JPH1034597A - Cutting edge for rotary cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bore a hole without generating lateral vibration by providing a cutting edge on the outer peripheral side of a ring groove and a cutting edge on the inner peripheral side as the cutting edge of a rotary cutting tool for opening a hole in material to be bored by cutting a ring groove, and making the width of the inner peripheral side cutting edge larger than that of the outer peripheral side cutting edge. SOLUTION: A shaft 5 is provided protrusively from the front face center of a base 6 provided with a fitting shaft 60. A cutting edge 2 and a restricting cutting edge 4 are fitted to one end of the base 6, and a scraping cutting edge 3 and a restricting cutting edge 4 are fitted to the other end of the base 6. The cutting edges of this rotary cutting tool is mounted to a power tool using the fitting shaft 60. At the time of boring material to be bored, the tip of the shaft 5 is positioned at the center of a hole to be opened, and in this state, the rotary cutting tool is rotated to cut with the cutting edge 2 and the scraping cutting edge 3, thus opening a hole piercing the material to be bored. The width of the cutting edge 2 is to be 60-80% of cutting width, and the width of the scraping cutting edge 3 is to be the same as the cutting width. Load at the time of cutting is thereby reduced, and cutting speed is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cutting tool blade for drilling a large-diameter hole in an object to be drilled.

[0002]

2. Description of the Related Art As a rotary cutting tool for drilling a large-diameter hole in an object to be drilled, in addition to a so-called hole saw having a blade formed at an opening edge of a cylindrical blade, a rotary cutting tool is provided on a circumference. Some types have multiple blades. As shown in FIG. 5, this type has a cutting blade 2 for cutting on the outer periphery serving as an inner peripheral surface of the hole and a scraping blade 3 for cutting on the inner periphery, and the shaft 5 is These blades 2,3 in the center
The hole 7 is cut out by drilling the object 7 to be drilled.

Conventionally, the two types of blades 2 and 3 have the same blade width. That is, assuming that the width (cutting width) of the annular groove cut by the two blades 2 and 3 is A, the blade width of both the blades 2 and 3 is set to a value of 60 to 80% of the cutting width A, and the cutting blade 2 is set on the outer peripheral side. Then, the shaft 5 is fixed to a base 6 provided at the center in a state where the scraping blade 3 is swung to the inner peripheral side.

[0004]

In this case, since the blades 2 and 3 are provided at positions sandwiching the shaft 5, each of the blades 2 and 3 is provided.
The gap formed between the groove and the groove is generated in the same direction, which causes a problem that a lateral vibration indicated by an arrow C direction is generated during cutting. The present invention has been made in view of such a point, and an object of the present invention is to provide a rotary cutting tool blade that can perform drilling without generating lateral vibration.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a rotary cutting tool blade for drilling a hole in an object to be drilled by cutting an annular groove in the object to be drilled, comprising: An inner peripheral cutting blade is provided, and the blade width of the inner peripheral cutting blade is made larger than the outer peripheral cutting blade. The purpose of this is to prevent the gap for causing the inner peripheral cutting blade to touch the side.

It is also preferable that the outer peripheral side cutting blade is higher than the inner peripheral side cutting blade, and that the outer peripheral side cutting blade and the inner peripheral side cutting blade are flat.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described. In FIGS. 1 and 2, reference numeral 6 denotes a base provided with a mounting shaft 60. Is protruding. The cutting blade 2 and the limiting blade 4 are attached to one end of the base 6, and the scraping blade 3 and the limiting blade 4 are attached to the other end of the base 6. In the drawing, reference numeral 61 denotes a screw for mounting and fixing the blades 2, 3, and 4 arranged on the same circumference.

The blade of this rotary cutting tool is
By attaching the shaft 5 to a power tool such as an electric drill by using the tool and rotating the shaft 5 with the tip of the shaft 5 positioned at the center of the hole to be drilled, as shown in FIG. As shown in the figure, by performing cutting with the cutting blade 2 and cutting with the scraping blade 3, an annular groove is cut into the drilled object 7, and the annular groove is cut until it penetrates the drilled object 7. In this case, a hole is drilled in the object 7 to be pierced. At this time, the limit blade 4 prevents the depth of cut into the object 7 to be perforated from becoming too deep, thereby enabling smooth drilling. .

