JP3223216U - Countersunk drill bit - Google Patents

Abstract

Provided is a countersink drill bit having a high drill structure strength, a long service life, accurate and quick drilling, and high machining production efficiency. A front end drill, a tapered portion, a rear end drill, and a polygonal body are provided. The outer diameter of the front end drill 11 is smaller than the outer diameter of the rear end drill 13. The rear end of the front end drill 11 is connected to the rear end drill through a tapered portion 12. The outer diameter of the front end of the tapered portion 12 is the same as the outer diameter of the rear end of the front end drill 11, and the outer diameter of the rear end is the same as the outer diameter of the front end of the rear end drill 13. The front end drill 11 has two or more excavation blades 2 and two or more chip discharge grooves 3 and has the same helix angle. Each excavation blade 2 and each chip discharge groove 3 of the front end drill 11 are directly extended to the taper portion 12 and the rear end drill 13, and the front end drill 11, the taper portion 12 and the rear end drill 13 are extended to each other. . The polygonal body 14 is located at the rear end of the rear end drill 13. [Selection] Figure 1

Description

  The present invention relates to a countersunk drill bit for drilling countersunk hole for countersunk head screw in an article.

  Generally, the prior art machining process for completing a screw hole by drilling a screw hole first drills one through hole in a workpiece using a drill having a small outer diameter, and then drills the drill. The screw hole is completed by removing and replacing with a milling cutter having a predetermined large outer diameter, and processing the center position of the drilled through hole with the milling cutter.

In the above-described conventional technology, the drill is processed twice by exchanging the drill twice through two steps. For this reason, this processing system has the following drawbacks.
(1) Since two machining operations are required, machining quality becomes unstable due to human factors.
(2) Since two processes are required, time and labor are required, and the production efficiency is lowered.

Accordingly, those skilled in the art can drill a screw hole in an article by providing an improved version of a drill in which two drills having different outer diameters are connected and fixed to each other with the same axis and combined together. Is simplified. This known composite drill for drilling a screw hole is a combination of a drill with a large outer diameter on a coaxial line in a subsequent stage with a small outer diameter drill at the front end by a fixing method using a pilot pin.
Such an integrated drill combined and integrated has the following drawbacks in actual use.
(1) In the method of combining by the method of fixing the pilot pin, since the structural strength of the entire drill is lowered, the service life is shortened.
(2) Since the two front and rear drill blades and the chip discharge groove are not connected to each other and chips cannot be discharged smoothly, the resistance to the chips increases, which directly affects the drilling speed and production efficiency. Influenced.

  For this reason, the development of drills with high drill structural strength, long service life, precise and quick drilling and high machining production efficiency is the goal of those skilled in the art.

  The present invention has been made in view of these circumstances, and the present invention aims to provide a drill having a high drill structure strength, a long service life, accurate and quick drilling, and high machining production efficiency. And

In order to solve the above problems, a countersink drill bit (1) according to an aspect of the present invention includes a front end drill (11) integrally formed at a front end, a tapered portion (12), and a rear end drill (13). And a polygonal body (14) positioned at the rear end of the rear end drill (13).
The outer diameter of the front end drill (11) is smaller than the outer diameter of the rear end drill (13), and the rear end of the front end drill (11) is connected to the rear end drill via a tapered portion (12) provided with an inclination angle, The front end of the tapered portion (12) connected between the rear end of the front end drill (11) and the front end of the rear end drill (13) has an outer diameter that is the same as the outer diameter of the rear end of the front end drill (11). The outer diameter of the tapered portion (12) is the same as the outer diameter of the front end of the rear end drill (13). The front end drill (11) has two or more excavation blades (2) and two or more chip discharge grooves (3), and each excavation blade (2) and each chip discharge groove (3) have the same twist. Has horns. Each excavation blade (2) and each chip discharge groove (3) of the front end drill (11) extend directly to the taper portion (12) and the rear end drill (13) at the same twist angle, and the front end drill (11). And the taper portion (12) and the rear end drill (13) are extended to each other.
The polygonal body (14) is located at the rear end of the rear end drill (13).
An oblique cut surface (121) is formed in the taper part (12) between the two chip discharge grooves (3) adjacent to each other. The left end (121A) side of the oblique cut surface (121) is shorter than the right side (121B) side and is connected to the rear end of the chip discharge groove (3) of the taper portion (12) (13). The front end pitch (3A) of the chip discharge groove (3) is larger than the rear end pitch (3B) of the chip discharge groove (3) extended to the rear end of the rear end drill (13).

  The front end drill, taper part and rear end drill, which are integrally formed at the front end of the countersink drill bit, the drilling blade and the chip discharge groove that extend to each other and have the same helix angle, make chip discharge smooth. Thus, the practicality of being able to drill easily and quickly is reliably achieved.

It is a perspective view which shows the external appearance of the countersink drill bit which concerns on 1st Embodiment of this invention (it is provided with three excavation blades and three chip discharge grooves). It is a top view of FIG. FIG. 3 is a right side view of FIG. 2. It is a top view of the countersink drill bit which concerns on 2nd Embodiment of this invention (it is provided with two excavation blades and two chip discharge grooves). FIG. 5 is a right side view of FIG. 4.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims of utility model registration. In addition, all the configurations described below are not necessarily essential requirements of the present invention.

