Perforation method and perforation device

Abstract

To provide a drilling method and a drilling device capable of efficiently performing drilling.SOLUTION: A first tip part 30 comprises: plural tips 31 arranged so as to be separated at a circumferential face on a side of a drilling direction of a cylindrical body; and a center drill arranged at the center of the cylindrical body and having a tip part projected from the tips 31 in the drilling direction. Using a first core bit 25 fitted with the first tip part 30, while drilling a surface of a concrete member 10 by a drill blade part 37 of the center drill, a guide groove is formed. Thereafter, a second core bit fitted with the plural tips 31 arranged so as to be separated at the circumferential face on the side of the drilling direction of the cylindrical body is inserted into the guide groove to perform drilling.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drilling method and a drilling device for forming holes in concrete members or the like. [Background technology]

[0002] A drilling device equipped with a cylindrical core bit is known for drilling holes in structures such as concrete (see, for example, Patent Document 1). The drilling device described in this document moves the core bit in a straight line while rotating it to form a hole in the object to be drilled. Furthermore, this drilling device is equipped with a suction part that is disposed in the internal space of the shank of the core bit and has a suction port formed on the outer periphery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-177740 Summary of the Invention [Problem to be solved by the invention]

[0004] The distance from the core drill support to the tip of the bit where the cutting edge is located is long, and if the concrete material being drilled is hard, the tip of the core bit may vibrate due to centrifugal force when cutting into the concrete material, making it difficult to drill smoothly. [Means for solving the problem]

[0005] A drilling method that solves the above problem is a drilling method that uses a core drill equipped with a core bit to form a hole in an object to be drilled, in which a first core bit equipped with a first tip portion that includes a plurality of first tips arranged on the circumference of a cylindrical body on the drilling direction side and a center drill that is arranged at the center of the cylindrical body and has a tip that protrudes from the first tip in the drilling direction is used to drill the surface of the object to be drilled with the center drill, forming a guide groove, and a second core bit equipped with a plurality of second tips arranged on the circumference of the cylindrical body on the drilling direction side is inserted into the guide groove to drill.

[0006] Furthermore, a drilling device that solves the above problem is a drilling device that drills an object to be drilled using a core drill equipped with a core bit, wherein the core bit comprises a plurality of first tips arranged on the circumference of a cylindrical body on the drilling direction side, and a center drill arranged at the center of the cylindrical body and having a tip protruding from the first tip in the drilling direction, and is capable of being attached by replacing a first tip portion that forms a guide groove while drilling the surface of the object to be drilled with the center drill, and a second tip portion that can be placed in the guide groove and has a plurality of second tips arranged on the circumference of the cylindrical body on the drilling direction side. In addition, a drilling device that solves the above problem is a drilling device that drills an object to be drilled using a core drill equipped with a core bit, and is equipped with a first core bit that is equipped with a first tip section that has a plurality of first tips arranged on the circumference of a cylindrical body on the drilling direction side and a center drill that is arranged at the center of the cylindrical body and has a tip that protrudes from the first tip in the drilling direction, and that forms a guide groove while drilling the surface of the object to be drilled with the center drill, and a second core bit that is equipped with a second tip section that can be placed in the guide groove and has a plurality of second tips arranged on the circumference of the cylindrical body on the drilling direction side, and that inserts the second tips into the guide groove to drill. [Effects of the Invention]

[0007] According to the present invention, efficient drilling can be achieved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a front view showing drilling by a first core drill of the drilling device of the embodiment. FIG. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view showing the structure of the tip of the first core drill of the embodiment. [Figure 3] FIG. 2 is an enlarged perspective view of a center drill of the first core drill of the embodiment. [Figure 4] FIG. 2 is an explanatory view illustrating a state before drilling using a first core drill of the embodiment. [Figure 5] FIG. 10 is an explanatory view illustrating a state in which a hole is being drilled by a center drill of the first core drill of the embodiment. [Figure 6] 10 is an explanatory view illustrating a guide groove formed by drilling using a first core drill of the embodiment. FIG. [Figure 7] 10 is an explanatory view illustrating a state in which the tip of a second core drill of the drilling device of the embodiment is placed in a guide groove. FIG. [Figure 8] FIG. 10 is an explanatory view illustrating the state in which concrete has been drilled using the second core drill of the embodiment. [Figure 9] FIG. 10 is an enlarged perspective view of a center drill of a first core drill in a first modified example. [Figure 10] FIG. 10 is an explanatory diagram illustrating a configuration in which air injection nozzles are provided around the center drill of the first core drill in the second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a drilling method and a drilling device will be described below with reference to Figures 1 to 8. In this embodiment, a drilling method and a drilling device will be described for forming a cylindrical hole in a concrete block that constitutes a reactor building (primary shielding wall). In this embodiment, a core drill 20 as the drilling device performs drilling by replacing two different types of first and second tip parts. The core drill 20 with the first tip part attached will be referred to as the first core drill, and the core drill 20 with the second tip part attached will be referred to as the second core drill.

