JP2515006Y2 - End mill with corrugated peripheral blade on cylindrical surface - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is an improvement of an end mill in which a plurality of outer peripheral blades are spirally twisted on one cylindrical surface, form a substantially sinusoidal waveform, and the waveforms are out of phase with each other. It is about.

[0002]

2. Description of the Related Art (a) A plurality of outer peripheral blades that are spirally twisted on one cylindrical surface and that are provided with irregularities on the rake face along the spiral form a substantially sinusoidal waveform. There is known an end mill including a blade portion formed in a state where waveform phases are shifted from each other, and (b) a shank integrally provided coaxially with the blade portion.
JP-B-47-10316 and JP-A-62-6821
The end mill described in Japanese Patent Publication No. 7 is an example thereof, and according to such an end mill, the axial rakes of the outer peripheral blades are continuously changed and the phases of the waveforms are deviated from each other, which causes chatter vibration. Is suppressed, heavy cutting and high-efficiency machining are possible, and excellent finished surface roughness is obtained.

[0003]

However, when the corrugations of the plurality of outer peripheral blades are out of phase with each other as described above, the outer peripheral blade in which the corrugated concave portion is located in the round-up portion of the blade portion near the shank is However, the cross-sectional area perpendicular to the axis is reduced, stress concentration is likely to occur, and the breakage strength of the end mill is reduced. Since such an end mill is usually used for heavy cutting or high-efficiency processing as described above,
Decrease in breakage strength is a serious problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to break an end mill having a plurality of corrugated outer peripheral blades on one cylindrical surface and the corrugations of the corrugations being out of phase with each other. It is to improve the strength.

[0005]

In order to achieve the above object, the present invention provides: (a) spirally twisting on one cylindrical surface, and the rake surface is provided with irregularities along the spiral. A blade portion in which a plurality of outer peripheral blades having a substantially sinusoidal waveform are formed with their waveform phases shifted from each other, and (b) a shank integrally provided coaxially with the blade portion. In an end mill having
(C) The outer peripheral blade is characterized in that the raised portion near the shank has a parallel portion formed continuously from the corrugated convex portion and substantially parallel to the spiral.

[0006]

In this end mill, since the outer peripheral blade has a rounded-up portion near the shank, a parallel portion is provided substantially parallel to the spiral from the wavy convex portion.
Compared to a conventional end mill in which a corrugated concave portion is located in the raised portion, there is an outer peripheral blade, and the cross-sectional area perpendicular to the axial center of the raised portion is increased, stress concentration is reduced, and the break strength of the end mill is improved. . As a result, while maintaining the effect of improving the cutting performance and the finished surface roughness by the corrugated outer peripheral blade, the tool life is extended and further heavy cutting and high efficiency machining are possible.

The length dimension of the parallel portion substantially parallel to the spiral differs depending on the phase of the waveform of each outer peripheral blade, but in order to prevent the cutting performance from deteriorating, even the longest one has a waveform pitch of 1.5. It is desirable to set it within twice.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view of an end mill 10 (hereinafter, simply referred to as end mill 10) having a corrugated outer peripheral blade on a cylindrical surface, which is one embodiment of the present invention, as viewed from a direction perpendicular to an axis, and FIG. 11 is a sectional view taken along line II-II of FIG. The end mill 10 is provided with a shank 12 and a blade portion 14 which are gripped by a milling machine and the like coaxially and integrally, and the blade portion 14 has four
By providing four twist grooves, four outer peripheral blades 16
A, 16b, 16c, 16d (hereinafter, simply referred to as outer peripheral blade 16 unless otherwise specified) are formed. These outer peripheral blades 16 have the same shape and are equally divided in the circumferential direction, that is, they are provided at 90 ° intervals.

The outer peripheral blade 16 is helically twisted at a constant twist angle on one cylindrical surface having a constant diameter and has a corrugated shape. This corrugation is formed by providing smooth irregularities on the rake face along the spiral, and each outer peripheral blade 16 has a constant corrugation height H and pitch P, as is apparent from the development view of FIG. The convex portions 18 and the concave portions 20 are alternately and continuously formed in a substantially sinusoidal shape, and the four outer peripheral blades 16 are such that the waveform phases thereof are adjacent to each other in the direction opposite to the cutting rotation direction. P / 4
Each is shifted toward the tip side in the axial direction. In addition, these outer peripheral blades 16 are continuously formed substantially parallel to the spiral from the top of the convex portion 18 at the portion located at the raised portion 22 near the shank 12 and at the tip side portion of the end mill 10. The parallel portions 24 and 26 are provided. The length dimension of the parallel part 24 differs depending on each outer peripheral blade 16 as in the parallel part 26 shown in FIG. 3, but the longest one is the corrugated pitch P.
0.75 to 1.5 times the range, preferably 1 to 1.
It is set to be within a range of 5 times, and in the vicinity of the shank 12 shown in the sectional view of FIG. 2, all are parallel portions 24, and each outer peripheral blade 16 has the same cross section as the corrugated convex portion 18. Is done.

