uncut part in checking the backward movement of a cutting edge by installing a weight on the peripheral part side of a surface facing to the rear end side of a tool body. SOLUTION: A weight 24 is installed on the side of a peripheral part 12 of a surface facing to the rear end side of a tool body 11 in having an interval opened to the peripheral side in a gap with a boss part 23. Accordingly, if any deformation is produced by dint of centrifugal force in the tool body 11 due to its rotation at high speed, in the case where a centroidal position of the peripheral part 12 of the tool body 11 is in the same position of another centroidal position at the side of an inner circumferential part in the axial O direction, the peripheral part 12 is merely deformed so as to be spread at the peripheral side, so that in this tool body 11, a position in the axial O direction of each cutting edge 18 at the tip side remains unchanged. In consequence, there is no uncut part in a work material, and thus a good machined surface is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a milling tool, such as a face mill, provided with a cutting edge on the outer periphery of a tip end of a tool body rotated about an axis.

[0002]

2. Description of the Related Art For example, FIG.
And a throw-away type face mill as shown in FIG. 8 are known. In such a throw-away type face milling machine, a plurality of chip pockets 2 are formed at equal intervals in the circumferential direction of the tool main body 1 on the outer peripheral portion of the disk-shaped tool main body 1 centered on the axis O. At the same time, chip mounting seats 3 are formed on the wall surfaces of the chip pockets 2... Facing the tool rotation direction side, and the flat cutting inserts 4 are provided with the cutting edges 5 on the chip mounting seats 3. It is configured to protrude from the tool main body 1 to the tip side (the lower side in each figure) and to be detachably mounted. The tool body 1 is formed such that the surface 6 facing the rear end side (upper side in each drawing) is formed into a flat conical surface so that the tool body 1 generally becomes thicker toward the inner peripheral side in order to secure tool rigidity. ing.

In the face mill shown in FIGS. 7 and 8, a mounting hole 7 for mounting the face mill on an arbor mounted on a main shaft of a machine tool is provided at the center of the tool body 1. The tool body 1 is formed so as to penetrate along the axis O. And in the face milling machine configured as described above, the tool body 1
Is attached to the main shaft of the machine tool via an arbor attached to the attachment hole 7, is sent out in a direction perpendicular to the axis O while being rotated around the axis O in the tool rotation direction, and is attached to the tool body 1. The surface of the work material is cut flat by the cutting blades 5 of the plurality of indexable inserts 4. Here, in particular, in this type of face milling, in order to obtain good surface finish accuracy, the plurality of indexable inserts 4 mounted on the tool body 1 are arranged such that the positions of the cutting blades 5 are predetermined in the direction of the axis O. The run-out is strictly adjusted to match the position.

[0004]

In recent years, however, in order to increase the efficiency of cutting with such a rolling tool,
Alternatively, in the case of cutting an aluminum material or the like, in order to increase the cutting speed, the case where the tool body 1 is rotated at a high speed of 10000 rpm or more to perform cutting is increasing. The effect of the centrifugal force acting on the surface cannot be ignored. However, in a conventional milling tool such as the above-mentioned face mill, the surface 6 facing the rear end side of the tool body 1 has a conical shape as described above, and therefore, in the direction of the axis O of the tool body 1. Since the position of the center of gravity is such that the outer peripheral side is located on the distal end side with respect to the inner peripheral side of the tool main body 1, when a large centrifugal force due to high-speed rotation acts on such a tool main body 1, FIG. As shown by the broken line in FIG. 8, the outer peripheral portion of the tool main body 1 expands toward the outer peripheral side, and the tool body 1 is bent toward the rear end side so that the position of the center of gravity in the direction of the axis O coincides with the inner peripheral side, Thereby, the tool main body 1 is deformed so as to open the umbrella. This is particularly remarkable in a rolling tool in which the thickness of the tool body 1 is reduced for high-speed rotation cutting.

[0005] The deformation of the tool body 1 causes the position of the cutting blades 5 in the direction of the axis O to be changed.
Therefore, there occurs a problem that the surface of the work material is not cut to a predetermined depth of cut and the work material is left uncut. Incidentally, in the face milling machine as described above, the run-out in the direction of the axis O between the cutting edges 5 of the indexable inserts 4 attached to the tool body 1 is 0.03 mm or less in general finishing.
Also, when strict finish accuracy is required, 0.0
It is set to less than 2mm, but according to the experiment,
The tool body 1 of the above-mentioned conventional face mill is 10,000 r.
When rotating at a speed of more than 1 mm, a result of about 0.02 to 3 mm of uncut residue is obtained. That is, the runout accuracy is equal to or greater than the runout accuracy of the cutting edges 5. This means that the tool body 1 is deformed and the cutting blades 5 are retracted.

