JPS6317604Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a carbide drill in which a cutting blade tip made of cemented carbide having a cutting blade is provided at the tip of the drill body, and more specifically, the inner edge of the two cutting blades is This invention relates to a carbide drill installed at a distance of 0.1 mm to 1.25 mm from the rotation center axis.

Generally, in this type of carbide drill, the cutting edge is made of cemented carbide, and the inner edge of the cutting edge is spaced apart from the rotation center axis of the drill to reduce the thrust load. Because of this, it is possible to perform high-speed, high-feed drilling.
This provides the advantage of improving the efficiency of drilling.

However, when high-speed, high-feed drilling is performed, a large amount of chips are generated. For this reason, a new problem has arisen in that there is a risk of chip clogging, especially when drilling deep holes.

This idea was made in consideration of the above circumstances, and even when performing high-speed, high-feed drilling,
To provide a carbide drill capable of smoothly discharging chips to the outside of a hole without causing chip clogging.

The feature of this device is that a groove having a wall surface with a radius of curvature smaller than the radius of curvature of the wall surface of that part is formed along the chip discharge groove at least at the tip of the bottom wall surface of the chip discharge groove, and the groove is formed from the tip side. This point is formed by extending toward the rear end of the outer edge of the cutting edge than the imaginary line perpendicular to the outer edge.

An embodiment of this invention will be described below with reference to FIG. Note that FIG. 1A is an axial tip end view of the carbide drill according to this invention, and FIG. 1B is a side view thereof. In the figure, reference numeral 1 indicates a drill body made of steel. Chip discharge grooves 2, 2 extending along the rotation center axis O are provided on the outer periphery of the tip of the drill body 1. A cutting blade tip 3 made of cemented carbide is fixed by brazing to the wall surface of each chip discharge groove 2 facing the direction of rotation. This cutting blade tip 3
A cutting edge 4 is formed at the tip. The two cutting blades 4 are arranged point-symmetrically with respect to the rotation center axis O, and each inner edge 4a is oriented from the rotation center axis O.
They are placed 0.1mm to 1.25mm apart.

The above configuration is the same as that of a conventional carbide drill, but furthermore, in the carbide drill according to this invention, there is a groove extending along the chip discharge groove 2 at the tip of the bottom wall surface of the chip discharge groove 2. A groove 5 is formed. This groove 5 is for forcibly curling and dividing the chips generated by the cutting blade 4. Therefore, the wall surface of the groove 5 is
The radius of curvature is set smaller than the radius of curvature of the wall surface where the Further, the groove 5 is formed in the drill body 1.
It extends from the tip side to the rear end side of the imaginary line L perpendicular to the cutting blade tip 3 at the outer edge 4b of the cutting blade tip 3.

Therefore, when drilling is performed using the carbide drill configured as described above, the chips generated by the cutting edge 4 are forcibly curled and divided by the groove 5. That is, chips generated by the cutting tip 3 are generated in a direction perpendicular to the cutting tip 3, but when the groove 5 is formed from the tip side of the drill body 2 to the outer edge 4b of the cutting tip 3, Since the cutting blade tip 3 is formed to extend toward the rear end side of the imaginary line L perpendicular to the cutting edge tip 3, the entire width of the chip in the width direction collides with the groove 6. In particular, since the thicker part of the chips generated on the outer edge 4b side of the cutting edge 3 also collides with the wall of the groove 6, the chips can be curled and separated reliably and effectively, unlike the conventional method. be able to. Moreover, since the groove 5 is formed along the chip discharge groove 2, the separated chips are removed from the groove 5.
There is a smooth transition from to the chip discharge groove 2. Therefore, even if high-speed, high-feed drilling is performed, chips can be smoothly discharged to the outside of the hole without clogging.

Note that in order to curl and divide the chips, it is possible to reduce the radius of curvature of the wall surface of the chip discharge groove 2 itself, but if this is done, the cross-sectional area of the chip discharge groove 2 will become narrower, and even if the chips are curled Even if it were possible to separate it, it would be difficult to discharge it smoothly, so it cannot be called a fundamental solution.

Moreover, FIG. 2 shows another embodiment of this invention. This embodiment differs from the above embodiments in that the groove 5 is formed over the entire direction in which the chip discharge groove 2 extends. Since the other configurations are the same as those of the above embodiment, the same parts are given the same reference numerals and the explanation thereof will be omitted. In this case, since the groove 5 is formed over the entire chip discharge groove 2, chips can be discharged more smoothly than in the above embodiment in which the groove 5 is formed only at the tip of the chip discharge groove 2. be able to.

As explained above, according to the carbide drill of this invention, a groove having a wall surface with a radius of curvature smaller than the radius of curvature of the wall surface of that portion is formed at least at the tip of the bottom wall surface of the chip discharge groove. , the chips generated by the cutting blade can be finely curled and divided, and the groove can be extended from the tip side to the rear end side of the outer edge of the cutting blade tip beyond an imaginary line perpendicular to this. Because of this structure, the entire width of the chip collides with this groove, making it possible to reliably and effectively break up the chips, and the separated chips smoothly move from the groove to the chip discharge groove. .
Therefore, clogging with chips can be prevented even in high-speed, high-feed drilling where the thickness is large and a large amount of chips are generated. In addition, since chip clogging can be prevented, deeper holes can be drilled, and the walls of the drilled hole are not damaged by abrasion due to chips, improving the accuracy of the hole. Effects such as being able to do this can be obtained.

[Brief explanation of the drawing]

The attached FIGS. 1 and 2 each show an embodiment of this invention, with A being a front end view in the axial direction, and B being a partially omitted side view thereof. 1... Drill body, 2... Chip discharge groove, 3...
Cutting blade tip, 4... Cutting blade, 4a... Inner edge, 4b
...outer edge, 5...groove, L...extension line, O...rotation center axis.

Claims (1)

[Scope of utility model registration request] A chip discharge groove is provided on the outer periphery of the tip of the drill body.
A cutting tip made of cemented carbide is provided at the tip of the wall surface facing the rotational direction of this chip discharge groove, and each inner edge is 0.1 mm or more from the rotational center axis of the drill body at the tip of the cutting tip. In a carbide drill having two cutting edges 1.25 mm apart and formed approximately point symmetrically, a groove having a wall surface with a radius of curvature smaller than the radius of curvature of the wall surface of that portion is formed on the wall surface of the bottom portion of the chip discharge groove. The groove is formed along a chip discharge groove, and the groove extends from the tip of the chip discharge groove to the rear end side of an imaginary line perpendicular to the cutting tip at the outer edge of the cutting tip. Carbide drill.