[0010] In this embodiment, as shown in FIG. 1 , the core drill 20 includes a pole base 21, a pole 22, a drill head 23, and a core bit 25. The pole base 21 is fixed to the upper surface of a mounting plate 15. The mounting plate 15 is a plate made of metal such as iron and placed above the concrete member 10 to be drilled. A pole 22 is erected on the pole base 21. A pinion (not shown) of a slide block 23s of the drill head 23 is engaged with a rack (not shown) of the pole 22. By moving the slide block 23s in the extension direction of the pole 22, the drill head 23 can move straight in the drilling direction (downward in FIG. 1 ). The drill head 23 has a built-in motor. Hereinafter, the side facing the drill head 23 will be referred to as the base end, and the opposite side (the drilling direction side) will be referred to as the tip end. The torque of the motor rotates a core bit 25 provided at the tip of the drill head 23.

[0011] The core bit 25 has a generally cylindrical shape with a closed base end. A suction device (not shown) is connected to the base end of the core bit 25 via a discharge pipe. This suction device sucks up chips generated during drilling and discharges them from the core bit 25 to the outside.

[0012] The core bit 25 includes an attachment portion 25a, a cylindrical portion 25t, and a first tip portion 30. The attachment portion 25a is formed at the center of the closed surface on the base end side of the core bit 25, protruding toward the base end side. The attachment portion 25a is attached to the rotation shaft of the motor of the drill head 23. The cylindrical portion 25t is fixed integrally to the attachment portion 25a. In this embodiment, the length L1 of the cylindrical portion 25t is 4 m to 6 m.

[0013] 2, a first tip portion 30 is provided on the tip side of the core bit 25. Specifically, the cylindrical portion 25t of the core bit 25 and the first tip portion 30 are screwed together, and the outer peripheral surface of the cylindrical portion 25t and the outer peripheral surface of the first tip portion 30 are flush with each other.

[0014] (Configuration of first tip portion 30) The first tip portion 30 has a substantially cylindrical shape and can be removed from the tubular portion 25t of the core bit 25 and replaced. A plurality of tips 31 are provided at intervals on the underside (circumferentially) of the tip of the cylindrical body of the first tip portion 30. In this embodiment, each tip 31 is a diamond tip made by sintering synthetic diamond with metal, and has a columnar shape with an arc cross section. Each tip 31 is formed by radially stacking and integrally joining a first cutting edge portion and a second cutting edge portion of the same thickness. The second cutting edge portion is located on the outer periphery of the first cutting edge portion. The cutting edge of the first cutting edge portion is configured to protrude further toward the tip than the second cutting edge portion.

[0015] A circular mounting plate 32 is fixed to the base end of the first tip portion 30. A plurality of discharge holes 32h are formed and arranged in the mounting plate 32. Chips in the first tip portion 30 are discharged through the discharge holes 32h into the cylindrical portion 25t.

[0016] A center drill 35 is fixed to the mounting plate 32 by a plurality of fasteners (not shown), such as screws. The center drill 35 includes a support portion 36 and a drill cutting portion 37. A support portion 36 of the center drill 35 protrudes toward the tip side from the mounting plate 32. The support portion 36 supports a drill cutting edge portion 37 that protrudes toward the tip side.

[0017] 3, the support part 36 is a thick cylindrical block with a central through-hole 36h formed therein. The base end of the drill bit part 37 is inserted into the through-hole 36h and welded to the block.

[0018] As shown in FIG. 2, the support portion 36 supports the drill bit portion 37 so that the length DL1 of the drill bit portion 37 protruding from the tip of the support portion 36 is 70 mm or less. The drill bit portion 37 is positioned so that the central axis of the drill bit portion 37 coincides with the central axis C1 of the first tip portion 30. The drill bit portion 37 of this embodiment has multiple spirally formed blades, with grooves 37g formed between them. For example, a commercially available carbide drill with a diameter of 20 mm or more, such as that used in impact (hammer) drills, is used as the drill bit portion 37. Here, the drill bit portion 37 has a diameter D1 of 24 mm. In this embodiment, the length DL1 of the drill bit portion 37 is determined depending on the depth of the guide groove to be formed. Here, the length DL1 is, for example, approximately 63 mm. The tip of the drill bit portion 37 protrudes distally from the tip of the tip 31 by a length h1 (approximately 10 mm).