Here, the blade width W2 of the cutting blade 2 for cutting the outer peripheral side of the annular groove is set to 60 to 80% of the cutting width A which is the width of the annular groove. The blade width W3 of the scraping blade 3 for cutting the circumferential side is:
It is the same as the cutting width A. For this reason, as is clear from FIG. 4, the side contact is restricted by the shaft 5 and the scraping blade 3, so that the side contact does not occur and the load at the time of cutting is reduced accordingly. In addition, the cutting can be performed with a small force, and the cutting speed can be improved to improve the working efficiency.

Further, the cutting blade 2 and the scraping blade 3 in this case are higher than the cutting blade 3 by about 0.1 to 0.5 mm. Due to the difference x, in the cutting shown in order from (a) to (h) in FIG. 3, the cutting on the outer peripheral side of the annular groove by the cutting blade 2 precedes the cutting by the scraping blade 3, Therefore, the outer peripheral side of the annular groove, that is, the inner peripheral surface of the opened hole has a beautiful finish. The finish on the inner peripheral side of the annular groove may have a “burr” or the like. However, there is no problem because the inside of the annular groove is a part that is finally to be discharged and removed.

The above-mentioned blades 2, 3, and 4 are formed as cemented carbide tips 20, 30, and 40 at the tips.
Instead of using an arc-shaped one having a cross section cut at a plane perpendicular to the axis and using an arc-shaped one centered on the axis 5, a flat one is used.
In addition to securing the blade widths W2 and W3 with a width of 30, the width of the portion excluding the carbide tips 20 and 30 is the same as the blade widths W2 and W3.
By making it smaller than 3 and fitting it into the annular groove to be cut, it does not hinder cutting of the annular groove due to the flat shape. In addition, the limiting blade 4
Although the width is substantially the same including the carbide tip 40, it does not hinder cutting because it is also contained in the annular groove. In the case of an arc-shaped cross section, the cost is extremely high because of its difficulty in manufacturing. However, since the blades 2, 3, and 4 used here are flat, the cost is much lower. Can be manufactured.

[0012]

As described above, in the present invention, the blade width for the inner peripheral side cutting is larger than the blade width for the outer peripheral side cutting blade. Is to prevent the occurrence of a gap that causes side contact, and therefore, a stable cutting operation can be performed speedily with a small force and the operation efficiency can be increased.

If the outer peripheral cutting blade is higher than the inner peripheral cutting blade, the finish of the inner peripheral surface of the hole formed in the object to be drilled can be kept clean. Further, if the outer peripheral side cutting blade and the inner peripheral side cutting blade are formed in a flat plate shape, it can be manufactured at a much lower cost as compared with the case of using a circular cross section.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention, in which (a)
Is a plan view, and (b) is a front view.

FIG. 2 is a side view of the same.

FIGS. 3 (a) to 3 (h) are explanatory views showing a cutting process of the above.

FIG. 4 is an explanatory diagram of the above.

FIG. 5 is an explanatory diagram showing a cause of occurrence of lateral touch in a conventional example.

[Explanation of symbols]

 2 cutting blade 3 scraping blade

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[Procedure amendment]

[Submission date] September 2, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (3)

[Claims] 1. A blade of a rotary cutting tool for drilling a hole in an object to be drilled by cutting an annular groove on the object to be drilled, comprising: a cutting blade on an outer peripheral side of the annular groove; and a cutting blade on an inner peripheral side of the annular groove. And a blade of the rotary cutting tool, wherein a blade width of the inner peripheral side cutting blade is larger than a blade width of the outer peripheral side cutting blade. 2. The rotary cutting tool blade according to claim 1, wherein the outer peripheral cutting blade is higher than the inner peripheral cutting blade. 3. The rotary cutting tool blade according to claim 1, wherein the outer peripheral side cutting blade and the inner peripheral side cutting blade are flat.