JP2010201733A - Drill bit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill bit capable of efficiently sucking dust without unnecessarily enlarging the diameter of dust suction hole. <P>SOLUTION: The drill bit 1 has a bit end part 3 and a bit shaft part 2, The bit end part 3 is equipped with three or more cutting edges arranged in the circumferential direction on its tip, and a cutting edge formed as a joining ridge line L1 between a rake face 3s and a flank 3e formed in each cutting edge part as its cutting blade, and the bit shaft part 2 is welded through its end face on a base end face of the bit end part 3 to allow an integrated rotation. The dust suction passage is formed in the longitudinal direction of the bit shaft part 2. The auxiliary dust suction passage 6 is formed in the upstream side of the dust suction passage in the state of forming an intersection angle to the longitudinal direction so that its tip may be exposed to the outer diameter side of each boundary of the bit end part 3 and its base end may communicate with the suction passage, wherein the rake face 3s and the flank 3e located ahead of it in rotational direction join at each boundary in bottom view. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drill bit for drilling a concrete or stone material, and more particularly to a drill bit suitable for drilling an anchor bolt hole.

  Conventionally, when drilling a concrete or stone material, a drill bit is used as a drilling tool.

Such drill bits may be used for drilling so-called “anchor bolt holes” in concrete surfaces.
Such an “anchor bolt hole” needs to remove as much as possible cutting chips and the like existing in the hole in order to obtain a predetermined strong pull-out force to the metal anchor bolt implanted in the hole. is there.
For this reason, a so-called “dust removal operation” is required after the drilling operation of the “anchor bolt hole”, by using a dust collector or the like to remove the cutting waste in the hole. That is, before the anchor bolt is implanted in the anchor bolt hole, it is required to remove as much as possible the cutting waste adhering to the hole.

Therefore, in the conventional case, after drilling with a drill bit, the tip of the cleaning nozzle whose base end is connected to the suction port of the suction device is inserted into the anchor bolt hole using a dust collector, and the cutting in the hole is performed. Scraps and other dust were removed by suction. As this type of dust collector, for example, there is a dust collector provided by the present applicant (Patent Document 1).
In addition, in order to collect chips and the like generated at the tip during the drilling operation at the same time as the drilling operation, a drill bit in which a dust suction hole is formed at the center of the drill bit tip may be used. The drill bit provided with such a dust suction hole has two cutting blade portions at the tip of the drill bit, that is, the cutting blade portions are arranged at an interval of 180 degrees. That is, in such a drill bit, a dust suction hole having a diameter larger than the width of the cutting blade portion is provided in the center of the bit shaft portion, and a part of the opening at the tip of the dust suction hole is provided between the cutting blade portion and the cutting blade portion. It had the form which faced the tip side from the part (patent document 2).

International publication WO2007 / 032084. Japanese Patent Publication No. 11-77662.

However, in the case of a drill bit having three or more cutting edge portions, the above configuration cannot be adopted. In other words, if the dust suction hole having a diameter large enough to expose the tip end of the dust suction hole partially or between the cutting blade part to the tip side is formed in the bit shaft part, the diameter of the bit shaft part There is a concern that the thickness in the direction becomes thin and the rigidity decreases. In particular, in the case of such a drill bit, since the drilling is performed by rotating while applying an impact force at an appropriate interval in the axial direction, a problem arises in strength when the thickness is reduced.
Further, in the case of a drill bit in which the bit shaft portion is integrally welded to the base end of the bit tip portion having the cutting edge portion at the tip, the diameter of the dust suction hole is simply and uniquely increased as described above. Then, there is a concern that the bonding area (welding area) between the bit tip portion and the bit shaft portion becomes small, the bonding strength is insufficient, and the long-term use cannot be endured.

  On the other hand, if the diameter of the dust suction hole is made small in order to solve the above problems, the exposed opening area to the tip of the dust suction hole is insufficient, and the dust suction effect is low.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a drill bit that solves the technical problems that contradict each other.

