JP2001232629A - Drill structure of drilling machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance breaking capability and dischargeability for cut chips by further improving a drill structure in a drilling machine used to punch a small diameter hole. SOLUTION: A leading end of a rotary shaft 1 of the drilling machine for drilling while ejecting the coolant supplied via a channel in the shaft toward the end of the drill by mounting the drill at the leading end of the rotary shaft is formed with a circular flat surface 2 closed except a coolant jet port 3. The drill constituted of a superabrasive segment 10 having a crushing surface 11 in a radial direction of the surface 2 is mounted on the surface 2, and an oblique surface 11a of a direction for reducing a sectional area at the end side of the segment is formed on the surface 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling machine for drilling concrete, stone, building material, glass and the like, and more particularly to a drilling structure for a drilling machine for drilling small diameter holes.

[0002]

2. Description of the Related Art For example, when a decorative panel is attached to a concrete wall of a building, it is necessary to drill a large number of small holes for anchor bolts in the concrete wall. As such a small-diameter drilling machine, a drilling machine having a drill having a cutting portion at the tip of a rotating shaft is used.

[0003] The basic configuration of this kind of drilling machine is that a drill is attached to the tip of a hollow rotating shaft, and a fluid such as air or water supplied through a flow path inside the rotating shaft is ejected from the tip of the rotating shaft. The drill is rotated while rotating, and the drilling is performed while sucking the cutting chips together with the fluid. This is a so-called non-core drill. As a typical conventional example, there is a drilling machine described in Japanese Patent Publication No. 3-4365.

FIG. 5 shows a drill structure of this drilling machine.
As shown in the bottom view of (a) and the longitudinal sectional view of (b), a cutting portion 53 at the tip of the rotating shaft 51 is formed with a slit 55 that opens over a concave tip surface 54 and a side surface. The cutting edge 5 is located at the intersection of
6 is formed. At the time of perforation, compressed air that has passed through the inside of the flow path 52 of the rotating shaft 51 gushes out of the slit 55,
The cutting blade 56 is cooled. According to this drilling machine, air can be supplied easily and smoothly under high-speed rotation,
Drill heat can be suppressed, cutting efficiency can be improved, and air circulation for cooling the drill and discharging and collecting cutting chips is maintained during drilling, so good drilling work throughout It is possible to do.

[0005] However, in the above drill structure, when the drilling diameter is very small, about 12 mm or less, the material to be cut inside the cutting portion is crushed to the extent that it can be discharged by air flow, but the drilling diameter exceeds about 12 mm. And the particle size after crushing is large,
Cutting chips remain without being discharged. In order to solve such a problem, the present applicant has proposed a drill structure in which the crushability of a workpiece is improved in Japanese Utility Model Publication No. 6-25307.

As shown in a bottom view of FIG. 6A and a vertical sectional view of FIG. 6B, this drill structure is provided with a cutting portion 63 at the tip of a rotating shaft 61 having a coolant passage 62. An open space 65 that opens in the shape of a letter is formed.
A cutting blade 66 is formed at the intersection of the tip 5 and the front end surface 64, and a tapered surface 67 inclined toward the center of the base of the cutting portion 63 is provided on the inner wall surface forming the open space 65. By providing the tapered surface 67, the diameter of the perforation becomes 1
Even when it exceeds about 2 mm, the material to be cut in the cutting portion is small and easily crushed by the tapered surface 67.

[0007] Japanese Patent Application Laid-Open No. 11-10425 discloses that, as shown in the bottom view of FIG. 7A and the vertical sectional view of FIG. The jet port 77 is closed and closed to form a flat surface 78.
Describes a drill structure provided with a cutting portion 73 in which a slit 75 is formed. In this drill structure, clogging of the ejection port 77 is prevented by shifting the ejection port 77 from the center of the rotation axis.

