JPH0344412Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field This invention relates to a hole cutter.

Purpose The purpose of this invention is to provide a new hole cutter that not only makes it easy to polish the inner and outer cutters, but also discharges chips in a powdered form to increase cutting efficiency. It's about doing.

Structure of the Device In order to achieve the above object, in this device, a plurality of cutting blades are provided on the lower edge of the cylindrical cutter body, and a chip discharge groove is provided on the outer periphery of the cutter body corresponding to each cutting blade. In the formed hole cutter, the radial rake of the blade surface in the rotational direction of the cutting blade is set to 0 degrees, and the blade width is made approximately the same.
The apex of the outer cutter is formed at a position closer to the outer side of the blade width so that the apex of the outer cutter and the apex of the inner cutter have different rotation trajectories, and the apex of the inner cutter is formed at a position closer to the inner side of the blade width. At the same time, the apex of the inner blade is placed approximately in the center of the cutting width of the inner blade so that the width of the outer cutting edge and the width of the inner cutting edge involved in cutting of the inner blade are almost the same. Furthermore, the inclination angles of the outer cutting edge portion and the inner cutting edge portion of both the inner and outer blades with respect to the cutting surface are set to be approximately the same, and the lower edge of the cutting discharge groove is sloped from the lower inner side to the upper outer side. This hole cutter is characterized by having an inclined guide surface formed thereon.

Embodiment Hereinafter, an embodiment embodying this invention will be described with reference to the drawings. The cutter body 2 of the hole cutter 1, which is rotated in the direction of the arrow in FIG. 2, is formed in a cylindrical shape, and is attached to the shank of a drill by a mounting portion 3 protruding from its upper end. Six oblique chip discharge grooves 4 are formed on the outer peripheral surface of the cutter body 2 at irregular or equal intervals.

Between each of the chip discharge grooves 4, the lower edge of the cutter body 2 is integrally formed with an outer cutter 5, in which the apex A of the cutting edge is located on the outside, and an inner cutter 6, in which the apex B of the cutting edge is located inside. ing. And each blade 5,
The radial rake of No. 6 is set to 0 degrees. As shown in FIG. 3, the apex A of the outer cutter 5 is provided at a position approximately one-fourth of the blade width W from the outer surface, and the inclination angle θ1 from the apex A is 15 degrees with respect to the cutting surface F.
An outer cutting edge portion 5a having an angle of inclination θ2 of 25 degrees is formed facing outward, and an inner cutting edge portion 5b having an inclination angle θ2 of 25 degrees is formed facing inside. Also, the apex B of the inner cutter 6 is approximately the width W of the blade from its outer surface.
The outer cutting edge portion 6a and the inner cutting edge portion 6b, which are provided at a seven-tenth position and have inclination angles θ3 and θ4 of 15 degrees and 25 degrees, respectively, from the apex B to the cutting surface F are outward and outward. Formed inwardly.

On the other hand, a height difference is provided between the apexes A and B of the outer cutter 5 and the inner cutter 6, and the apex B of the inner cutter 6 is placed at the center of the cutting width S. The apex A of the blade 5 is provided at a higher position.
At the lower end of the chip discharge groove 4, there is formed an inclined guide surface 8 for guiding chips, which is inclined from the inner part of the lower part to the outer part of the upper part and is continuous with the chip discharge groove 4.

Now, if the hole cutter 1 configured as described above is used, the rotation loci of the vertices A and B of each blade 5 and 6 will be different, and the position of the apex A of the outer blade 5 will be changed from the position of the apex of the inner blade 6. Raise it higher than position B and insert the inner blade 6.
By arranging the apex B at the center of the cutting width S, the respective cutting amounts by the inner and outer cutting edges 6a and 6b are made uniform, cutting efficiency is stabilized, and the chips are transferred to the apex B. Since it can be pulverized by merging at the same position, it is possible to make the chips generated during drilling and cutting into smaller pieces. Furthermore, in this embodiment, the radial rake is 0 degrees, that is, as shown in FIG.
Since the hole cutter 1 does not form any positive or negative inclination angle on the plane perpendicular to the axis of the hole cutter 1, and is set to coincide with the line L in the radial direction, the flow of chips is directed outside the circumference. The chips are guided directly upward without being pushed in the direction or in the circumferential direction, and since the inclined guide surface 8 is formed on the lower edge of the chip discharge groove 4 corresponding to each of the chips 5 and 6, The chips cut by the inner cutter 6 collide with the inclined guide surface 8 and are chip-broken, and the chips are further broken down and easily discharged outward from the chip discharge groove 4. Therefore, the cutting efficiency can be increased and it is suitable for unmanned operation.

