Radio detonator and antenna for radio detonator

Abstract

To provide a compact antenna with high transmission and reception efficiency for low-frequency radio signals, which have good permeability through bedrock, on a radio detonator.SOLUTION: A radio detonator 10 has an antenna 20 that transmits and receives radio signals and receives driving energy via a radio method. The radio detonator 10 has an operating capacitor 12e that stores energy received by the antenna 20 and a detonation capacitor 12f. The radio detonator 10 has an electric detonator 15 that detonates using electricity from the detonation capacitor 12f. The antenna 20 has a first coil 21, which is electrically connected to a receiving circuit, a transmitting circuit, and the operating capacitor 12e, and is wound with a first number of turns. The antenna 20 has a second coil 22, which is provided adjacent to and substantially coaxially with the first coil 21 and is wound with a second number of turns greater than the first number of turns. The antenna 20 has a resonant capacitor 23 electrically connected to the second coil 22.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a wireless detonator provided in a wireless detonation system used at sites such as tunnel excavation sites, rock crushing sites, and building structure crushing sites, and also to an antenna for the wireless detonator provided in the wireless detonator. [Background technology]

[0002] Wireless detonators are used in blasting work, for example, at tunnel excavation sites. Multiple charge holes are formed in the face of the tunnel to be blasted. The charge holes are, for example, roughly circular openings with a diameter of a few centimeters and a depth of several meters. A wireless detonator is inserted into the back of the charge hole, and an explosive is inserted in front of the wireless detonator. A blasting device is installed in a remote location away from the face. The blasting device transmits a detonation signal to the wireless detonator in the charge hole. This ignites the electric detonator of the wireless detonator, detonating the explosive.

[0003] As described in Patent Document 1, a conventional wireless detonation system has a large loop-shaped antenna. The antenna is installed near the face and shaped to follow the outer periphery of the face. A large amount of power is sent to the antenna via a wire from a large power source installed in a remote location away from the face. The antenna wirelessly charges the wireless detonator inside the face from the outside of the face. The antenna receives response signals and the like wirelessly transmitted from the wireless detonator inside the face to the outside of the face. The antenna wirelessly transmits detonation signals and the like from the outside of the face to the wireless detonator inside the face.

[0004] The wireless detonator described in Patent Document 1 is loaded into the charge hole in various positions relative to the large loop antenna. To enable transmission and reception regardless of the positional relationship, the wireless detonator is equipped with three coils with different axial directions as an antenna. To improve the antenna's power receiving efficiency, it is desirable to make the coils larger. The provision of a three-axis coil further increases the antenna's size. Therefore, depending on the condition of the inner wall of the charge hole, it may not be possible to load the detonator or it may become clogged midway. In addition, a receiving circuit must be provided for each of the three coils. Therefore, the power consumed by the three receiving circuits must be charged. Depending on the positional relationship between the three-axis coil and the large loop antenna, the charger for the wireless detonator may not be fully charged.

[0005] Furthermore, antennas consisting of three-axis coils have insufficient transmission efficiency, especially at lower frequencies. Even if the same structure were used to compensate for the transmission efficiency, it would be necessary to increase the charging capacity of the detonator charger to increase output. This would increase the charging time. It is preferable for wireless detonators and antennas to receive power or transmit and receive radio signals at low frequencies to improve rock penetration. Therefore, it is desirable to increase the transmission efficiency of wireless detonator antennas at low frequencies. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-087673 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, it is necessary to provide a small antenna on the wireless detonator that has high transmission and reception efficiency for low-frequency wireless signals that have good rock penetration. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, a wireless detonator has an antenna that transmits and receives wireless signals and receives driving energy wirelessly. The wireless detonator has a capacitor that stores the energy received by the antenna. The wireless detonator has an electric detonator that detonates with electricity from the capacitor. The antenna has a first coil that is electrically connected to the receiving circuit, the transmitting circuit, and the capacitor and is wound with a first number of turns. The antenna has a second coil that is disposed adjacent to the first coil and approximately coaxial with the first coil and is wound with a second number of turns that is greater than the first number of turns. The antenna has a resonance capacitor that is electrically connected to the second coil.

