JPH0710447B2 - Annular drilling blade - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an annular drilling blade, and more specifically, by dividing the central angle of the cutting blade setting portion of the tip of a cylindrical blade body into even-numbered regions. The present invention relates to an annular piercing blade having cutting blades provided at respective divided portions symmetrically positioned with respect to the central axis of the blade body.

[Conventional technology]

Conventionally, an annular drilling blade is provided at one end of a cylindrical blade body,
It is a tool that is provided with a large number of cutting blades having a thickness substantially equal to the thickness of a cylinder and is driven to rotate around an axis to leave a core portion and punch a round hole having a substantially cylindrical outer diameter.

Therefore, it is characterized by having a large number of cutting edges in an annular shape, and it is necessary that effective grinding can be performed quickly and easily regardless of whether the large number of cutting edges is created or re-ground.

Further, it is necessary to mount a conventional annular drilling tool on a spindle of a drilling machine and perform a drilling process to secure a hole for drilling with a required accuracy.

[Problems to be solved by the invention]

Examples of prior art relating to the present invention include Japanese Patent Publication No. 59-49844 and Japanese Patent Publication No. 52-15832. The above-mentioned prior art discloses a configuration in which the teeth are arranged at symmetrical positions and a configuration in which the height dimensions of the inner, middle, and outer blades are different. There are problems that need to be further improved, such as improvement in the adhesion of burrs.

[Means for solving problems]

In view of the conventional problems as described above, the present invention provides an annular perforated blade provided with a plurality of inner blades, middle blades and outer blades at the tip of a cylindrical blade body, and has a pair of the same size and shape. Each inner blade,
The inner blades and the outer blades are arranged at symmetrical positions about the axis of the tool body, respectively, and the inner blade, the middle blade, and the outer blade are arranged in this order from the front side as viewed in the rotation direction of the tool body. The blade height is reduced in the order of the blade, the middle blade, and the outer blade, and each of the inner blade, the middle blade, and the outer blade is formed as a single-sword tip blade that is inclined so that the radial outer direction becomes higher. is there.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view showing an annular drilling blade of the present invention. Referring to FIG. 1, the annular drilling blade 1 has a cylindrical blade body 3
The shank portion 5 is formed, and the blade main body 3 has a plurality of upwardly twisted grooves 7 formed at a depth of about half the maximum thickness thereof on the outer periphery at substantially equal pitches from the lower tip portion.

The shank portion 5 is a portion which is attached to a drilling machine and driven to rotate, and through holes 9 through which cutting oil is passed are provided at the top and bottom.

The cutting edge portion 11 of the embodiment shown in FIG. 1 and FIG. 2 has three types of inner blades 13, middle blades 15 and outer blades 17 having a set of 1/2 (180 degrees) of the circumference. Blades are formed in order. Therefore, the height position of each blade in the inner blade 13, the middle blade 15, and the outer blade 17 is sequentially shortened in the axial direction of the tool body 3,
It is provided with a height such that the rear cutting edge is delayed and the same level surface of the workpiece is cut. In addition to a set of 1/2 (180 degrees) of the circumference described above, a set of even numbers of multiples of 2 such as 1/4 (90 degrees) of the circumference and 1 of the circumference
It may be / 8 (45 degrees).

On the front side in the rotational direction of each of the cutting edges 13, 15 and 17, there is a garret part 13G, which connects the above-mentioned spiral groove 7 and the cylindrical part.
15G and 17G are provided.

Each of the above-mentioned gullets 13G, 15G and 17G is provided on the spiral groove 7 side with an upward inclination, and the chips 19 from the respective cutting edges 13, 15 and 17 are guided to the spiral groove 7, and further in the spiral groove 7. It is moved above the annular drilling blade 1 shown in FIG.

The inner wall portion of the outer blade 17 is provided with a back lead groove 21 which serves as an oil groove for helping the inflow of cutting oil into the cutting portion. As is apparent from FIG. 2, cutting blades are provided in the respective divided portions at symmetrical positions about the central axis of the tool body, and the cutting blades arranged in the divided portions at the symmetrical positions have substantially the same size and diameter. Is configured to.

FIG. 3 is a development view of the inner blade 13, the middle blade 15, and the outer blade 17 of FIG. 1, and the lower end surface of the set of three blades is an inner blade having a horizontal surface and a contact angle α of 2 to 5 degrees. It is on a medium-high arc line that rises from 13 toward the outer blade 17. In FIG. 4 as viewed from the left side of FIG. 3, the lower end surfaces of the cutting blades of the same set of three blades are in a parallel state forming a concave curved surface (curved curved surface in the middle).

Further, as is apparent from FIG. 4, the lower side of the outer side of the inner blade 13 and the middle blade 15 is cut away by the concave curved surface, and the middle blade 15 has a cutting edge width of 2/3 of the outer blade 17, Inner blade 13 is outer blade 17
It has a cutting edge width of about 1/3.

Note that, for example, FIG. 5 is a view of the inner blade 13 of FIG. 4 seen from below, and as described above, both the lower surface of the inner blade 13 and the shaved portion shown by hatching are both concave curved surfaces. . Therefore, as seen in FIG. 4, each cutting edge 13, 15 and 1
Each of 7 is a single-sword tip blade that is inclined outward of the radius of the blade body 3.

The side flanks of each of the cutting edges 13, 15 and 17 are inwardly convex curved surfaces that are regulated by the outer circumference of the grinding wheel.