In the drill bit according to the present invention, at least three or more cutting blade portions are spaced apart from each other in the circumferential direction at the tip, and the joining ridge line between the rake face and the flank surface formed on each cutting blade portion serves as the cutting edge. In a drill bit having a bit tip portion of the form and a bit shaft portion having a tip surface welded so as to rotate integrally with the base end surface of the bit tip portion,
The bit shaft portion is provided with a dust suction passage extending in the longitudinal direction thereof,
The tip end of the bit has an opening on the outer diameter side of each boundary where the rake face and the flank face of the cutting edge located forward in the rotational direction in bottom view are joined, and the base end communicates with the dust suction passage. Therefore, the dust suction auxiliary passages formed so as to have an intersection angle with respect to the longitudinal direction are provided upstream of the suction of the dust suction passages of the bit shaft portion.

Thus, according to the drill bit configured as described above, the dust that has been drilled by the cutting edge portion to become cutting waste is located on the rake face of each cutting edge portion and in the front in the rotation direction thereof. From the opening at each end of the dust suction auxiliary passage formed between the flank faces of the cutting edge portion, the dust suction passage is sucked into the dust suction passage. In particular, since the opening of the dust suction auxiliary passage exists in front of the rake face of each cutting edge portion in the rotational direction, it is possible to effectively suck dust that has been scooped and scattered by the rake face. .
For this reason, dust such as concrete generated by cutting is efficiently sucked into the dust suction passage without diffusing outside from the drilled hole drilled by the drill bit. Therefore, if the base end side of the dust suction passage is connected to the suction port of the dust collector via a hose or the like, there will be almost no dust in the drilled hole after drilling, and therefore the state as it is after drilling is completed. It becomes possible to plant anchor bolts.

  Further, as described above, the tip of the dust suction auxiliary passage is provided so as to open to the outer diameter side of each boundary where the rake face and the flank face of the cutting edge portion positioned forward in the rotation direction join in the bottom view. Therefore, the base end surface of the bit front end portion and the front end surface of the bit shaft portion can be brought into contact with each other with a relatively large area. For this reason, the said bit front-end | tip part and a bit shaft part can take these welding surfaces large, As a result, it becomes possible to weld firmly.

  Further, in the drill bit, when the dust suction passage is configured to penetrate the tip end surface of the bit shaft portion with any appropriate area, the dust suction passage can be easily processed in the manufacturing process, and It is possible to obtain a configuration in which the contact area with the bit tip is moderately reduced. In such a case, a bonding method is adopted in which welding is performed by heat generated by electrical resistance generated at the contact portion of the two members to be connected. In this case, the contact area between the bit tip and the bit shaft can be appropriately reduced, so that the absolute pressure value for joining and clamping the two during electric welding can be lowered, and therefore the welding equipment with small capacity Thus, welding can be performed. Moreover, since the rotational torque acting between the bit tip portion and the bit shaft portion is received by the welded portion located in these outer diameter regions, as described above, even if the contact area between them is relatively small. The rotational torque transmission performance required for the joint portion can be obtained.

  Further, in the drill bit, when the base end surface of the bit tip portion and the tip surface of the bit shaft portion are both configured as flat surfaces, the bit tip portion and the bit shaft portion are both simple structures. It becomes easy to process at the time of manufacture.

  Further, in the drill bit, when the concave and convex portions are formed on the base end surface of the bit distal end portion and the concave and convex portions are formed on the distal end surface of the bit shaft portion, the bit distal end portion is formed. The contact area between the bit shaft portion and the bit shaft portion is increased, and the engagement of the projections and depressions allows the stress in the rotating direction (rotational torque) acting on the drill bit during drilling to be effectively received. For this reason, it becomes a structure which can endure a big rotational torque.

  According to the present invention configured as described above, a drill bit having three or more cutting blades at the tip exhibits high dust absorption performance at the tip of the drill bit and has excellent durability during drilling operations. And it becomes a drill bit which can transmit high rotational torque.