The present invention has been made under such a background, and in particular, suppresses retraction of a cutting blade due to deformation of a tool body during high-speed rotation, and achieves excellent surface finish without leaving uncut portions. It is an object of the present invention to provide a milling tool capable of obtaining the following.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve such an object, the present invention provides a cutting tool which is provided around a distal end of a substantially disk-shaped tool body which is rotated around an axis. In the milling tool provided, a weight is provided on an outer peripheral portion side of a surface facing a rear end side of the tool main body. Therefore, by adopting such a configuration, according to the present invention, the position of the center of gravity in the outer peripheral portion of the tool main body is substantially positioned without being located on the axial end side with respect to the position of the center of gravity in the inner peripheral portion side. It can be located at the same position or at the rear end side in the axial direction. For this reason, even if centrifugal force acts on the tool body due to high-speed rotation, the tool body is not deformed when the center of gravity in the outer periphery is at the same position as the inner periphery in the axial direction. Even when the tool body is on the rear side in the axial direction from the side, the outer peripheral portion of the tool body is bent toward the front end in the axial direction due to centrifugal force, so that there is no uncut portion.

In the case where the weight is provided so as to protrude toward the rear end in the axial direction from the surface facing the rear end of the tool body, the weight has a greater specific gravity than the tool body. In addition to the material, it can be formed of a material having the same specific gravity as the same material as the tool body. Further, when a recess is formed on the outer peripheral side of a surface facing the rear end side of the tool body, and the weight is formed of a material having a higher specific gravity than the tool body, and is disposed in the recess.
The surface facing the rear end side of the tool body and the surface facing the rear end side of the weight can be formed flush.

On the other hand, when the weight is provided on the surface facing the rear end of the tool main body in an annular shape around the axis, the outer peripheral portion extends over the entire circumference of the tool main body. Deformation due to centrifugal force can be controlled so as not to bend to the side, but the problem such as deterioration of finished surface accuracy due to uncut parts due to such bending occurs due to the provision of the cutting edge in the tool body. For example, the weight is scattered in the circumferential direction of the tool main body so as to be located on the rear end side in the axial direction of the cutting edge of the surface facing the rear end side of the tool main body. May be provided. Further, if the weight is detachably attached to the tool main body, by changing the weight according to cutting conditions such as the rotation speed of the tool main body, it is possible to control the deformation of the tool main body according to the cutting conditions. Becomes possible.

[0010]

1 and 2 show a first embodiment of the present invention.
And shows a case where the present invention is applied to a face mill attached to an arbor as shown in FIG. In the face milling machine of the present embodiment, the tool body 11 is formed of a lightweight metal such as an aluminum material to reduce the weight according to the high-speed rotation, has a substantially disk shape around the axis O, and has an outer peripheral portion 12. A plurality of (four in this embodiment) tip pockets 1
Are formed at regular intervals in the circumferential direction of the tool body 11, and chip mounting seats 14 are formed on the wall faces of the chip pockets 13 that face the tool rotation direction. Each throwaway tip 1
5 is attached.

Here, the throw-away tip 15
Is a positive indexable insert formed in a substantially rectangular plate shape from a hard material such as a cemented carbide in the present embodiment, and one square surface is a rake face 16 and one of the rake faces 16 is The main cutting edge 17 is formed at the edge,
Further, at one corner of the main cutting edge 17, a finishing cutting edge (sub cutting edge or flat blade) 18 is formed so as to be orthogonal to the main cutting edge 17. The throw-away tip 15 turns the rake face 16 toward the tool rotation direction, causes the main cutting edge 17 to protrude toward the outer peripheral side of the tool body 11, and further connects the cutting edge 18 to the tip end face 19 of the tool body 11. Are arranged in a plane orthogonal to the axis O projecting from
It is detachably mounted on the chip mounting seat 14 by a clamp means such as a clamp screw 20.