FIG. 6 shows a conventional cutting blade lower surface (A) and a cutting blade lower surface (B) of the present invention. The cutting blade lower surface of the present invention is a concave curved surface as described above. The grindstone is rotated and ground around a distance parallel to the cutting edge. Therefore, in the present invention, unlike the prior art (A), the polished surface of the cutting edge is smooth and chipping phenomenon does not occur during cutting.

Although not directly related to the present invention, FIG. 7 shows a reference example when the inner blade 13, the middle blade 15, and the outer blade 17 are inclined so that the inside of each blade is higher. In FIG. 7, cutting part
11 has a set of three types of blades, an inner blade 13, a middle blade 15, and an outer blade 17, which are formed in a set of 1/2 (180 degrees) of the circumference similar to that shown in FIG. is there. Galette portions 13G, 15G and 17G are provided on the front side of the respective cutting edges 13, 15 and 17 in the rotation direction so as to communicate the thread groove 7 with the inside of the cylinder.

Although not shown in the drawings, each of the gullet portions 15G and 17G described above is provided on the twist groove 7 side with an upward inclination,
The chips 19 are guided by the cutting blades 13, 15 and 17 into the twist groove 7, and the twist groove 7 actually causes the annular drilling blade 1 shown in FIG.
Of the workpiece W and is carried to the top of the workpiece W.

As described above, the cutting portion 11 includes the inner blade 13, the middle blade 15 and the outer blade 17.
The blade body 3 as a whole has an inner and outer peripheral surface with a cutting clearance angle θ _{1 in the} cutting direction (axial direction).
Is equipped with.

Further, in the annular drilling blade 1 of this reference example, the inner blade height, the inner blade height 15, and the outer blade height 17 are both shorter than the outer blade height by Δα, and the angle θ _{2 is} the same as in FIG. In the upper right, it is configured higher.

Therefore, the chips 19 illustrated in FIG. 7 are inclined downward toward the outside as shown in the drawing in the form of a thin plate having a thin radial length of the cutting edge 13. Will be discharged in the following direction.

In addition, in this reference example, since the inner blade 13 is inclined by the angle θ ₂ , when the blank is cut out, a burr due to the angle θ ₂ is generated in the lower portion of the blank, which is not desirable. Absent.

〔effect〕

As will be understood from the above description of the embodiments, in short, the present invention provides an annular perforated blade having a plurality of inner blades 13, middle blades 15 and outer blades 17 at the tip of the cylindrical blade body 3. The same size and shape of each inner blade 13, each middle blade 15 and each outer blade 1
7 are respectively arranged at target positions around the axis of the blade body 3, and the inner blade 13, the middle blade 15, and the outer blade 17 are arranged in this order from the front side in the rotation direction of the blade body 3 and Blade 13,
The inner blade 1 and the outer blade 17 are arranged in the order of decreasing blade height.
3, each of the middle blade 15 and the outer blade 17 is formed as a single sword tip blade that is inclined so that the radial outer direction becomes higher.

As is apparent from the above configuration, in the present invention, a plurality of inner blades 13, middle blades 15 and outer blades 17 are provided, and each pair of blades of the same size and shape are arranged symmetrically, Of course, the subdivision of the powder and the canceling of the radial component force at the time of cutting are performed, the discharge property of chips, the suppression of vibration are improved and the processing accuracy is improved, but particularly in the present invention. The blade edges of the inner blade 13, the middle blade 15, and the outer blade 17 are formed so as to be inclined so that the outer radial direction is higher, and are formed as a single-sword tip blade.
The blade edges of Nos. 5 and 17 are sharp, and the biting ability of each blade with respect to the work is good. In addition, the inner blade 13, the middle blade 15, and the outer blade 17 have a smaller height dimension in this order, and since they are configured as a single-sword tip blade that is inclined so that the radial outer direction becomes higher, the moment the blank is cut out from the workpiece Is in a state in which the tip of the inner blade 13 has penetrated the work in advance, but the outer blade 17 is in a state of not penetrating, which reduces the adhesion of burrs to the blank cut out from the work and Large inner blade 15, outer blade 17
Is a mode in which the step portion after the inner blade 13 is cut is sequentially cut, and the load is smaller than that of the preceding inner blade 13, so that the torque for rotating the annular drilling tool can be further reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an annular piercing blade of the present invention. FIG. 2 is a partial enlarged bottom view of FIG. FIG. 3 is a development view of each cutting blade at the tip of the blade main body. FIG. 4 is a partial cross-sectional view during the punching work of the present invention. FIG. 5 is a bottom view of FIG. FIG. 6 is an explanatory view showing the grindstones of the cutting edge. FIG. 7 is an explanatory view showing a reference example of the cutting portion in the present invention. (Explanation of the symbols indicating the main parts of the drawing) 1 …… Annular drilling blade 3 …… Blade body 11 …… Cutting part 13 …… Inner blade 15 …… Middle blade 17 …… Outer blade 19 …… Chips 21 …… Back lead groove

Claims (1)

[Claims] Claims: 1. An annular piercing blade comprising a plurality of inner blades (13), middle blades (15) and outer blades (17) at the tip of a cylindrical blade body (3), forming a pair. Inner blades of the same shape (13),
The inner blades (15) and the outer blades (17) are arranged at symmetrical positions about the axis of the tool body (3), respectively, and the inner blades are seen from the front side when viewed in the rotation direction of the tool body (3). (13), middle blade (15), outer blade (17) in this order and inner blade (1
3), the middle blade (15), the outer blade (17) in order of decreasing blade height, the inner blade (13), the middle blade (15) and the outer blade (17) are An annular piercing blade characterized by being formed on a single-sword tip blade that is inclined so as to be higher.