JPH039935Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a throw-away milling tool in which a plurality of throw-away tips are attached to the outer periphery of the tip of a tool body along the axial direction of the tool body.

[Prior Art] In recent years, throw-away type milling tools have become popular as milling tools used in end mills, etc., in which a plurality of throw-away tips are detachably attached to the outer periphery of the tip of the tool body along the axial direction. It is becoming widely used.

FIGS. 9 to 14 show a conventional throw-away milling tool of this type (hereinafter abbreviated as "milling tool").
The reference numeral 1 in the figure indicates the tool body of this milling tool.

The tool body 1 has a substantially cylindrical shape with its base end rotatably held around an axis by a drive source such as an end mill, and at positions equally spaced in the circumferential direction on the outer periphery of its distal end. A threaded tip pocket 2 with multiple threads (four threads in the figure) opening on the outer circumferential side and the tip side.
...is formed. Further, on the outer peripheral surface of the tool body 1, a plurality of (four in the figure) chip mounting seats 3 are formed along each chip pocket 2 and facing the chip pocket 2. Throwaway chips (hereinafter abbreviated as chips) 4 are mounted on these chip mounting seats 3, respectively.

As shown in FIGS. 12 to 14, the chip 4 has a substantially rhombic plate shape, and main cutting edges 7 are formed on four ridges 6 on the upper surface 5, respectively. Rake faces 9 are formed on the side surfaces from the main cutting edges 7 to the lower surface 8 which serves as a seating surface. Here, each rake face 9 is a rake face 9 at the cutting edge center 10 of the main cutting edge 7,
The width dimension between 9 and 9 is the cutting edge both ends 11 and 1 of the main cutting edge 7.
It is formed of a smooth convex curved surface that is larger than each width dimension in 2 and 2.

As shown in FIGS. 9 to 11, each of the chips 4 has its upper surface 5 located on the outer peripheral surface side of the tool body 1, and each of the main cutting edges 7... It is connected in the axial direction of the tool body 1 and detachably attached to the tip mounting seat 3 of the tool body 1. Here, in these chips 4, the tip of the cutting edge 11 forming an acute angle is the cutting edge tip, and the tip of the cutting edge 12 forming an obtuse angle is the tip of the cutting edge of the tool body 1. They are arranged alternately in the circumferential direction, and all the chips 4 are mounted with equal positive axial rake angles α.

Therefore, in the conventional milling tool described above, the chips 4 have two types: one with the acute-angled cutting edge 11 as the cutting edge tip, and the other with the obtuse-angled cutting edge 12 as the cutting edge tip. Since they are arranged alternately along the circumferential direction of the tool body 1, all four main cutting edges 7 can be used interchangeably. It is also known that since the rake face 9 is formed on the side surface of the chip 4 in a convexly curved shape, the cutting edge angle β becomes larger and the strength of the cutting edge is improved, and even better chip evacuation performance can be obtained. It is being

[Problems to be solved by the invention] However, in the conventional milling tool described above, since all the chips 4 are attached with a positive axial rake angle α, the tooling due to each chip 4 All of the chip force in the axial direction of the tool body 1 acts toward the tip side of the tool body 1. For this reason, when performing heavy cutting such as cutting with a large feed rate by taking advantage of the high strength of the cutting edge of the tips 4, the sum of the component forces in the axial direction acting on the tool body 1 increases, and the entire tool is There is a fear that this may cause chatter, vibration, etc., and improvements have been desired.

[Purpose of the invention] This invention was made in view of the above circumstances.
In addition to the advantages obtained from the convexly curved rake face of the installed chip, this milling tool also reliably prevents the occurrence of cracks and vibrations caused by forces acting in the axial direction of the tool body. The purpose is to provide the following.

[Means for Solving the Problems] The milling tool of this invention has a cutting edge formed on the side surface extending from the main cutting edge formed at the ridgeline portion of the upper surface to the lower surface serving as the seating surface, and between these side surfaces at the center of the main cutting edge. A plurality of polygonal plate-shaped chips each having a convex curved rake face whose width dimension is larger than each width dimension at both ends of the cutting edge of the main cutting edge are formed on the outer periphery of the tip of the tool body. The one facing the tip pocket of the one with a positive axial rake angle,
It is installed so that the difference between the positive axial rake angle and the negative axial rake angle having the same absolute value is 1 or less.

[Example] Figures 1 to 3 show a first embodiment of the milling tool of this invention, and parts common to those shown in Figures 9 to 14 are given the same reference numerals. The explanation will be omitted.

1 to 3, in the milling tool of this example, chips 4a, 4b, etc., which have the same shape as the above-mentioned conventional one, are mounted on the chip mounting seats 3, etc. of the tool body 1, respectively.
They are detachably attached to each other in a positional relationship different from conventional ones.

That is, in the milling tool of this example, the tool body 1
Along each tip pocket 2, which extends in the axial direction of The throw-away tips 4b and the throw-away tips 4b are alternately attached.

Therefore, in the case of such a milling tool, the chips 4a..., 4b... along the same chip pocket 2 are
Since the axial rake angles α and α are the same angle and the positive and negative sides are reversed, these chips 4a
..., 4b... acting in the axial direction of the tool body 1 can be canceled out from each other. Therefore, no force in the axial direction due to the cutting force acts on the tool body 1. Therefore, according to this milling tool, the installed chip 4a
In addition to the above-mentioned various advantages obtained by the convex curved rake faces 9 of ..., 4b..., even when used for heavy cutting, the force acting on the tool body 1 in the axial direction can be reduced. There is no risk of chatter or vibration occurring due to this.