(First embodiment)
First, a first embodiment will be described based on FIGS.
The countersink drill bit (including three drilling blades and three chip discharge grooves) according to the first embodiment of the present invention is the most preferable embodiment, and is a front end integrally formed with the front end of the countersink drill bit 1 A drill 11, a tapered portion 12, a rear end drill 13, and a polygonal body 14 positioned at the rear end of the rear end drill 13 are provided.
The outer diameter of the front end drill 11 is smaller than the outer diameter of the rear end drill 13, and the rear end of the front end drill 11 is connected to the rear end drill 13 via a tapered portion 12 provided with an inclination angle.
The front end of the tapered portion 12 connected between the rear end of the front end drill 11 and the front end of the rear end drill 13 has an outer diameter that is the same as the outer diameter of the rear end of the front end drill 11. The rear end has the same maximum outer diameter as the outer diameter of the front end of the rear end drill 13.

As shown in FIGS. 1 to 3, the front end drill 11 has two or more excavation blades 2 and two or more chip discharge grooves 3. The excavating blade 2 and the chip discharge groove 3 of the front end drill 11 are directly extended to the tapered portion 12 and the rear end drill 13 with the same helix angle, and the front end drill 11, the tapered portion 12 and the rear end drill 13 are extended to each other. It is.
An oblique cut surface 121 is formed on the tapered portion 12 between the two adjacent chip discharge grooves 3. The side of the left side 121A of the oblique cut surface 121 is shorter than the side of the right side 121B, and the front end pitch 3A of the chip discharge groove 3 of the rear end drill 13 connected to the rear end of the chip discharge groove 3 of the tapered portion 12 is: It is larger than the rear end pitch 3B of the chip discharge groove 3 extended to the rear end of the rear end drill 13.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS.
A countersink drill bit (including two drilling blades and two chip discharge grooves) according to a second embodiment of the present invention includes a front end drill 11 integrally formed at the front end of the countersink drill bit 1 and a tapered portion 12. And a rear end drill 13 and a polygonal body 14 positioned at the rear end of the rear end drill 13.
The outer diameter of the front end drill 11 is smaller than the outer diameter of the rear end drill 13, and the rear end of the front end drill 11 is connected to the rear end drill 13 via a tapered portion 12 provided with an inclination angle.
The front end of the tapered portion 12 connected between the rear end of the front end drill 11 and the front end of the rear end drill 13 has an outer diameter that is the same as the outer diameter of the rear end of the front end drill 11. The rear end has the same maximum outer diameter as the outer diameter of the front end of the rear end drill 13.

As shown in FIGS. 4 and 5, the front end drill 11 has two excavating blades 2 and two chip discharge grooves 3. The excavating blade 2 and the chip discharge groove 3 of the front end drill 11 are directly extended to the tapered portion 12 and the rear end drill 13 with the same helix angle, and the front end drill 11, the tapered portion 12 and the rear end drill 13 are extended to each other. It is.
An oblique cut surface 121 is formed on the tapered portion 12 between the two adjacent chip discharge grooves 3. The side of the left side 121A of the oblique cut surface 121 is shorter than the side of the right side 121B, and the front end pitch 3A of the chip discharge groove 3 of the rear end drill 13 connected to the rear end of the chip discharge groove 3 of the tapered portion 12 is rear. It is larger than the rear end pitch 3B of the chip discharge groove 3 extended to the rear end of the end drill 13.

  The draft is smoothly formed by a front end drill, a tapered part, a rear end drill, and a drill blade and a chip discharge groove that extend to each other and have the same helix angle. And ensure that the practicality of enabling simple and rapid drilling is achieved.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

DESCRIPTION OF SYMBOLS 1 ... Countersink drill bit 11 ... Front end drill 12 ... Tapered part 121 ... Diagonal cut surface 121A ... Left side 121B ... Right side 13 ... Rear end drill 14 ... Polygon Body 2 ... excavation blade 3 ... chip discharge groove 3A ... front end pitch of chip discharge groove of rear end drill 3B ... rear end pitch of chip discharge groove of rear end drill

Claims (2)

A countersink drill bit (1) comprising a front end drill (11), a tapered portion (12), a rear end drill (13), and a polygonal body (14),
The front end drill (11) is integrally formed with the front end of the countersink drill bit (1), and the outer diameter of the front end drill (11) is smaller than the outer diameter of the rear end drill (13). 11) The rear end is connected to the rear end drill (13) via the tapered portion (12) provided with an inclination angle, and the front end drill (11) is composed of two or more spiral excavating blades (2). And two or more spiral chip discharge grooves (3), and each of the excavating blades (2) and each of the chip discharge grooves (3) has the same twist angle and the tapered portion (12) and the The front end drill (11), the tapered portion (12), and the rear end drill (13) extend to each other directly to the rear end drill (13),
The polygonal body (14) is located at the rear end of the rear end drill (13);
An oblique cut surface (121) is formed in the taper portion (12) between the chip discharge grooves (3) adjacent to each other, and the left side (121A) of the oblique cut surface (121) is the oblique side. Each chip of the rear end drill (13) which is shorter than the right side (121B) side of the cut surface (121) and connected to the rear end of each chip discharge groove (3) of the tapered portion (12). A dish characterized in that the front end pitch (3A) of the discharge groove (3) is larger than the rear end pitch (3B) of the chip discharge groove (3) extended to the rear end of the rear end drill (13). Hole drill bit.   The outer diameter of the front end of the tapered portion (12) connecting the rear end of the front end drill (11) and the front end of the rear end drill (13) is the same as the outer diameter of the rear end of the front end drill (11). The outer diameter at the rear end of the tapered portion (12) is the same maximum outer diameter as the outer diameter at the front end of the rear end drill (13). Countersunk drill bit.

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