[0009] Therefore, the second coil, electrically connected to the resonant capacitor, resonates at a predetermined frequency. This allows the second coil to efficiently transmit and receive signals at the resonant frequency wirelessly. Furthermore, the impedance can be suppressed by reducing the number of turns in the first coil. The second coil can have a larger number of turns because its impedance is reduced by resonating with the resonant capacitor. When the second coil receives a wireless signal, current flows in the second coil, generating a magnetic field. This causes current to flow in the first coil, which transmits the signal to the first coil. When the first coil transmits a signal, current flows in the first coil, generating a magnetic field. This causes current to flow in the second coil, which then transmits the wireless signal. Thus, the small antenna of the wireless detonator can increase the efficiency of transmitting and receiving wireless signals.

[0010] According to another feature of the present disclosure, the first coil and the second coil have a diameter that can be inserted into a charge hole provided in the working face. Therefore, when the wireless detonator is loaded into the charge hole, it is possible to prevent the antenna having the first coil and the second coil from interfering with the inner wall of the charge hole. Therefore, the wireless detonator can be loaded into the charge hole smoothly.

[0011] According to another feature of the present disclosure, the antenna transmits and receives wireless signals in the range of 1 kHz to 500 kHz, so that the antenna of the wireless detonator in the charge hole can transmit and receive signals with a relay device or the like interposed between the detonator and the antenna and the detonator at a frequency that has high rock penetration.

[0012] According to another feature of the present disclosure, the first coil and the second coil have a diameter of 15 mm to 30 mm. The first number of turns is 3 to 15. The second number of turns is 30 to 200. Therefore, the antenna of the wireless detonator can be provided with a size that allows efficient transmission and reception and is easy to insert into the charge hole. Moreover, the first coil can be provided with a number of turns that can effectively suppress impedance. The second coil can be provided with a number of turns that allows efficient transmission and reception of wireless signals.

[0013] According to another feature of the present disclosure, a wireless detonator has a core made of an insulating material. The wireless detonator has a magnetic sheet wound around the outer periphery of the core. A first coil and a second coil are wound around the outer periphery of the magnetic sheet. Therefore, by using a lightweight core on the inner periphery of the magnetic sheet, the wireless detonator can be made lighter. Furthermore, the highly flexible magnetic sheet is less likely to break. This improves the workability of transporting and loading the wireless detonator.

[0014] According to another feature of the present disclosure, the wireless detonator includes a circuit board having a receiving circuit, a transmitting circuit, a capacitor, and a resonance capacitor. The circuit board is located close to the first coil and far from the second coil. Therefore, the second coil, which generates a stronger electric field when transmitting and receiving electromagnetic waves, is located farther from the circuit board. This reduces the effect of the electric field on the electronic circuit on the circuit board.

[0015] According to another feature of the present disclosure, the resonant capacitor includes a fixed capacitor and a variable capacitor. Therefore, the inductance of the second coil of each wireless detonator varies. The variable capacitor can adjust the variation in the inductance of the second coil, allowing the second coil to transmit and receive signals at a suitable resonant frequency.

[0016] According to another feature of the present disclosure, the wireless detonator has a main body tube. The main body tube houses an antenna, a capacitor, and an electric detonator. This allows the wireless detonator to be compact and easy to transport. Furthermore, by making the main body tube large enough to be easily loaded into the charge hole, the workability of loading the wireless detonator can be improved.

[0017] Another feature of the present disclosure relates to an antenna for a wireless detonator, which is used in a wireless detonator to transmit and receive wireless signals and to receive driving energy wirelessly. The antenna for a wireless detonator has a first coil, a second coil, and a resonance capacitor. Therefore, by providing a first coil with reduced impedance and a second coil electrically connected to the resonance capacitor, an antenna for a wireless detonator with high transmission and reception efficiency can be provided. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram of the overall configuration of the wireless detonation system of the present disclosure and a tunnel excavation site. [Figure 2] FIG. 1 is a schematic diagram of a radio detonator, a repeater device and a blaster inserted into a hole in the face. [Figure 3] FIG. 1 is a schematic diagram of a wireless detonator. [Figure 4] FIG. 2 is an exploded perspective view of an antenna for a wireless detonator. [Figure 5] FIG. 1 is a block diagram of a wireless detonator. [Figure 6] FIG. 1 is a schematic diagram showing a power supply device and a wireless detonator being charged. [Figure 7] 10 is a flowchart showing the charging process of the wireless detonator. [Figure 8] 10 is a flowchart showing a wireless signal receiving process and a wireless signal transmitting process of a wireless detonator. DETAILED DESCRIPTION OF THE INVENTION