On the other hand, the tip surface 19 of the tool body 11
In the present embodiment, it is formed as a plane orthogonal to the axis O. At the center of the tool body 11, a mounting hole 21 for mounting the front milling cutter on an arbor mounted on the main shaft of the machine tool is formed so as to penetrate the tool body 11 along the axis O. At the same time, the mounting hole 21 at the center of the surface 22 facing the rear end of the tool body 11
Is formed so as to be raised by one step from the outer peripheral portion 12 side of the surface 22 facing the rear end side, and the boss portion 23 is formed. In the present embodiment, the surface 22 facing the rear end side of the tool main body 11 is also formed as a surface orthogonal to the axis O like the front end surface 19.

A weight 24 is provided on the outer peripheral portion 12 side of the surface 22 facing the rear end side of the tool main body 11 with a space on the outer peripheral side between the boss portion 23 and the weight 24. In the present embodiment, the weight 24 is formed of a steel material or the like having a higher specific gravity than the aluminum material forming the tool main body 11, forms an annular shape (ring shape) around the axis O, and includes a clamp screw (not shown) or the like. It is detachably attached to the tool main body 11 by attaching means. The cross section of the weight 24 has a substantially rectangular shape flattened in the direction of the axis O as shown in FIG. 2, and its radial width with respect to the axis O is, as shown in FIG. And its outer peripheral surface 25
Is flush with the outer peripheral surface 26 of the tool body 11. Further, the thickness of the weight 24 in the direction of the axis O is smaller than the height of the boss portion 23 from the surface 22 facing the rear end side of the tool body.

In the face mill having the above-mentioned structure,
Outer peripheral portion 1 of tool body 11 provided with this weight 24
The position of the center of gravity G in the direction of the axis O in FIG. 2 is defined as the axis of the center of gravity H in the inner peripheral portion 27 of the tool body 11 between the boss portion 23 and the weight 24. Considering the weight of the throw-away tip 15 and the clamp screw 20 with respect to the position in the O direction,
It can be located at approximately the same position or at the rear end side of the tool body 11. Therefore, even if the tool main body 11 is deformed by centrifugal force due to the high speed rotation of the tool main body 11, the position of the center of gravity G of the outer peripheral portion 12 of the tool main body 11 is shifted to the position of the center of gravity H on the inner peripheral portion 27 side and the axis. When the tool main body 11 is substantially at the same position in the O direction, the tool main body 11 only deforms so that the outer peripheral portion 12 spreads to the outer peripheral side, so that the position of the cutting edge 18 on the distal end side in the axis O direction changes. Never do.

On the other hand, even when the center of gravity G of the outer peripheral portion 12 is located on the rear end side of the inner peripheral portion 27 in the direction of the axis O with respect to the center of gravity H, the outer peripheral portion 12 of the tool main body 11 is moved by the centrifugal force. The cutting edge 18 does not retreat as in the above-described conventional face milling machine because it is deformed so as to bend toward the tip end side of the tool body 11 with respect to the part 27 side. Therefore, according to the face milling machine of the present embodiment, even when cutting is performed by rotating the tool body 11 at a high speed, it is possible to obtain a good finished surface without leaving uncut portions in the work material. Becomes

Here, in this embodiment, the tool body 11 is formed of a lightweight metal such as an aluminum material as described above, whereas the weight 24 is formed of a steel material or the like having a higher specific gravity. However, when the weight 24 is provided so as to protrude toward the rear end in the axis O direction from the surface 22 facing the rear end of the tool body 11 as in the present embodiment, Even if the specific gravity is made equal by, for example, using the same material as that of the tool body 11, or the material is formed of a material having a smaller specific gravity than the tool body 11, the position of the center of gravity G on the outer peripheral portion 12 side of the tool body 11 in the axis O direction. It is possible to achieve the above-mentioned effects by positioning the position substantially equal to or at the rear end side of the center of gravity H on the inner peripheral portion 27 side. However, as in the present embodiment, the weight 24
Is formed of a material having a larger specific gravity than the tool body 11,
If the position of the center of gravity G is the same, the weight 24 can be reduced as compared with the case where the weight 24 is formed of a material having the same or smaller specific gravity. Surface 22
From the boss portion 23 to interfere with the arbor or the main shaft of the machine tool, or the outer peripheral surface 25 of the weight 24.
Can be prevented from protruding from the outer peripheral surface 26 of the tool body 11 and interfering with the work material.