It is a perspective view which expands and shows the structure of the front-end | tip part of the drill bit concerning one Example of this invention. It is a perspective view which shows the whole structure of the drill bit which has a front-end | tip part shown in FIG. It is the expanded bottom view which expanded and showed the structure which looked at the drill bit shown in FIG. 1 from the bottom face direction (front-end | tip direction). It is the side view which carried out the cross-section and showed the front-end | tip part of the said drill bit which shows structures, such as a dust suction path inside a drill bit shown in FIG. 1, and a dust suction auxiliary path. It is a partial side view which shows the structure of the front-end | tip part of the bit shaft part of the drill bit shown in FIG. It is the VI-VI arrow line view of FIG. 5 which shows the structure seen from the bottom face direction of the bit shaft part shown in FIG. It is the figure which looked at the bit front-end | tip part of the drill bit shown in FIG. 1 from the bottom face side (front-end | tip direction). It is a perspective view which expands and shows the structure of the drill bit concerning the Example (Example 2) different from the Example shown in FIGS. It is an enlarged bottom view which shows the structure which looked at the drill bit shown in FIG. 8 from the bottom side (front end direction). It is the side view which carried out the cross-section and showed the front-end | tip part of the said drill bit which shows structures, such as a dust suction path inside a drill bit shown in FIG. 8, and a dust suction auxiliary path. It is a partial side view which shows the structure of the bit shaft part of the drill bit shown in FIG. It is the XII-XII arrow line view of FIG. 11 which shows the structure seen from the bottom face side of the bit shaft part shown in FIG. It is the figure which looked at the bit front-end | tip part of the drill bit shown in FIG. 8 from the bottom face side (front-end | tip direction). It is a figure which shows roughly the state currently drilled to to-be-punched objects, such as concrete, using the drill bit shown in FIGS. It is sectional drawing of this drill bit which represented the dust suction state of the drill bit of FIG. 14 with the dust to attract | suck with a small dot.

[Example]
Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings.

Example 1
As shown in FIG. 2, the drill bit 1 according to the present embodiment roughly includes a bit shaft portion 2 and a bit tip portion 3 provided integrally with the tip end portion thereof.

The bit shaft portion 2 includes a shank portion 2A having a regular octagonal cross section attached to a chuck portion 10c (see FIG. 14) of an electric drill apparatus 10 (see FIG. 14) at a proximal end portion, and a distal end thereof. The shaft main part 2B from which the cross section formed is circular and an outer diameter changes with parts is comprised.
The shaft main portion 2B includes a shaft distal end portion 2a having the same diameter extending from the distal end portion to a slightly proximal end, and a rotational support that is adjacent to the proximal end and has a slightly larger diameter than the shaft distal end portion 2a. The portion 2b and an extending portion 2c whose diameter changes depending on a portion adjacent to the proximal end of the portion 2b and integrally connected to the shank portion 2B.
The shank tip 2a has a dust suction passage 4 extending in the longitudinal direction X of the drill bit 1 (see the X arrow direction in FIG. 2), as shown in FIG. 4, at the center of the circular cross section. Yes.
As shown in FIG. 4, the base end of the dust suction passage 4 is connected to a dust suction connection passage 5 that penetrates a circular cross section formed in the rotation support portion 2b in the radial direction.
On the other hand, as shown in FIGS. 5 and 6, the tip of the dust suction passage 4 extends to the tip surface 2F of the bit shaft portion 2 and opens to the tip surface 2F. Further, as shown in FIG. 6, the outer side of the dust suction passage 4 that opens to the front end surface 2 </ b> F of the bit shaft portion 2 is separated from the dust suction passage 4 and surrounded from the periphery. A plurality of (in this embodiment, five in accordance with the number of cutting blade portions) openings at the tip of the dust suction auxiliary passage 6 are formed. As shown in FIG. 4 or FIG. 5, the dust suction auxiliary passage 6 is extended toward the dust suction passage 4 so as to have an angle of intersection with the longitudinal direction X. Each base end is connected to the dust suction passage 4.
Further, in this embodiment, as shown in FIGS. 5 and 6, a cylindrical outer peripheral wall 2r that protrudes toward the front end is formed on the front end surface 2F of the bit shaft portion 2 as shown in FIGS. The outer peripheral wall 2r has a notch 2d so as not to interfere with a portion that interferes with the cutting edge 3c (see FIGS. 1 and 3) formed on the bit tip 3. Are provided, and the overall shape is formed in a substantially crown shape.