In addition, in this embodiment, the inclination angles θ1 and θ3 of the outer cutting edge portions 5a and 6a of each blade 5 and 6 with respect to the cutting surface F are uniformly set to 15 degrees, and the inclination angles of the inner cutting edge portions 5b and 6b are uniformly set to 15 degrees. Since the angles θ2 and θ4 are set uniformly at 25 degrees, both the inner and outer flanks 9 of each blade 5, 6
The polishing work of a, 9b, 10a, and 10b can be performed extremely easily.

Effects of the device As detailed above, this device has the same angle of inclination of the outer cutting edge and the inclination angle of the inner cutting edge with respect to the cutting surface of both the inner and outer cutters. Not only can polishing be easily performed, but also because the rotation locus of the apex of each blade is different and the apex of the inner blade is located approximately in the center of its cutting width, the inner and outer cutting edges of the inner blade are The cutting efficiency can be made uniform and chips can be finely pulverized by joining them at the top of the inner cutter, and by setting the radial rake to 0 degrees, the flow of chips is directed directly above the inclined guide surface. Since chip breaking can be performed by colliding with the inclined guide surface, the chips can be discharged in a finer state, resulting in an excellent effect of increasing cutting efficiency.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of this invention, FIG. 2 is a bottom view, and FIG. 3 is a partial sectional view. Cutter body...2, Chip discharge groove...4, Outer blade...5, Inner cutter...6, Cutting blade...5a, 5b, 6
a, 6b, apex...A, B, cutting surface...F, cutting width...S, blade width...W, inclination angle...θ1 to θ4.

Claims (1)

[Claims for Utility Model Registration] 1. A plurality of cutting blades 5, 6 are provided on the lower edge of the cylindrical cutter body 2, and a chip discharge groove is provided on the outer periphery of the cutter body 2 corresponding to each cutting blade 5, 6. In the hole cutter 4, the radial rake of the blade surface in the rotational direction of the cutting blades 5 and 6 is set to 0 degrees, and the outer blade 5 and the inner blade 6 have approximately the same blade width W. The apex A of the outer cutter 5 is formed at a position closer to the outer surface of the blade width W so that the apex A of the outer cutter 5 and the apex B of the inner cutter 6 have different rotation trajectories, and the inner cutter The apex B of the inner cutter 6 is formed at a position closer to the inner surface of the blade width W, and the apex B of the inner cutter 6 is formed by the width of the outer cutting edge portion 6a and the width of the inner cutting edge portion 6b that are involved in cutting the inner cutter 6. The outer cutting edge portions 5a and 6 of the inner and outer blades 5 and 6 are arranged approximately at the center of the cutting width S of the inner cutter 6 so that they are almost the same.
The inclination angles θ1, θ3, θ2, and θ4 of the inner cutting edges 5b and 6b with respect to the cutting surface F are set to be almost the same, and the lower edge of the cutting discharge groove 4 is provided with grooves extending from the inner part of the lower part to the outer part of the upper part. Slanted guide surface 8 that slopes toward the direction
A hole cutter characterized by forming a. 2 Inclination angle θ1 of the outer cutting edge portions 5a, 6a,
The hole cutter according to claim 1, wherein θ3 is 15 degrees, and the inclination angles θ2 and θ4 of the inner cutting edges 5b and 6b are 25 degrees. 3. The hole cutter according to claim 1 or 2 of the utility model registration claim, characterized in that a height difference of a predetermined interval is provided between the vertices A and B of the outer cutter 5 and the inner cutter 6.