[0019] One embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. The same reference numerals throughout the description refer to the same elements with the same functions, although the description will not be repeated. A wireless detonation system 1 is used to detonate an explosive 2 to excavate or crush structures such as tunnels, the seabed, rocks, and buildings. In this embodiment, an excavation site of a tunnel 40 will be described as an example, as shown in FIG. 1. The tunnel 40 has a vertically extending face 41 at its rear. A plurality of charge holes 41a are provided in the face 41 at predetermined intervals in the vertical and horizontal directions. The charge holes 41a extend linearly perpendicular to the face 41. The charge holes 41a are, for example, circular, with a diameter of 30 to 100 mm, and are drilled to a depth of several meters.

[0020] As shown in Figures 1 and 2, each charging hole 41a is loaded with a cylindrical wireless detonator 10 and multiple cylindrical explosives 2. The wireless detonator 10 is loaded at the back of the charging hole 41a with the electric detonator 15 facing forward. The multiple explosives 2 are loaded forward of the wireless detonator 10. The innermost explosive 2 adjacent to the wireless detonator 10 is the parent die 2a into which the electric detonator 15 is inserted. The parent die 2a is ignited by the electric detonator 15 to detonate. Multiple booster dies 2b are arranged along the charging hole 41a forward of the parent die 2a. The multiple booster dies 2b detonate in a chain reaction when the parent die 2a is detonated. The entrance of the charging hole 41a forward of the explosives 2 is sealed with a sealing member 41c such as clay.

[0021] 1 and 2, an insertion hole 41b is provided in the center of the working face 41, into which the main body 31 of the relay device 30 (described later) is inserted. The insertion hole 41b extends linearly along the direction perpendicular to the working face 41. The insertion hole 41b is, for example, circular and has a diameter of 30 mm to 100 mm, and is drilled to a depth of 100 mm to 500 mm. It is desirable to provide the insertion hole 41b at a position close to the ground in the center of the working face 41, where the distances to the charging holes 41a located at the left end, right end, and top end are approximately the same.

[0022] As shown in Figures 1 and 2, the wireless detonation system 1 has a blasting machine 3 that transmits detonation signals and the like and receives response signals and the like. The blasting machine 3 is used at a position sufficiently distant, for example, about 100 to 1000 m from the working face 41. The blasting machine 3 has an antenna 3a that transmits and receives radio signals, for example, in the UHF band (300 MHz to 3 GHz). The blasting machine 3 has an input unit 3b that can be operated to send radio signals. The blasting machine 3 has an output unit 3c that can display information received by the antenna 3a.

[0023] As shown in Figures 2, 3, and 5, the wireless detonator 10 has a cylindrical main body tube 11. The main body tube 11 is provided with a diameter smaller than the diameter of the charge hole 41a. The main body tube 11 is composed of a bottom portion 11a and a cover portion 11b that can be assembled together. The main body tube 11 accommodates a circuit board 12, an electric detonator 15, and an antenna (antenna for the wireless detonator) 20. A small-diameter electric detonator housing portion 11c into which the electric detonator 15 is inserted is provided at the tip of the cover portion 11b.

[0024] As shown in Figure 5, the circuit board 12 is provided with a CPU serving as a control circuit 12a that controls the operation of each component of the wireless detonator 10. The circuit board 12 is provided with a changeover switch 12b that is electrically connected to a first coil 21 of the antenna 20, which will be described later. The changeover switch 12b switches the circuit depending on whether the antenna 20 is receiving electrical energy or transmitting and receiving a wireless signal. The circuit board 12 is provided with a charging circuit 12c that is electrically connected to the changeover switch 12b, a receiving circuit 13, and a transmitting circuit 14. The receiving circuit 13 detects the analog signal received by the antenna 20 and outputs it as a digital signal to the control circuit 12a. The transmitting circuit 14 modulates the digital signal output from the control circuit 12a into an analog signal and outputs it to the antenna 20.