When the weight 24 is made of a material having a specific gravity greater than that of the tool body 11,
As in the second embodiment of the present invention shown in FIGS. 3 and 4, a concave portion 31 is formed on the outer peripheral portion 12 side of the surface 22 facing the rear end side of the tool body 11, and the weight 24 is formed in the concave portion 31.
May be provided. That is, in the second embodiment, the concave portion 31 having a rectangular cross section is provided with the axis O at the intersection ridge line between the surface 22 facing the rear end side of the tool body 11 made of aluminum or the like and the outer peripheral surface 26. The weight 24, which is formed in an annular shape at the center and is made of a steel material or the like having a specific gravity greater than that of the tool body 11, is fitted into the recess 31 and then attached to the tool body 11 by attachment means such as a clamp screw (not shown). The surface 32 and the outer peripheral surface 25 of the weight 24 facing the rear end side in the axis O direction are flush with the surface 22 and the outer peripheral surface 26 facing the rear end side of the tool body 11, respectively. However, this FIG.
In the second embodiment shown in FIG. 4 and FIG. 4, the same parts as those in the first embodiment shown in FIG. 1 and FIG.

However, in such a second embodiment, the surface 3 facing the rear end side of the weight 24 as described above is used.
Since the weight 24 is formed of a material having a higher specific gravity than the tool body 11, despite the fact that the outer surface 2 and the outer surface 25 are flush with the surface 22 and the outer surface 26 facing the rear end side of the tool body. As in the first embodiment, the position of the center of gravity G in the direction of the axis O on the outer peripheral portion 12 of the tool main body 11 can be disposed at substantially the same position as the center of gravity H of the inner peripheral portion 27 or on the rear end side. By preventing the tool main body 11 from being deformed so that the outer peripheral portion 12 bends toward the rear end side during rotation, it is possible to prevent the remaining material from being left uncut. Moreover, by attaching the weight 24 to the recess 31 in this manner,
Weight 24 and the outer peripheral surfaces 25, 2 of the tool body 11
6 can be flush with each other, and the surfaces 22 and 32 facing the rear end side can be flush with each other as described above, so that the tool body 11 can be made more compact and the boss of the tool body 11 can be Even when the protrusion height of the portion 23 is small, it is possible to reliably prevent the weight 24 from interfering with the arbor or the main shaft of the machine tool.

In the first and second embodiments, the weight 24 is removably mounted on the tool body 11, so that the weight 24 is changed according to a change in cutting conditions such as the number of revolutions of the tool body 11. By replacing 24 with a tool having a different weight, it is possible to provide a milling tool that can exert the above-mentioned effects under a wide range of cutting conditions. However, in the case of a rolling tool or the like in which the number of rotations used for cutting is set to a predetermined value in advance, the weight 24 may be integrated with the tool body 11 by, for example, joining the weight 24 thereto. Also, multiple weights with different or equal weights,
They may be used in appropriate combination according to the number of rotations and the like.

Further, in the first and second embodiments,
The weight 24 is formed in an annular shape with the axis O as the center, so that the entire outer periphery of the tool body 11 can be prevented from bending toward the rear end during high-speed rotation of the outer peripheral portion 12. Is playing. However, even when the weight 24 is formed in an annular shape, for example, the weight 2
4 can be divided into a plurality of parts in the circumferential direction, even if one of the divided weights is damaged, etc., it can be replaced only economically. In addition, the weight can be reduced while the tool body 11 is attached to the arbor or the spindle. 24 can be exchanged, and the advantage that workability can be improved can be obtained.

As described above, when the outer peripheral portion 12 of the tool body 11 bends toward the rear end in the direction of the axis O at the time of high-speed rotation, the work material is left uncut and the accuracy of the finished surface is deteriorated. Since only the portion where the cutting edge 18 is provided in the circumferential direction of the tool main body 11 occurs, instead of the annular weight 24 of the first and second embodiments, for example, FIGS. As shown in the third embodiment of the present invention, the outer peripheral portion 12 of the surface 22 facing the rear end side of the tool body 11 is shown.
A plurality of weights 33 may be provided in the circumferential direction of the tool main body 11 so as to be located on the rear end side of the cutting edge 18 in the axis O direction. However, FIG.
Also in the third embodiment shown in FIG.
The same reference numerals are assigned to parts common to the embodiments.