[Other Embodiments] FIGS. 4 to 6 show a second embodiment of the milling tool of this invention.

In the milling tool of this example, four linear tip pockets 20 are formed on the outer periphery of the tip of the tool body 1 at equal intervals in the circumferential direction. Also in the milling tool of this example, along each chip pocket 20, the throwaway chip 4a is provided with a positive axial rake angle α;
Throwaway tips 4b having negative axial rake angles α having the same absolute value as this positive axial rake angle α are alternately mounted.

Therefore, with the milling tool of this example, it is possible to obtain the same effects as those shown in the first example above, and in addition, it is possible to obtain the same effects as those shown in the first example above, and in addition, it is possible to obtain the same effect as that shown in the first example above. Even when only one row of chips 4a, 4b along the chip pocket 20 is involved in cutting, the cutting forces in the axial direction are canceled out between these rows of chips 4a, 4b, resulting in stable cutting. If you can do it, you can also get the same effect.

In the above embodiments, chips 4, 4a, and 4b each have a diamond-shaped external appearance, but the present invention is not limited to this, and a convex curved rake face similar to that of the chip 4 may be formed on the side surface. A chip 22 having a substantially square shape in appearance as shown in FIG. 7, a chip 23 having a substantially triangular shape in appearance as shown in FIG. 8, etc. may be attached.

Further, in the above embodiment, both chips 4a and 4b have opposite positive and negative axial rake angles α.
are attached alternately along the tip pockets 2 and 20, but the invention is not limited to this. The axial rake angle α of the tips located at the most distal and proximal ends of the tool body 1 is assumed to be positive, and the axial rake angle α of the tips located at the most distal and proximal ends of the tool body 1 is set as positive, do 2
The axial rake angle α of each chip may be set to be negative. In other words, the point is that half of the tips 4 along the tip pockets 2, 20 should be attached so that the axial rake angle is positive, and the other half should be attached so that the axial rake angle is negative. Therefore, the difference between the positive and negative axial rake angles of chips along the same chip pocket is 0 if the total number of chips along this chip pocket is an even number, and 1 if the total number of chips is an odd number. You just have to wear it as you see fit.

[Effect of the invention] As explained above, the milling tool of this invention has a width dimension between the side surfaces from the main cutting edge to the lower surface at the center of the main cutting edge that is wider than both ends of the cutting edge of the main cutting edge. A plurality of polygonal plate-shaped chips each having an increasing convex curved rake face are placed facing the same chip pocket in the tool body, and one has a positive axial rake angle, and the other has a positive axial rake angle. It is installed so that the difference between the angle and the one with a negative axial rake angle with the same absolute value is 1 or less. Therefore, according to this milling tool, in addition to the various advantages obtained by the convex curved rake face of the mounted chips, the cutting tool also has the advantage that the cutting tool acts in the axial direction of the tool body of the chips facing the same chip pocket. Since the cutting forces cancel each other out, even when used for heavy cutting,
There is no risk of chatter or vibration occurring due to the force acting on the tool body in its axial direction.

[Brief explanation of the drawing]

1 to 3 and 4 to 6 respectively show the first and second embodiments of the indexable milling tool of this invention.
The figures are each a developed view of the tool body with the chip attached, Figures 2 and 5 are cross-sectional front views of the main parts showing the rotation locus of the attached chip, and Figures 3 and 6 are respectively Bottom view of the above milling tool, No. 7
Figures 9 and 8 show other embodiments of this invention, respectively, and are developed views of the tool body with the chip attached, and Figures 9 to 14 show conventional throw-away milling tools. Fig. 9 is a cross-sectional front view of the main part showing the rotation locus of the installed chip, Fig. 10 is a bottom view of the milling tool, and Fig. 11 is a developed view of the tool body with the chip installed. , FIG. 12 is a front view showing the chip attached to the milling tool, FIG. 13 is a view taken along the line P ₁ -P ₁ in FIG. 12, and FIG. 14 is a view taken along the line P ₂ -P ₂ in FIG. It is a line view. 1... Tool body, 3... Chip mounting seat, 2, 2
0...Tip pocket, 4, 4a, 4b...Throwaway tip, 5...Top surface, 6...Ridge part,
7...Main cutting edge, 8...Bottom surface, 9...Rake face, 1
0...Center of cutting blade, 11, 12...Edge of cutting blade, β...
...Blade angle, α...Axial rake angle.

Claims (1)

[Claims for Utility Model Registration] A tip pocket is formed along the axial direction on the outer periphery of the tip of the tool body, and a plurality of polygonal plate-shaped throw-away tips are arranged along the tip pocket, and the top surface of the tip pocket is attached to the tip of the tool body. The main cutting edges are located on the outer circumferential surface side and are attached so that the main cutting edges formed on the ridgeline portions of the upper surfaces thereof are continuous in the axial direction of the tool body in their rotation locus,
And the throw-away tip has a side surface from the main cutting edge to the lower surface serving as the seating surface, and a width dimension between these side surfaces at the center of the main cutting edge is larger than each width dimension at both ends of the cutting edge of the main cutting edge. In an indexable milling tool having a convex curved rake face, in the same chip pocket, a throwaway tip with a positive axial rake angle has the same absolute value as the positive axial rake angle. A throw-away milling tool characterized in that a throw-away tip with a negative axial rake angle is mounted so that the difference in number between the chips is 1 or less.