[0019] (Second tip portion 40) 7, the second tip portion 40 is attached to the tip of the core bit 25 of the core drill 20 of this embodiment when in use. The first tip portion 30 attached to the tip of the core bit 25 is removed, and the second tip portion 40 is attached by screwing it in place of the first tip portion 30. When attached, the outer peripheral surface of the second tip portion 40 is flush with the outer peripheral surface of the cylindrical portion 25t.

[0020] The second tip section 40 has the same configuration as the first tip section 30, with the mounting plate 32 and center drill 35 removed. Specifically, the second tip section 40 has a cylindrical body with the same diameter as the first tip section 30, and is provided with a plurality of spaced apart tips 31 at the tip of the cylindrical body.

[0021] (Drilling method) Next, a drilling method for forming a through hole in the concrete member 10 using the above-described core drill 20 will be described with reference to FIGS.

[0022] First, the core drill 20 with the first tip portion 30 attached to its tip is placed above the concrete member 10 in which a through hole is to be formed. In this case, as shown in FIG. 4, the first tip portion 30 is placed directly above the upper surface (surface) of the concrete member 10 at a position where a hole is to be formed.

[0023] Then, the core drill 20 is lowered while being rotated, and the suction device is driven in this case. 5, the tip of the drill bit portion 37 of the first tip portion 30 first comes into contact with the concrete member 10. In this case, the drill bit portion 37 drills a hole in the concrete member 10. The chips of the cut concrete member 10 are discharged to the suction device through the groove 37g of the drill bit portion 37, the discharge hole 32h of the mounting plate 32, the cylindrical portion 25t, and the discharge pipe.

[0024] Then, as the drill bit portion 37 drills the concrete member 10, the center position of the first tip portion 30 relative to the concrete member 10 is fixed. With the center position of the first tip portion 30 fixed by the drill cutting portion 37 in this manner, the core drill 20 is lowered so that the multiple tips 31 of the first tip portion 30 drill holes in the concrete member 10. Then, as shown in FIG. 1, tip 31 of first tip portion 30 drills a hole from the surface of concrete member 10 to a depth of about 25 to 60 mm (for example, 40 mm).

[0025] Next, the rotation of the core drill 20 is stopped and the core drill 20 is pulled upward. In this case, as shown in FIG. 6, a substantially cylindrical hole Gh1 formed by the center drill 35 and a substantially ring-shaped guide groove Gt1 formed by the tip 31 are formed in the concrete member 10.

[0026] Next, the first tip portion 30 at the tip of the core bit 25 of the core drill 20 is replaced with the second tip portion 40 . Next, as shown in FIG. 7, the core drill 20 is lowered and the tip 31 at the tip of the second tip portion 40 is inserted into the guide groove Gt1.

[0027] Next, while the suction device is being driven, the core drill 20 is lowered while being rotated, whereby the core drill 20 is used to drill a hole deeper than the guide groove Gt1. 8, the core bit 25 is then penetrated into the concrete member 10. Thereafter, the core drill 20 is pulled up, forming a cylindrical through-hole in the concrete member 10.

[0028] (action) A core drill 20 equipped with a first tip portion 30 having a protruding center drill 35 is used to drill a concrete member 10. As a result, before drilling with the first tip portion 30, the center position of the first tip portion 30 is positioned and held in the concrete member 10 by the drilling of the drill bit portion 37 of the center drill 35. In this state, drilling is performed with the tip 31 of the first tip portion 30, so vibration of the core bit 25 is suppressed and the guide groove Gt1 can be formed efficiently.

[0029] According to this embodiment, the following effects can be obtained. (1) In this embodiment, after the first tip portion 30 is drilled into the concrete member 10 by the center drill 35, the guide groove Gt1 is formed by the tip 31 of the first tip portion 30. As a result, when drilling with the tip 31, it is positioned by the drill cutting portion 37 of the center drill 35, so the desired guide groove Gt1 can be formed. Then, the tip 31 of the second tip portion 40 is inserted into this guide groove Gt1 to drill the hole, so even if the core bit 25 has a long cylindrical portion 25t, it can drill the hole smoothly at the correct position.