The end mill 10 configured as described above
When the shank 12 is gripped by a milling machine or the like (not shown) and is driven to rotate about the axis, the four outer peripheral blades 16 cut the work material (not shown). In that case, the outer peripheral blade 16 of the end mill 10 has a corrugated waveform in the circumferential direction, and the axial rake of the outer peripheral blade 16 is continuously changing, and the phases of the waveforms are shifted from each other. , Chatter vibration is suppressed, cutting performance is improved, and heavy cutting and high efficiency cutting are possible. Further, since the outer peripheral blade 16 is formed on one cylindrical surface, excellent finishing surface roughness can be obtained due to the effect of improving cutting performance.

On the other hand, in the end mill 10 of this embodiment, since the outer peripheral blades 16 of the cut-up portion 22 are provided with the parallel portions 24 continuous from the top of the convex portion 18, as shown in FIG. 5 and FIG. As compared with the conventional end mill 30 in which the blade 32 is not provided with the parallel portion 24, the cross-sectional area of the cut-up portion 22 perpendicular to the axis is increased, stress concentration is reduced, and high breakage strength is obtained. This allows
While maintaining the effect of improving the cutting performance and the finished surface roughness by the corrugated outer peripheral blade 16, the tool life is extended and further heavy cutting and high efficiency machining are possible. In the above-mentioned conventional end mill 30, as is clear from FIG. 6 showing the cross section at the cut-up portion, the cross-sectional shape of each outer peripheral blade 32 differs depending on the phase of the corrugation, and the outer peripheral blade 32a has the corrugated concave position and the outer peripheral blade 32b. Is the intermediate position between the concave portion and the convex portion, the outer peripheral blade 32c is the convex portion position, and the outer peripheral blade 32d is the intermediate position between the convex portion and the concave portion.

Incidentally, the blade diameter is 20 mm and the blade length is 45 m.
m, shank diameter 20 mm, corrugated pitch P = 9.5 m
m, the height of the corrugation H = 1.2 mm, the twist angle of the outer peripheral blade is 3
0 °, 4 blades, 8% Co HSS (HRC6
Two pieces of each of the present invention product and the conventional product of 8) were prepared, and a cutting test was conducted under the following cutting conditions. The results shown in FIG. 4 were obtained. In the product of the present invention, the maximum length of the parallel portion 24 is 12 mm (about 1.25 times the pitch P of the waveform).

(Cutting conditions) Work material: S50C (HRB92) Cutting speed: 475 rpm Feed: 150 mm / min down cut Depth of cut: 30 mm x 10 mm Cutting oil: Sulfur chloride-based water-insoluble cutting oil・ Machine: Vertical machining center

As is apparent from FIG. 4, there is almost no difference between the conventional product and the product of the present invention in the degree of increase in the flank wear width of the outer peripheral blade due to cutting, but the conventional product escapes after cutting about 13 m. Two pieces were broken together when the surface wear width was about 0.35 mm, whereas the flank wear width was 0.45 to 0.50 mm when the product of the present invention was cut by 17 m (130% or more of the conventional product). It did not break even when it became (130% or more of the conventional product). From this, it is understood that the present invention greatly improves the breakage strength.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be embodied in other forms.

For example, the number of outer peripheral blades 16, the pitch P of the corrugations, the height H, the lengths of the parallel portions 24, 26, etc. can be set appropriately, and a plurality of outer peripheral blades 16 are provided at unequal intervals around the axis. It is also possible.

Further, in FIG. 3, it is possible to reverse the phase shift direction of the outer peripheral blade 16 or change the order of the outer peripheral blades 16a to 16d in the peripheral direction. Each peripheral blade 1
The phase shift amount of 6 does not necessarily have to be strictly P / 4, and the phase shift amounts of the four outer peripheral blades 16 do not have to be the same.

Further, a taper end mill in which an outer peripheral blade is located on a tapered cylindrical surface whose diameter continuously changes in the uniaxial direction, and a nick for cutting chips on the flank surface The present invention can be similarly applied to formed end mills and the like.

Although not specifically exemplified, the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a front view of an end mill having a corrugated outer peripheral blade on a cylindrical surface, which is an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a development view showing an outer peripheral blade of the end mill shown in FIG. 1.

FIG. 4 is a diagram for explaining test results of a cutting test performed using two of the present invention product and two of the conventional product.

FIG. 5 is a front view showing an example of a conventional end mill.

6 is a sectional view taken along line VI-VI in FIG.

[Explanation of symbols]

 10: End mill equipped with corrugated outer peripheral blade on cylindrical surface 12: Shank 14: Blade portion 16a, 16b, 16c, 16d: Outer peripheral blade 18: Convex portion 22: Rounded portion 24: Parallel portion

Claims (1)

(57) [Scope of utility model registration request] 1. A plurality of outer peripheral blades which are twisted in a spiral shape on one cylindrical surface and are provided with irregularities on a rake surface along the spiral to form a substantially sinusoidal waveform, and the outer peripheral blades are corrugated with each other. In an end mill having a blade portion formed in a phase-shifted state and a shank integrally provided coaxially with the blade portion, the outer peripheral blade has a corrugated convex portion at a round-up portion near the shank. End mill having a corrugated outer peripheral blade on a cylindrical surface, characterized in that it has a parallel portion formed continuously from the above to substantially parallel to the spiral.