However, also in the third embodiment, the tool body 11 is provided at the portion where the cutting blade 18 is provided.
The position of the center of gravity G of the outer peripheral portion 12 in the direction of the axis O is
7 can be arranged at substantially the same position as the position of the center of gravity H of the tool body 7 or at the rear end side of the tool main body 11 therefrom. By bending to the rear end side of the main body 11, it is possible to prevent the cutting blade 18 from retreating and to leave uncut material on the work material, thereby forming a good finished surface. Further, since the weights 33 are provided at the positions of the cutting blades 18 in this manner, the weight of the entire tool can be reduced as compared with the case where the annular weight 24 is provided. It is particularly effective when used for a milling tool rotated at a high speed.

The shape of the weight 33 is as follows.
Various shapes such as a rectangular parallelepiped block, a flat plate, a pyramid or a cone, or a hemisphere or a column are applicable. Further, even when a weight is provided in the concave portion formed in the tool main body as in the second embodiment, the concave portion is pointed in the circumferential direction of the tool main body so as to be located on the rear end side in the axial direction of the cutting blade. Alternatively, a plurality of weights may be provided in the circumferential direction of the tool main body by providing weights in these recesses.

Further, in the first to third embodiments, the indexable insert 1 on which the cutting edge 18 is formed is provided.
5 is directly attached to the tip mounting seat 14 formed on the tool body 11 by the clamp screw 20. For example, such a throw-away tip 15 is attached to the tool body 11 through a supporter, a sheet, or a wedge member. It may be mounted in the formed mounting groove or the like. In particular, in this case, the mounting groove is formed so as to open in the surface 22 facing the rear end side of the tool body 11 or the concave portion 31 so that the rear end of the supporter or the sheet contacts the weights 24 and 33. If these are set, for example, these weights 24,
By forming 33 from a material having high rigidity such as a steel material, it is possible to improve the mounting rigidity of the throw-away tip 15.

[0025]

As described above, according to the present invention,
In order to increase the cutting speed to achieve efficient cutting, or when cutting aluminum materials, etc., even when rotating the tool body at high speed, the tool body with the cutting edge provided in the axial direction of the tool body The position of the center of gravity in the outer peripheral portion can be located at approximately the same position or the rear end side with respect to the inner peripheral portion side, and there is no cutting left on the work material due to deformation generated in the tool body due to centrifugal force due to high speed rotation. Such a situation can be prevented, and the accuracy of the finished surface of the work material can be improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a sectional view of the first embodiment shown in FIG.

FIG. 3 is a side view showing a second embodiment of the present invention.

FIG. 4 is a sectional view of the second embodiment shown in FIG.

FIG. 5 is a side view showing a third embodiment of the present invention.

FIG. 6 is a sectional view of the third embodiment shown in FIG.

FIG. 7 is a side view showing a conventional milling tool (front milling tool).

8 is a view showing deformation of the tool main body 1 when the milling tool shown in FIG. 7 is rotated at a high speed.

[Explanation of symbols]

 Reference Signs List 11 tool main body 12 outer peripheral portion of tool main body 11 15 throw-away tip 18 cutting edge 22 surface facing rear end side of tool main body 11 24, 33 weight 27 inner peripheral portion of tool main body 11 31 recess O axis of tool main body 11

Claims (6)

[Claims] 1. A milling tool comprising a substantially disk-shaped tool body rotated around an axis and having a cutting edge provided at an outer peripheral portion of a tip end thereof, wherein a cutting edge is provided on an outer peripheral portion of a surface facing a rear end side of the tool body. A milling tool characterized in that a weight is provided. 2. The milling tool according to claim 1, wherein the weight is provided so as to project toward the rear end in the axial direction from a surface facing the rear end of the tool body. . 3. A concave portion is formed on an outer peripheral portion of a surface facing a rear end side of the tool main body, and the weight is formed of a material having a specific gravity greater than that of the tool main body and is disposed in the concave portion. The milling tool according to claim 1, wherein the cutting tool is formed. 4. The device according to claim 1, wherein the weight is provided on a surface facing the rear end of the tool body in an annular shape about the axis. Milling tools. 5. The weight is provided scattered in a circumferential direction of the tool main body so as to be located on a rear end side in an axial direction of the cutting blade in a surface facing a rear end side of the tool main body. The milling tool according to any one of claims 1 to 3, wherein: 6. The milling tool according to claim 1, wherein the weight is detachably attached to the tool body.