[0025] As shown in Fig. 5, the circuit board 12 is provided with a power supply circuit 12d including an operating capacitor 12e. The operating capacitor 12e stores electrical energy for operating each circuit on the circuit board 12 and also temporarily stores electrical energy for igniting the electric detonator 15. The operating capacitor 12e corresponds to the capacitor in this disclosure. The power supply circuit 12d is electrically connected to the control circuit 12a, the charging circuit 12c, the detonation capacitor 12f, the transmission circuit 14, etc.

[0026] As shown in FIG. 5, the circuit board 12 is provided with an initiating capacitor 12f. The initiating capacitor 12f stores electrical energy for igniting the electric detonator 15 and corresponds to the capacitor in this disclosure. The initiating capacitor 12f is provided downstream of the operating capacitor 12e and is electrically connected to the electric detonator 15. When the operating capacitor 12e is being charged, the initiating capacitor 12f is not charged. When the pre-detonation stage is reached, the initiating capacitor 12f is charged. When the control circuit 12a receives a detonation signal, power is supplied from the initiating capacitor 12f to the electric detonator 15. This causes the electric detonator 15 to ignite and detonate the explosive 2 (see FIG. 2).

[0027] 2, 5, and 6, the antenna 20 also serves as a receiving coil that receives electric energy wirelessly. The antenna 20 transmits and receives wireless signals to and from a relay device 30 (described later) at a frequency that has good penetration into rock, for example, between 1 kHz and 500 kHz, and more preferably between 30 kHz and 300 kHz. The antenna 20 receives electric energy at a frequency of 1 kHz to 500 kHz from a power supply device 4 (described later).

[0028] As shown in FIGS. 3 to 6 , the antenna 20 includes a first coil 21 and a second coil 22. The first coil 21 and the second coil 22 are annularly shaped, with diameters D1 and D2 of 15 mm to 30 mm, respectively. The diameter D1 of the first coil 21 and the diameter D2 of the second coil 22 are substantially the same. The first number of turns of the first coil 21 is, for example, 3 to 15 to suppress impedance. The second number of turns of the second coil 22 is greater than the first number of turns, for example, 30 to 200. The first axis J1 at the center of the first coil 21 and the second axis J2 at the center of the second coil 22 are substantially coaxial, more preferably, aligned coaxially, with the axial direction substantially perpendicular to the face 41. In the present disclosure, substantially coaxial refers to, for example, a relationship in which the first axis J1 or an extension thereof is located within the diameter D2 of the second coil 22, and the second axis J2 or an extension thereof is located within the diameter D1 of the first coil 21.

[0029] As shown in Figures 3 and 4, the first coil 21 and the second coil 22 can be made of, for example, an insulated wire. Insulating coatings such as polyethylene, polyvinyl chloride, and PTFE can prevent short circuits between adjacent wires. This allows the first coil 21 and the second coil 22 to be tightly wound, resulting in an efficient antenna 20. The first coil 21 and the second coil 22 can be made of, for example, an insulated wire coated with an insulating resin such as enamel, polyester, or polyurethane. In this case, the first coil 21 and the second coil 22 can be tightly wound while preventing short circuits between adjacent wires. The first coil 21 and the second coil 22 can be made of, for example, a Litz wire. The Litz wire can reduce loss by suppressing the skin effect and proximity effect.

[0030] As shown in Figures 3, 4, and 6, the antenna 20 has a cylindrical core 24. The core 24 is made of an insulating and lightweight material, such as synthetic resin. The antenna 20 has a magnetic sheet 25 wound around the outer periphery of the core 24. The magnetic sheet 25 is relatively flexible and difficult to break. The first coil 21 and the second coil 22 are wound around the outer periphery of the magnetic sheet 25. This allows the first coil 21 and the second coil 22 to be held coaxially aligned in an annular shape of approximately the same diameter. The magnetic sheet 25 may be a single sheet, or multiple sheets may be wound around the core 24. The magnetic sheet 25 may be wound multiple times around the core 24, for example, two or three times. Note that in Figures 3 and 6, the first coil 21 and the second coil 22 are depicted with different diameters to make them easier to distinguish. In practice, as shown in FIG. 4, the first coil 21 and the second coil 22 are wound around the outer periphery of the magnetic sheet 25 so that the diameter D1 and the diameter D2 are substantially the same.