As shown in FIG. 1, FIG. 3, or FIG. 7, the bit tip portion 3 has at least three or more cutting blade portions 3 c formed in the circumferential direction at the tip. In the case of this embodiment, the outer diameter portions of the five cutting blade portions 3c are spaced apart from each other in the circumferential direction, and a schematic form in a bottom view is formed in a “star shape”. Also, as shown in FIG. 3 or FIG. 7, the circumferential spacing between the respective cutting blade portions 3c is three of the five cutting blade portions 3c adjacent to each other with an interval of 90 degrees. Further, the four cutting edge portions 3c adjacent to each other (the cutting edge portion 3c located in the left half in FIG. 3) are arranged at an interval of 60 degrees.
Each cutting edge portion 3c includes a rake face 3s in front of the rotation direction R (see arrow R in FIG. 3) and a flank 3e behind the rotation direction R. A cutting edge is formed by the joining ridge line L1 between the rake face 3s and the flank face 3e of each cutting edge portion 3c.
Further, the inner diameter end of the cutting edge of each cutting edge portion 3 c is joined at the rotation center O <b> 1 of the drill bit 1 to form a pointed chisel point P.
As shown in FIG. 7, the bottom face view has a substantially triangular shape between the flank 3 e of the one cutting edge 3 c and the rake face 3 s of the cutting edge 3 c located rearward in the rotation direction. A gap 7 is formed. Therefore, in this embodiment, one gap 7 is formed between each of the five cutting blade portions 3c.
As shown in FIG. 3, at each position where the gap 7 is formed, that is, on the outer diameter side of the boundary between each flank 3e and the rake face 3s, the dust suction auxiliary passage 6 of the bit shaft portion 2 The tip is open. Exactly, most of the entire cross-sectional area of the dust suction auxiliary passage 6 (about 95% in this embodiment) is open to the gap 7.

  Further, the bit tip portion 4 is arranged with respect to the bit shaft portion 2 such that each cutting edge portion 3 c of the bit tip portion 4 is inserted into the notch 2 d of the bit shaft portion 2. That is, irregularities are formed by the notches 2d on the distal end surface 3F of the bit shaft portion 3 (in this embodiment, the outer peripheral wall portion 2r of the distal end surface 3F), and the base end surface of the bit distal end portion 4 (this embodiment) In FIG. 1, irregularities are formed on the bottom surface of the cutting edge portion 3 c by the cutting edge portion 3 c and the gap 7. As clearly shown in FIG. 1, each irregularity of the bit tip portion 4 and the bit shaft portion 2 is formed. Are complementary to each other, that is, in a state of meshing, the base end surface of the bit distal end portion 4 is integrally joined to the distal end surface of the bit shaft portion 2.

  And in this Example, the said joining is performed by the connection method (welding method) of the form with which both are welded by the heat_generation | fever by electrical resistance. Of course, instead of welding by electric resistance, other welding methods such as brazing welding may be used, or welding using laser light may be used. Alternatively, the joining may be performed with an adhesive.

  By the way, as shown in FIGS. 1 and 3, the reinforcing cutting edge portion 3k in which the rake angle and the relief angle at the outer diameter end portion and the tip end portion of the cutting edge portion 3c are obtuse compared to the inner diameter portion. Is formed so that the outer diameter end portion is not lost with respect to the impact during the drilling operation, and the durability is improved. An adjustment surface portion 3j having a rake angle and a relief angle that are more acute is formed adjacent to the reinforcing cutting edge surface 3k in the circumferential direction.

According to the drill bit 1 according to the present embodiment configured as described above, as shown in FIG. 14, the shank portion 2A is imparted with a vibration operation in rotation and axial direction (coincidence with the longitudinal direction). It is attached to the chuck portion 10c of the electric drill apparatus (vibration type electric drill apparatus) 10 that can be operated, and acts as follows when perforating an object to be drilled, for example, concrete. That means
As shown in FIG. 14, the suction port of the support holder 12 that is arranged on the rotation support portion 2 b of the drill bit 1 and does not rotate is connected to the suction port 13 a of the suction device 13 via the hose 14. The switch 10a of the drill device 10 is operated and turned on. By this operation, the electric drill device 10 gives the drill bit 1 a rotational operation and an axial vibration operation, and the drill bit 1 drills a drilled object. By this perforation, dust such as chips is generated in the perforated hole, and such dust is effectively sucked from the opening at the tip of the dust suction auxiliary passage 6. In particular, since there is an opening at the tip of the dust suction auxiliary passage 6 in front of the rotation direction R of the rake face 3s of each cutting edge portion 3c, dust or the like scooped by the rake face 3s is effectively sucked from the opening. can do. The suction of the dust and the like is performed by the suction action of the dust suction auxiliary passage 6. In the case of the first embodiment according to the present invention, when the dust or the like is sucked, the periphery of the front end surface 2F is surrounded by the cylindrical outer peripheral wall 2r. The cutting waste cut by the cutting edge portion 3 c is effectively sucked from the opening at the tip of the dust suction auxiliary passage 6.