[0030] (2) In this embodiment, the center drill 35 has the drill bit portion 37 welded and fixed to the tip of the support portion 36, which is fixed to the mounting plate 32 welded to the first tip portion 30. This allows the length DL1 of the drill bit portion 37 from the fixed support portion 36 to be shortened, so that bending deformation of the drill bit portion 37 can be suppressed even if the concrete member 10 is hard.

[0031] (3) In this embodiment, the drill cutting edge portion 37 of the center drill 35 has a plurality of spiral blades with grooves 37g between them. This allows chips generated by drilling to be moved along each groove 37g from the cutting edge to the base end and discharged.

[0032] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. In the above embodiment, the first tip portion 30 that forms the guide groove Gt1 includes a drill cutting edge portion 37 having a spiral cutting edge and groove 37g. The center drill is not limited to having a spiral cutting edge and groove 37g, and may have a center that is aligned with the central axis of the core bit 25 and has a tip that protrudes from the tip of the tip 31.

[0033] For example, a center drill 55 shown in FIG. 9 may be fixed to the mounting plate 32 of the first tip portion 30. This center drill 55 has a support portion 36 and a drill blade portion 57. The drill blade portion 57 has a plurality of blades 57b arranged radially outward from the center at its tip. Furthermore, discharge holes 57h are provided between the blades 57b to discharge chips generated during drilling. In this center drill 55, the drill blade portion 57 is fixed via the support portion 36, so the length from the support portion 36 to the tip of the drill blade portion 57 can be shortened, thereby suppressing bending deformation of the drill blade portion 57.

[0034] In the above embodiment, chips generated during drilling are discharged from the core bit 25 using a suction device connected to the base end of the core bit 25 via an exhaust pipe. In addition, an air injection unit may be provided at the center nozzle of the core bit 25 to blow away chips adhering thereto.

[0035] For example, as shown in FIG. 10 , a center nozzle 61 has a stepped support portion 62 and a drill bit portion 37. A nozzle 63 is provided on the large-diameter portion of the support portion 62. The tip of the nozzle 63 is directed toward the tip of the drill bit portion 37. The support portion 62 is fixed to the third tip portion 60 via the mounting plate 32. A mounting member 64 that supplies air to the nozzle 63 is provided in the center of the mounting plate 32. A hose 65 connected to an air supply device is connected to the mounting member 64. When drilling with the drill bit portion 37 of the center nozzle 61, air is sprayed from the air supply device through the hose 65, mounting member 64, support portion 62, and nozzle 63 toward the tip of the drill bit portion 37. This allows drilling to be performed while blowing away chips adhering to the drill bit portion 37.

[0036] In the above embodiment, the first tip portion 30 that forms the guide groove Gt1 and the second tip portion 40 that is disposed in the guide groove Gt1 and performs drilling are provided as replacements for the core bit 25. The first core drill, which includes a first core bit with the first tip portion 30 attached, and the second core drill, which includes a second core bit with the second tip portion 40 attached, may be configured as separate components. In this case, a moving mechanism is provided to move the first and second core drills so that the second tip portion of the second core drill is positioned in the guide groove. After the first core drill forms the guide groove, the moving mechanism moves the first and second core drills. Next, the moving mechanism is used to position the second tip portion of the second core drill in the guide groove, and the second core drill is then operated to drill. Therefore, while the second core drill is drilling a hole, the first core drill can form a guide groove in another location, allowing holes to be drilled continuously.

[0037] In the above embodiment, the second tip portion 40 has the same shape as the first tip portion 30, excluding the mounting plate 32 and the center drill 35, which form the guide groove Gt1. The tip 31 of the second tip portion 40 that performs drilling does not have to have the same shape as the tip 31 of the first tip portion 30, as long as it has a shape that allows it to be placed in the guide groove Gt1. For example, it may have the same diameter as the tip 31 of the first tip portion 30, but a thinner blade thickness.

[0038] In the above embodiment, the core drill 20 is placed above the concrete member 10, and a hole is formed from the top surface of the concrete member 10. Drilling using a core drill is not limited to forming a through hole from the top surface, and may also form a through hole in the horizontal direction from the side of the concrete, for example.

[0039] In the above embodiment, the concrete member 10 is drilled using the long core bit 25. The object to be drilled is not limited to the concrete member 10, and the long core bit can be used to drill other hard materials such as metal blocks.