[0031] As shown in Figures 3, 4, and 6, the magnetic sheet 25 may be a single sheet, or multiple sheets may be arranged and wound around the core material 24 in the axial direction. Using multiple magnetic sheets 25 increases the amount of magnetic material and therefore the inductance. This strengthens the coupling between the magnetic flux of the first coil 21 and the magnetic flux of the second coil 22. Furthermore, using multiple magnetic sheets 25 can average out the performance variations of the individual magnetic sheets 25. This reduces the inductance variations of the antennas 20 of each wireless detonator 10. The magnetic sheet 25 may be wound around the core material 24 multiple times, for example, two or three times. This also increases the amount of magnetic material and therefore the inductance. This strengthens the coupling between the magnetic flux of the first coil 21 and the magnetic flux of the second coil 22.

[0032] 3 and 6, the circuit board 12 is housed in the main body tube 11 alongside the core material 24 in the axial direction of the core material 24. The first coil 21 and the second coil 22 are arranged adjacent to each other in the axial direction of the core material 24. The second coil 22 is arranged at a position farther from the circuit board 12 than the first coil 21 in the axial direction of the core material 24. The second coil 22 generates a stronger electric field than the first coil 21. By separating the second coil 22 from the circuit board 12, the influence of the electric field generated by the second coil 22 on the electronic circuit on the circuit board 12 can be suppressed. The electric detonator 15 is arranged on the opposite side of the antenna 20 with the circuit board 12 in between.

[0033] As shown in FIGS. 3 to 6, the antenna 20 has a resonance capacitor 23. The first coil 21 is electrically connected to the control circuit 12a. The first coil 21 and the second coil 22 are not electrically connected to each other. The resonance capacitor 23 is attached to the circuit board 12 without being electrically connected to the control circuit 12a. The second coil 22 is electrically connected to the resonance capacitor 23. The resonance capacitor 23 includes a fixed capacitor 23a and a variable capacitor 23b, such as a trimmer capacitor. The fixed capacitor 23a allows the inductance of the second coil 22 to be roughly set. The variable capacitor 23b allows the inductance of the second coil 22 to be adjusted. This allows the frequency at which the second coil 22 transmits and receives to be suitably adjusted.

[0034] As shown in FIGS. 1 and 2, the wireless detonation system 1 includes a relay device 30 that relays signals between the blasting device 3 and the wireless detonator 10. The relay device 30 includes a cylindrical main body 31 and an upstream antenna 34 and a downstream antenna 35 that are electrically connected to an electronic circuit 32 within the main body 31. The main body 31 has a diameter smaller than the diameter of an insertion hole 41b formed in the working face 41. The main body 31 is inserted into the insertion hole 41b. The upstream antenna 34 and the downstream antenna 35 are exposed outside the insertion hole 41b. The upstream antenna 34 transmits and receives wireless signals to and from the antenna 3a of the blasting device 3 at a frequency of, for example, 300 MHz to 3 GHz. The downstream antenna 35 transmits and receives wireless signals to and from the antenna 20 of the wireless detonator 10 at a frequency of, for example, 1 kHz to 500 kHz.

[0035] As shown in FIGS. 1 and 2 , the downstream antenna 35 is provided in an annular shape, for example, by winding an electric wire around a ring having a diameter of 300 mm to 1500 mm to form a coil. The downstream antenna 35 is disposed so that its axial direction is approximately perpendicular to the face 41. The axial directions of the first coil 21 and the second coil 22 of the wireless detonator 10 are not parallel to, but at least inclined from, the direction in which the downstream antenna 35 of the relay device 30 and the antenna 20 of each wireless detonator 10 transmit and receive signals. The axial direction of the downstream antenna 35 is also not parallel to, but at least inclined from, the direction in which the downstream antenna 35 and the antenna 20 of each wireless detonator 10 transmit and receive signals. Therefore, the downstream antenna 35 and the antenna 20 of each wireless detonator 10 can efficiently receive changes in the electric field and magnetic field from each other. This allows for efficient transmission and reception of electromagnetic waves between them.