[0008]

However, in the actual drilling operation, any of the drilling machines described in the above publications requires that the size of the slit or opening of the cutting portion at the tip of the drill be small.
It is insufficient to completely discharge the cutting chips, and it is inevitable that cutting chips remain. The opening of the cutting portion of the drilling machine described in Japanese Utility Model Publication No. 6-25307 is disclosed in
No. 365, the opening area is larger than the slit of the cutting part of the drilling machine described in JP-A-11-10425, but when the drilling diameter is about 20 to 25 mm, the size of the swarf after crushing also increases accordingly. In addition, the discharge of cutting chips tends to be incomplete.

Further, when the diameter of the drilled hole increases, the area of the tip surface of the drill in contact with the workpiece increases, so that the surface pressure decreases and the drilling efficiency decreases. Further, since the shapes of the slits and the openings are complicated, there is a problem that the manufacturing cost is increased.

The problem to be solved by the present invention is to further improve the drill structure in a drilling machine used for small-diameter drilling to further increase the crushing ability and dischargeability of cutting chips.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a drilling machine for attaching a drill to the tip of a hollow rotary shaft and piercing a fluid supplied through a flow path inside the rotary shaft toward the tip of the drill. In the drill structure, the tip of the rotating shaft is a closed circular flat surface other than the fluid ejection port, and one surface in a direction parallel to the diametric direction of the flat surface or two surfaces in a direction parallel to the radial direction of the flat surface. A drill formed of a superabrasive grain segment having the following features is attached to the flat surface, and a sloping surface is formed on the crushing action surface in a direction in which a cross-sectional area on a segment tip side decreases.

According to the drill structure of the drilling machine of the present invention, the crushing surface of the drill attached to the flat surface at the tip of the rotating shaft is oriented in a direction parallel to the diametrical or radial direction of the flat surface at the tip of the rotating shaft. The crushing action surface is formed with an inclined surface for promoting the crushing of cutting chips. The crushing surface has a size of one surface in a direction parallel to the diameter direction of the flat surface or two surfaces in a direction parallel to the radial direction, and by forming an inclined surface on the crushing surface, it contributes to the crushing of cutting chips. The area is increased and crushing is promoted. In addition to the small crushing of the chips, the crushing surface is parallel to the diametric or radial direction of the flat surface, so the chips move to the outer periphery of the drill where the rotating peripheral speed is high. Since the chips are further finely crushed and the chips flow in one direction from the center of the drill to the outer periphery, the discharge of the chips is improved.

Here, the shape of the segments constituting the drill is such that the bottom surface is substantially semicircular, the crushing action surface in the direction parallel to the diameter direction is inclined, and the bottom shape is approximately 1/4 circular and the radial direction The shape can be a shape in which the crushing action surface in the direction parallel to the shape is inclined, and the shape of the bottom surface is approximately ３ circular and the crushing action surface in the direction parallel to the radial direction is inclined. By adopting such a shape, the side facing the crushing action surface is largely opened, cutting chips are easily discharged to the outside, and clogging of the fluid outlet is also prevented.

In the case of the segment having the above-mentioned shape, the drilling is sufficient even if the drill is constituted by only one segment. If necessary, the segment of the small piece may be attached so as to face the crushing surface. . The crushing action surface may form a slope as a whole, or may form a slope in a part of the height direction. For segments of the shape
It is preferable to form a drill by arranging two fan-shaped segments in opposition to each other. Although the crushing surface is in two orthogonal directions, it is sufficient if the inclined surface is formed on the crushing surface having the same diameter direction. In the case of a segment having the shape of, a drill can be constituted by one segment. The direction of the crushing surface is two orthogonal directions.

As the superabrasive grains used for the segments, diamond abrasive grains and CBN abrasive grains used in conventional superabrasive drills can be used. These abrasive grains are bonded and held by a metal bond to form a segment having a predetermined shape, and this segment is joined to a flat surface at the tip of the rotating shaft to form a drill.
The fluid ejection port is formed so as to open to a portion other than the segment mounting surface.

[0016]

FIG. 1 is a view showing a drill structure of a drilling machine according to a first embodiment of the present invention, wherein (a) is a bottom view and (b) is a sectional view taken along line AA of (a). It is.

