JPS6122731Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a throw-away drill that can simultaneously perform drilling and chamfering or counterboring the hole created by the drilling.

For example, when drilling a screw hole, the drilling process and the chamfering of the hole created by the drilling process are performed simultaneously, thereby improving the processing efficiency.

By the way, as shown in FIGS. 1 and 2, a conventional throw-away drill used for this type of drilling has a tip 2 at the tip of a tool body 1 for drilling. Furthermore, an outer circumferential cutting tip 4 for chamfering is attached to the outer periphery of the drill body 11 at a distance approximately equal to the thickness of the workpiece 3 from the distal cutting tip 2.

However, in such a conventional drill, since both the distal cutting edge tip 2 and the peripheral cutting edge tip 4 are located on one parallel plane along the drill axis, the distal cutting edge tip 2 When the generated chips are discharged to the outside through the chip discharge groove 5, the peripheral cutting edge tip 4 is damaged by abrasion due to the chips, which shortens the life of the peripheral cutting edge tip 4. Smooth discharge of chips is obstructed by the outer cutting edge tip 4, and chip clogging occurs.
As a result, there was a drawback that the drill body 1 was damaged.

This idea was made in view of the above circumstances,
To prevent the outer cutting edge tip from being damaged by abrasion caused by chips by arranging the outer cutting edge tip in a direction opposite to the rotating direction of the drill with respect to the wall surface facing the rotational direction of the chip discharge groove. is possible,
Another object of the present invention is to provide a throw-away drill that can prevent chip clogging.

An embodiment of this invention will be described below with reference to FIGS. 3 and 4. In the figure, reference numeral 11 denotes a drill body, and chip discharge grooves 15 and 16 extending from the tip toward the rear end are formed on the outer periphery of the drill body.
A tip 12 for cutting the center of the hole to be drilled is removably attached to the inside of the tip of the wall surface facing the rotational direction of one of the chip discharge grooves 15 by a tightening bolt 14. Other chip discharge groove 1
A cutting edge tip 13 for cutting the outer periphery of the hole to be drilled is removably attached to the outside of the tip of the wall surface facing the direction of rotation of the hole 6 by means of a tightening bolt 14. Further, an outer circumferential cutting edge tip 18 for chamfering is detachably attached to the outer circumferential portion of the rear end of the wall surface of the chip discharge groove 15 facing in the rotational direction by a tightening bolt 19. The above configuration is similar to the conventional example described above.

However, in this drill, the chip discharge groove 1
A recess 17 is formed at the rear end of the wall surface facing the rotation direction of the rotor 5. The depth of this recess 17 is greater than the thickness of the outer peripheral cutting edge tip 18. A peripheral cutting edge tip 18 is disposed in this recess 14. As a result, the peripheral cutting edge tip 18 is displaced in the direction opposite to the rotation direction of the drill with respect to the tip side portion of the wall surface facing the rotation direction of the chip discharge groove 15 located on the tip side. The distance from the tip 12 to the tip 18 is approximately equal to the thickness of the workpiece 20.

However, when drilling with such an indexable drill, the peripheral cutting edge tip 1
8 is shifted in the direction opposite to the rotational direction of the drill with respect to the wall surface facing the rotational direction of the chip evacuation groove 15, the chips generated from the workpiece 20 by the tip 12 are transferred to the outer peripheral cutting edge. The chips are smoothly discharged to the outside through the chip discharge groove 15 without contacting the chips 18, so that the peripheral cutting edge 18 is not damaged by abrasion due to the chips, or the chips are clogged in the chip discharge groove 15. It is possible to prevent this from happening.

In the above embodiment, the peripheral cutting edge tip 18 is installed in the chip discharge groove 15 in which the tip 12 is installed, but the chip discharge groove 16 in which the other tip 13 is installed It may be attached to

Further, in the above embodiment, the outer cutting edge tip 18 is used for chamfering, but the invention is not limited to this. For example, as shown in FIG. It is also possible to perform the counterboring and counterboring at the same time. Further, an outer circumferential cutting edge tip for chamfering may be further provided behind the outer circumferential cutting edge tip 18, so that drilling, counterboring, and chamfering can be performed simultaneously.

As explained above, according to the throw-away drill according to this invention, the peripheral cutting edge tips are aligned in the direction of rotation of the drill with respect to the tip side portion of the wall surface facing the rotation direction of the adjacent chip evacuation groove. Since they are arranged offset in the opposite direction, the chips generated from the workpiece by the tip of the cutting edge are smoothly discharged to the outside through the chip discharge groove without contacting the tip of the outer cutting edge. Therefore, it is possible to prevent the outer cutting edge tip from being damaged by abrasion, thereby increasing the life of the outer cutting edge tip, and preventing chips from clogging in the chip discharge groove, which in turn can damage the drill body. This has effects such as being able to prevent damage to the product.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an example of a conventional indexable drill, Fig. 2 is a view taken along the - line, Fig. 3 is a side view showing an embodiment of this invention, and Fig. 4 is a side view showing the - line. The arrow view and FIG. 5 are side views showing another embodiment of this invention. 11... Drill body, 12, 13... Tip cutting edge tip, 15, 16... Chip discharge groove, 17... Recessed portion, 18... Peripheral cutting edge tip.

Claims (1)

[Scope of utility model registration request] Chip discharge grooves 15, 16 extending from the tip toward the rear end are formed on the outer circumference of the drill body 11, and tip cutting chips 12, 13 are provided at the tip of the wall surface facing the rotation direction of the chip discharge grooves 15, 16. is attached,
An outer peripheral cutting edge tip 18 is provided at the rear end portion of the wall surface facing the rotational direction of the chip ejection portions 15, 16, and the peripheral cutting edge tip 18 is located opposite to the rotational direction with respect to the wall surface portion facing the rotational direction of the chip evacuation grooves 15, 16 adjacent to the tip end thereof. A throw-away drill that is installed in a direction that is shifted.