[0036] 2 and 5, the repeater device 30 has an electronic circuit 32 and a power supply 33 housed in a main body 31. The electronic circuit 32 is provided with a CPU that controls the operation of each component of the repeater device 30. The electronic circuit 32 is provided with a receiving circuit and a transmitting circuit corresponding to an upstream antenna 34 and a downstream antenna 35, respectively. The power supply 33 supplies power to each component of the repeater device 30 via the electronic circuit 32.

[0037] As shown in Fig. 6, the wireless detonation system 1 has a power supply device 4 that supplies electric energy to the wireless detonator 10. The power supply device 4 supplies electric power to the operating capacitor 12e of the wireless detonator 10 before it is loaded into the charge hole 41a (see Fig. 2). The power supply device 4 has a cylindrical tube portion 4b that is large enough to cover the outer periphery of the second coil 22. The power supply device 4 has a power supply coil 4a that is wound around the outer periphery of the tube portion 4b. The power supply coil 4a receives electric energy from the second coil 22 of the wireless detonator 10 or transmits and receives wireless signals at a frequency of 1 kHz to 500 kHz.

[0038] As shown in FIG. 6, the power supply device 4 includes a control circuit 4c that controls the operation of each structure of the power supply device 4, and a power supply 4d that supplies power to each structure of the power supply device 4. A power supply circuit 4e is provided on the path between the power supply 4d and the power supply coil 4a. The power supply coil 4a also functions as an antenna that transmits and receives wireless signals to and from the second coil 22. A transmission circuit 4f that modulates the signal and a reception circuit 4g that detects the signal are provided on the path between the control circuit 4c and the power supply coil 4a. The power supply device 4 includes an input unit 4h that can be operated to input information when the power supply coil 4a supplies power or transmits a wireless signal. The power supply device 4 also includes an output unit 4i that can display information received by the power supply coil 4a.

[0039] A series of operations for supplying electrical energy to the wireless detonator 10 will be described with reference to FIGS. 1 to 7. First, the control circuit 4c of the power supply device 4 outputs current from the power source 4d to the power supply coil 4a via the power supply circuit 4e (step 01 in FIG. 7, hereinafter referred to as S01). The power supply coil 4a generates a magnetic field (S02). The second coil 22 of the wireless detonator 10 is inserted inside the power supply coil 4a. A current is generated in the second coil 22 of the wireless detonator 10 by the magnetic field from the power supply coil 4a (S03). The second coil 22 resonates at a predetermined frequency using the resonance capacitor 23. The predetermined frequency is any value in the range of 1 kHz to 500 kHz. The second coil 22 resonates with the magnetic field from the power supply coil 4a, and generates a strong magnetic field in response to a signal of the resonated frequency (S04).

[0040] In the first coil 21, a current is generated as energy due to the magnetic field from the second coil 22 (S05). The changeover switch 12b transmits power to the charging circuit 12c (S06). The charging circuit 12c rectifies the power to DC (S07). The operating capacitor 12e is charged with the electrical energy sent from the charging circuit 12c (S08). When charging of the operating capacitor 12e is completed, the control circuit 12a transmits a charging completion signal to the transmitting circuit 14 (S09). The transmitting circuit 14 modulates the signal and transmits it to the first coil 21 (S10). The first coil 21 generates a magnetic field due to the signal (S11). In the second coil 22, a current is generated due to the magnetic field from the first coil 21 (S12). The second coil 22 resonates at a predetermined frequency in the range of 1 kHz to 500 kHz using the resonant capacitor 23 (S13). The second coil 22 transmits a wireless signal of a resonating frequency to the power feeding coil 4a of the power feeding device 4 (S14).

[0041] The power feeding coil 4a of the power feeding device 4 receives the wireless signal from the second coil 22 (S15). The receiving circuit 4g of the power feeding device 4 detects the signal (S16). The control circuit 4c of the power feeding device 4 receives the detected signal and confirms that charging of one wireless detonator 10 is complete (S17). The output unit 4i of the power feeding device 4 displays that charging is complete (S18).