In the drill structure of the present embodiment, a segment 10 having a semicircular bottom surface is joined to the flat surface 2 at the tip of the rotating shaft 1 by brazing to form a drill. The segment 10 is formed by bonding and holding diamond abrasive grains with a metal bond.

In this drill structure, the crushing surface 11 for crushing cutting chips is in the diametrical direction of the flat surface 2, and an inclined surface 11a is formed in the lower half of the crushing surface 11 in the height direction. The inclination angle of the inclined surface 11a is approximately 45 degrees with respect to the flat surface 2. The cooling water jet 3 at the tip of the rotating shaft 1 is provided substantially at the center of the flat surface 2.

The drill structure of this embodiment has a crushing surface 1
1 is the diameter direction of the flat surface 2 at the tip of the rotating shaft 1 and the crushing action surface 11 is formed with the inclined surface 11a. Is promoted. In addition to the small crushing of the cuttings, the side facing the crushing surface 11 is largely open, so that the cuttings are easily discharged to the outside.
Clogging of the cooling water outlet 3 is also prevented.

FIG. 2 is a view showing a drill structure of a drilling machine according to a second embodiment of the present invention, wherein (a) is a bottom view and (b).
FIG. 3 is a sectional view taken along line BB of FIG.

In the drill structure of the present embodiment, a segment 20 having a 3/4 semicircular bottom surface is joined to the flat surface 2 at the tip of the rotating shaft 1 by brazing. The segment 20 is a diamond segment like the segment 10 of the first embodiment.

In the case of this drill structure, the crushing surface 21
Is a radial direction orthogonal to the flat surface 2, and forms an inclined surface 21 a on the entire surface of the crushing surface 21. Slope 21
The inclination angle of a is approximately 15 degrees with respect to the flat surface 2.

Also in the case of the drill structure of the present embodiment, the area of the crushing surface 21 is the same as that of the crushing surface 11 of the drill structure of the first embodiment, and the area that contributes to the crushing of the chip is large. Crushing is promoted. Further, since the side facing the crushing surface 21 is open, cutting chips are easily discharged to the outside.

FIG. 3 is a view showing a drill structure of a drilling machine according to a third embodiment of the present invention, wherein (a) is a bottom view and (b).
FIG. 3 is a cross-sectional view taken along line CC of FIG.

The drill structure of this embodiment has a bottom shape of 1
A drill is constituted by / 4 semicircular segments 30a and 30b, and the fan-shaped segments 30a and 30b are attached to the flat surface 2 at the tip of the rotating shaft 1 by brazing so as to face each other. The segments 30a and 30b are diamond segments, like the segment 10 of the first embodiment.

In the case of this drill structure, the inclined surfaces 31a and 31b formed in the respective segments 30a and 30b
Becomes the crushing surface 31, and the crushing surface 31 is in the diametrical direction of the flat surface 2. The inclination angle between the inclined surfaces 31a and 31b is approximately 15 degrees with respect to the flat surface 2.

Also in the case of the drill structure of this embodiment, the area of the crushing surface 31 is the same as the crushing surface 11 of the drill structure of the first embodiment, and the area that contributes to the crushing of the chip is large. Crushing is promoted. Further, since the side facing each of the inclined surfaces 31a and 31b serving as the crushing surface 31 is open, cutting chips are easily discharged to the outside.

FIG. 4 is a view showing a drill structure of a drilling machine according to a fourth embodiment of the present invention, wherein (a) is a bottom view and (b).
FIG. 2 is a sectional view taken along line DD of FIG.

The drill structure according to this embodiment has a segment 40a having a semicircular bottom surface and a segment 40 having a convex lens shape.
b and a drill. Segment 40a
And 40b are diamond segments like the segment 10 of the first embodiment.

In the case of this drill structure, the segment 40
The inclined surface 41 a formed on the surface a becomes the crushing surface 41, and the crushing surface 41 is in the diametric direction of the flat surface 2. The inclination angle of the inclined surface 41a is approximately 30 degrees with respect to the flat surface 2.

