JPH0111371Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an annular cutter that drills a large diameter hole by individually cutting annularly with two blades, an outer cutter and an inner cutter.

Since drilling with a twist drill has a large cutting resistance, the drilling speed cannot be increased unless sufficient thrust is applied either mechanically or manually.

On the other hand, annular cutters drill large diameter holes by cutting in an annular shape, so they can be expected to perform high-speed drilling with low cutting resistance, and their popularity has increased significantly in recent years when drilling relatively large diameter holes. It's summery.

However, the circular cutter has not only many advantages, but also some disadvantages. Part 1 is
As the drilling depth increases, it becomes difficult to discharge the chips, and the second problem is that the slag formed inside the cutter bites into the cutting edge and becomes difficult to discharge.

In order to improve the discharge of chips, for example, an annular cutter has been proposed in which the cutting blade is divided into an inner cutter and an outer cutter, and the chips are discharged in two.
Since both of the divided chips are discharged through a common flute formed on the outer circumferential surface of the annular cutter, the effect of dividing into two is halved and the discharge resistance is extremely large. If this was not removed manually, the annular cutter would be damaged.

In view of the fact that even an annular cutter equipped with an inner cutter and an outer cutter has the above-mentioned drawbacks, the present invention is designed to collect chips cut separately by the outer cutter and inner cutter into independent galets,
The purpose is to discharge it in a separated state through a flute.

An embodiment of the present invention will be explained below based on the drawings.

Reference numeral 10 designates a cutter main cylinder, which is no different from a conventional annular cutter in that a shank portion 12 protruding from the top of the main cylinder 10 is attached to an arbor of a motor (not shown).

The outer peripheral surface 18 of the cutter main cylinder 10 has a plurality of lands (the so-called hill portion LAND that remains when a flute is formed...also referred to as margin MARGIN) 20.
is provided protrudingly with a predetermined twist angle, and an outer cutter is provided on the end face of the main cylinder, located in front of the land 20 in the circumferential direction of the main cylinder, and extending along the land with a predetermined twist angle. 22 is fixed. Reference numeral 24 denotes a gullet formed forward in the circumferential direction along the outer cutter, and chips formed by the cutting action of the outer cutter exit to the outer circumferential surface portion 18 of the main cylinder body 10 through this gullet 24. Thereafter, it is discharged from the annular hole 16 along the same surface portion 18. The inner cutter 2 is located approximately in the middle of the outer cutters 22, 22.
6 is fixed in the same manner as the outer cutter, and a gullet 28 is formed in the same way as the outer cutter and located at the front in the circumferential direction, and the chips cut by the inner cutter 26 are discharged through the gullet 28. It is becoming more and more common.

As shown in FIGS. 4 and 5, only one inner cutter 26a among the plurality of inner cutters 26 is slightly protruded in the centripetal direction than the inner circumferential surface 30 of the cutter main cylinder 10. 32, and therefore the inner cutter 2
The outer diameter of the slug 34 cut by the slag 6a is smaller than the inner diameter of the main cylinder 10. Therefore, in the example shown in FIGS. 4 and 5, when the slag 34 is separated from the workpiece 14,
The slug 34 will easily separate from the annular cutter upon completion of drilling.

FIG. 3 shows the outer blade 22 when drilling the annular hole 16.
This shows the state in which the inner cutter 26 is responsible for cutting, with the outer cutter and the inner cutter taking charge of approximately half the cutting. However, the heights of the outer cutter 22 and the inner cutter 26 do not necessarily have to be the same as shown in the figure. However, in any case, if the heights of the outer and inner blades are not the same, the load will be concentrated on a specific cutting edge, so care must be taken in this regard.

Note that it goes without saying that both the outer cutter and the inner cutter must be formed to have a rake angle or relief angle necessary for cutting, and this point is common knowledge for cutlery, so the explanation will be omitted.

The outer cutter 22 and the inner cutters 26, 26a are made of high-speed steel or carbide, and are each fixed to the main cylinder 10 by brazing or the like.

The annular cutter of the present invention has been described above based on the embodiments. However, the present invention not only performs cutting independently with the inner and outer cutters, but also uses gullets provided individually adjacent to the inner and outer cutters. Since the chips are discharged individually, there is no interference between the chips while they are being discharged, and the discharge is performed smoothly, resulting in smooth cutting and sufficient feed speed as an annular cutter, resulting in efficiency. It has the advantage of being able to perform good drilling.

In addition, since the outer cutter is installed adjacent to the land that protrudes from the cutter main cylinder, it is easier to cut an annular hole with a large radial width, and the outer cutter is placed adjacent to the land that projects from the main cylinder of the cutter. This has the effect of holding the metal more firmly and making it easier to discharge chips cut by the outer cutter through the gullet.

Note that when some of the inner cutters are made to protrude slightly in the centripetal direction from the inner peripheral surface of the main cylindrical body 10 like the inner cutter 26a shown in the embodiment, the outer diameter of the slag to be cut will be smaller than that of the main cylinder. The diameter is smaller than the inner diameter of the body 10, which makes it easier to drain the slag.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a front view, Fig. 2 is a longitudinal sectional front view during drilling, and Figs. 3 and 4 are enlarged views of the overlapping state of the outer cutter and inner cutter. The vertical sectional front view shown in FIG. 5 is an enlarged bottom view showing the arrangement of the outer cutter, inner cutter, gullet, and land. 10... Cutter main cylinder body, 20... Land, 22...
Outer blade, 24, 28...garet, 26...inner blade.

Claims (1)

[Scope of utility model registration request] A plurality of lands 20 extending in the axial direction with a required twist angle are protruded on the outer peripheral surface of the cutter main cylinder 10, and the ends of the cutter main cylinder are provided with lands 20 in the rotational direction of the circumference of the main cylinder. An outer cutter 22 is provided at a position adjacent to the front of the cutter, and an inner cutter 26 is provided at a position approximately centrally between these outer cutters, with its inner and outer circumferential surfaces substantially matching the inner and outer circumferential surfaces of the cutter main cylinder. Additionally, gallets 24 and 28 for discharging chips are provided at positions adjacent to the front of the outer cutter and inner cutter in the rotational direction.
A circular cutter with individual cutters.