[0040] Next, the technical ideas that can be understood from the above-described embodiment and other examples will be described below. (a) A drilling device as described in any one of claims 2 to 5, characterized in that the second core bit has a tip of the same shape and size as the tip of the first core bit and drills a hole of the same diameter as the guide groove.

[0041] (b) A drilling device as described in any one of claims 2 to 5 or (a), characterized in that the first core bit and the second core bit are provided with bits having multiple blade portions of different lengths arranged radially. [Explanation of symbols]

[0042] C1...center axis, D1...diameter, L1, DL1, h1...length, Gh1...hole, Gt1...guide groove, 10...concrete member, 15, 32...mounting plate, 20...core drill, 21...pole base, 22...pole, 23...drill head, 23s...slide block, 25...core bit, 25a...mounting portion, 25t...cylindrical portion, 30...first tip portion, 31...tip, 32h, 57h...discharge hole, 35, 55...center drill, 36, 62...support portion, 36h...through hole, 37, 57...drill bit portion, 37g...groove, 40...second tip portion, 60...third tip portion, 61...center nozzle, 63...nozzle, 64...mounting member, 65...hose.

Claims

1. A drilling device that drills a drilling object using a core drill equipped with a core bit, The core bit is a first tip portion including a plurality of first tips arranged on a circumference of a cylindrical body on the drilling direction side, and a center drill arranged at the center of the cylindrical body and having a tip protruding from the first tip in the drilling direction, the first tip portion forming a guide groove while drilling the surface of the drilling object with the center drill; a second tip portion that can be placed in the guide groove and that includes a plurality of second tips that are arranged on a circumference of the cylindrical body in the drilling direction, and that can be attached by replacing the second tip portion; The center drill includes a support portion fixed to a mounting plate provided inside the cylindrical body of the first tip portion and having a discharge hole formed therein, the support portion protruding toward the tip end, and a drill cutting edge portion fixed to the support portion, The drill further includes a suction device that sucks chips cut by the drill blade portion through the discharge hole, A nozzle is provided inside the cylindrical body of the first tip portion, with its tip pointing toward the tip of the drill bit portion, A drilling device characterized in that air is sprayed from an air supply device to the tip of the drill bit through the nozzle.

2. A drilling device that drills a drilling object using a core drill equipped with a core bit, a first core bit equipped with a first tip portion including a plurality of first tips arranged on the circumference of a cylindrical body in the drilling direction and a center drill arranged at the center of the cylindrical body and having a tip protruding from the first tip in the drilling direction, and which forms a guide groove while drilling the surface of the drilling object with the center drill; a second core bit that can be placed in the guide groove and has a second tip portion attached thereto, the second tip portion having a plurality of second tips arranged on a circumference of a cylindrical body in a drilling direction, and that drills holes by inserting the second tips into the guide groove; The center drill includes a support portion fixed to a mounting plate provided inside the cylindrical body of the first tip portion and having a discharge hole formed therein, the support portion protruding toward the tip end, and a drill cutting edge portion fixed to the support portion, The drill further includes a suction device that sucks chips cut by the drill blade portion through the discharge hole, A nozzle is provided inside the cylindrical body of the first tip portion, with its tip pointing toward the tip of the drill bit portion, A drilling device characterized in that air is sprayed from an air supply device to the tip of the drill bit through the nozzle.

3. The apparatus further includes a moving mechanism for holding a first core drill provided with the first core bit and a second core drill provided with the second core bit, The drilling device according to claim 2 , wherein the moving mechanism positions the tip of the second core bit in the guide groove drilled by the first core bit.

4. A drilling method for forming a hole in a drilling object using a core drill equipped with a core bit, a first core bit equipped with a first tip portion including a plurality of first tips arranged on the circumference of a cylindrical body in the drilling direction, a support portion fixed to a mounting plate provided inside the cylindrical body and having a discharge hole formed therein and protruding toward the tip end, and a drill blade portion fixed to the support portion, and a center drill arranged in the center of the cylindrical body and having a tip protruding from the first tip in the drilling direction, and a guide groove is formed by drilling the surface of the object to be drilled with the center drill while sucking chips cut out by the drill blade portion with a suction device through the discharge hole; a second core bit having a plurality of second tips attached thereto and arranged on a circumference of the cylindrical body in the drilling direction is inserted into the guide groove to drill a hole; A drilling method characterized in that, during the drilling, air is sprayed from an air supply device onto the tip of the drill bit portion through a nozzle provided inside the cylindrical body of the first tip portion and directed toward the tip of the drill bit portion.

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