In the case of the drill structure of the present embodiment, the function of the segment 40a is substantially the same as that of the segment 10 of the first embodiment. In addition to this, the segment 40b is arranged, so that the drill balance is improved. The tip of the drilling machine is stabilized.

[0032]

According to the present invention, the following effects can be obtained.

(1) The tip of the rotating shaft of the drilling machine is a closed circular flat surface other than the fluid jet port, and one surface in a direction parallel to the diameter direction of this flat surface or two in the direction parallel to the radial direction.
Attaching a drill made of superabrasive grains with a crushing surface to the flat surface, and forming a sloping surface on the crushing surface in the direction in which the cross-sectional area at the tip of the segment decreases to reduce crushing of cuttings. The area that contributes is increased and crushing is promoted. Further, in addition to the small crushing of the cuttings, the crushing action surface is in a direction parallel to the diametrical direction or the radial direction of the flat surface, so that the discharge of the cuttings is improved.

(2) The shape of the segment constituting the drill may be a shape in which the bottom surface is substantially semicircular and the crushing surface in the direction parallel to the diameter direction is inclined, or the bottom shape is approximately 1/4 circular and the radius is The shape of the crushing surface in the direction parallel to the direction is inclined or the shape of the crushing surface in the direction parallel to the radial direction is approximately 3/4 circular and the shape of the crushing surface in the direction parallel to the radial direction is inclined. The facing side is greatly opened, and the cutting chips are easily discharged to the outside, and the clogging of the fluid ejection port is also prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a drill structure of a drilling machine according to a first embodiment.

FIG. 2 is a diagram showing a drill structure of a drilling machine according to a second embodiment.

FIG. 3 is a view showing a drill structure of a drilling machine according to a third embodiment.

FIG. 4 is a view showing a drill structure of a drilling machine according to a fourth embodiment.

FIG. 5 is a view showing an example of a drill structure of a conventional drilling machine.

FIG. 6 is a view showing an example of a drill structure of a conventional drilling machine.

FIG. 7 is a diagram showing an example of a drill structure of a conventional drilling machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Rotation axis 2 Flat surface 3 Cooling water ejection port 10, 20, 30a, 30b, 40a, 40b Segment 11, 21, 31, 41 Crushing surface 11a, 21a, 31a, 31b, 41a Inclined surface

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiya Ogata Noritake Diamond Co., Ltd. 210, Tanushimaru-cho, Ukiha-gun, Fukuoka Prefecture (72) Inventor Susumu Susumu 210, Takeno Daino, Tanushimaru-cho, Ukiha-gun, Fukuoka Noritake Dia Co., Ltd. (72) Inventor Yoji Niizawa 210 Takeno, Tanushimaru-cho, Ukiha-gun, Fukuoka Prefecture Noritake Diamond Co., Ltd.F-term (reference) 3C037 AA05 DD06 FF06 FF09 3C069 AA04 BA09 BB01 CA10 DA07

Claims (2)

[Claims] 1. A drill structure for a drilling machine, wherein a drill is attached to the tip of a hollow rotary shaft and a fluid supplied through a flow path inside the rotary shaft is jetted toward the tip of the drill to drill the drill. A superabrasive grain segment having a circular flat surface closed at its tip other than the fluid ejection port and having one crushing surface in a direction parallel to the diameter direction of the flat surface or two surfaces in a direction parallel to the radial direction of the flat surface. A drill structure for a drilling machine, characterized in that the drill is attached to the flat surface, and the crushing surface is formed with an inclined surface in a direction in which a cross-sectional area on the segment tip side decreases. 2. A shape of the segment, wherein the shape of the bottom surface is substantially semicircular and the crushing surface in the direction parallel to the diameter direction is inclined, or the shape of the bottom surface is substantially a quarter circle and parallel to the radial direction. Shape in which the crushing action surface in the direction has a slope,
2. A crushing surface in a direction parallel to a radial direction having an approximately 3/4 circular bottom surface and an inclined surface.
The drill structure of the drilling machine according to the above.