  For this reason, as shown in FIG. 15, dust (dust) such as concrete generated in the drilling hole 16 by the drilling operation does not diffuse from the drilling hole 16 to the outside, and is absorbed from the dust suction auxiliary passage 6. The dust is efficiently sucked into the suction device 13 through the passage 4, the dust suction connection passage 5, and the hose 14.

  Accordingly, there is no dust or the like in the drilled hole 16 after drilling, and therefore it is possible to implant an anchor bolt (not shown) as it is after the drilling is completed.

(Example 2)
By the way, as a drill bit concerning this invention, it may replace with the said structure and the drill bit of a structure as illustrated in FIGS. 8-13 may be sufficient. That means
In the case of the drill bit 101 shown in FIGS. 8 to 13, the tip surface 102F of the bit shaft portion 102 is configured as a flat surface as shown in FIGS. The bit distal end portion 3 is joined in a state where the base end surface is flatly joined.
In other respects, since it has the same configuration as that of the first embodiment, the reference numeral added to the corresponding reference numeral of the first embodiment shown in FIGS. Detailed description of the drill bit according to the second embodiment shown in FIG.

  In the case of the drill bit 101 configured as described above, the basic operation is the same as that of the first embodiment described above, but the configuration of the tip portion of the bit shaft portion 102 is a plane. Therefore, the drill bit 101 can be simplified and is excellent in that the manufacturing of the drill bit 101 is easier.

  Also in the case of the drill bits 1 and 101 according to the first and second embodiments, as described above, the opening area of the dust suction passages 4 and 104 or the dust suction auxiliary passage 6 to the distal end surfaces 2F and 102F is adjusted. In other words, the opening area is adjusted to a predetermined area from a value close to zero to a predetermined size (specifically, the area at the base end of the dust suction passages 4, 104 or the dust suction auxiliary passages 6, 106). Accordingly, when manufacturing drill bits having different sizes, the pressing force per unit area required for welding by the electric resistance can be matched. In other words, when the pressing capability of the welding device by electric resistance is low, the joining area between the base end surface of the bit tip portion and the area of the tip surface of the bit shaft portion 2 is set to the tip surface of the bit shaft portion 2. By reducing the area, the necessary pressing force per unit area can be secured and welding can be performed properly.

  It goes without saying that the present invention is not limited to the contents described in the above embodiments, and can be implemented with various modifications without departing from the basic technical idea of the present invention.

  The drill bit according to the present invention can be used when drilling a drilling object such as concrete, stone, or tile.

DESCRIPTION OF SYMBOLS 1 ... Drill bit 2 ... Bit shaft part 2F ... Tip surface 3 ... Bit tip part 3c ... Cutting blade part 3e ... Flank 3s ... Rake face 4 ... Dust absorption passage 6 ... Dust absorption auxiliary passage L1 ... Joining ridge line X ... Longitudinal direction

Claims (4)

At least three or more cutting blade portions are arranged at the tip end in the circumferential direction, and the bit tip portion is configured so that the joining edge line of the rake face and the flank face formed on each cutting edge portion serves as a cutting edge. In a drill bit having a bit shaft portion with a distal end surface welded so as to rotate integrally with a base end surface of the bit distal end portion,
The bit shaft portion is provided with a dust suction passage extending in the longitudinal direction thereof,
The tip end of the bit has an opening on the outer diameter side of each boundary where the rake face and the flank face of the cutting edge located forward in the rotational direction in bottom view are joined, and the base end communicates with the dust suction passage. Therefore, a drill bit characterized in that dust suction auxiliary passages formed so as to have an intersection angle with respect to the longitudinal direction are provided upstream of suction of the dust suction passage of the bit shaft portion.   The drill bit according to claim 1, wherein the dust passage is made to penetrate the tip end surface of the bit shaft portion.   The drill bit according to claim 1 or 2, wherein a base end surface of the bit tip portion and a tip surface of the bit shaft portion are both flat surfaces.   The unevenness of the form which complemented the said unevenness was formed in the front end surface of the said bit shaft part while forming an unevenness | corrugation in the base end surface of the said bit front-end | tip part, It was set as the structure characterized by the above-mentioned. Drill bit.

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