[0042] 1 to 5 and 8, a series of operations from when the antenna 20 of the wireless detonator 10 receives a wireless signal to when it transmits a reply wireless signal will be described. First, the second coil 22 of the antenna 20 of the wireless detonator 10 receives a wireless signal from the downstream antenna 35 of the relay device 30 (S21). The wireless signal is, for example, a signal that confirms the detonation preparation state of each wireless detonator 10. The second coil 22 resonates at a predetermined frequency using the resonance capacitor 23 to generate a magnetic field (S22). The predetermined frequency is any value in the range of 1 kHz to 500 kHz. In the first coil 21 of the antenna 20 of the wireless detonator 10, a current is generated by the magnetic field from the second coil 22 (S23). The selector switch 12b transmits the signal to the receiving circuit 13 (S24). The receiving circuit 13 detects the signal (S25). The control circuit 12a receives the detected signal (S26).

[0043] The control circuit 12a transmits a reply signal to the transmission circuit 14 (S27). The reply signal is, for example, a signal notifying that each wireless detonator 10 has completed preparation for detonation. The transmission circuit 14 modulates the signal and transmits it to the first coil 21 (S28). The first coil 21 generates a magnetic field in response to the signal (S29). A current flows in the second coil 22 due to the magnetic field from the first coil 21 (S30). The second coil 22 resonates at a predetermined frequency in a preset range of 1 kHz to 500 kHz using the resonance capacitor 23 (S31). The second coil 22 transmits a wireless signal of the resonating frequency to the downstream antenna 35 of the relay device 30 (S32).

[0044] As described above, the wireless detonator 10 has an antenna 20 that transmits and receives wireless signals and receives driving energy wirelessly, as shown in FIGS. 3 to 6. The wireless detonator 10 has an operating capacitor 12e and an initiating capacitor 12f (capacitor) that store the energy received by the antenna 20. The wireless detonator 10 has an electric detonator 15 that detonates with electricity from the initiating capacitor 12f. The antenna 20 has a first coil 21 that is electrically connected to the receiving circuit 13, the transmitting circuit 14, and the operating capacitor 12e and wound with a first number of turns. The antenna 20 has a second coil 22 that is disposed adjacent to the first coil 21 and approximately coaxially with the first coil 21 and wound with a second number of turns that is greater than the first number of turns. The antenna 20 has a resonance capacitor 23 that is electrically connected to the second coil 22.

[0045] Therefore, the second coil 22 electrically connected to the resonance capacitor 23 resonates at a predetermined frequency. As a result, the second coil 22 can efficiently transmit and receive signals of the resonating frequency wirelessly. Furthermore, the impedance can be suppressed by reducing the number of turns of the first coil 21. The second coil 22 can have a large number of turns because its impedance is reduced by resonating with the resonance capacitor 23. When the second coil 22 receives a wireless signal, a current flows in the second coil 22, generating a magnetic field. This causes a current to flow in the first coil 21, transmitting the signal to the first coil 21. When the first coil 21 transmits a signal, a current flows in the first coil 21, generating a magnetic field. This causes a current to flow in the second coil 22, causing the second coil 22 to transmit a wireless signal. Thus, the small antenna 20 of the wireless detonator 10 can increase the efficiency of transmitting and receiving wireless signals.

[0046] As shown in Figure 4, the first coil 21 and the second coil 22 have diameters D1 and D2 that can be inserted into a charge hole 41a (see Figure 2) provided in the working face 41. Therefore, when the wireless detonator 10 is loaded into the charge hole 41a, it is possible to prevent the antenna 20 equipped with the first coil 21 and the second coil 22 from interfering with the inner wall of the charge hole 41a. This allows the wireless detonator 10 to be loaded smoothly into the charge hole 41a.

[0047] As shown in Fig. 2, the antenna 20 transmits and receives wireless signals of 1 kHz to 500 kHz. Therefore, the antenna 20 of the wireless detonator 10 in the charge hole 41a can transmit and receive signals to and from the relay device 30, etc., interposed between the antenna 20 and the blasting device 3 at frequencies that have high rock penetration.

[0048] As shown in FIG. 4, the first coil 21 and the second coil 22 have diameters D1 and D2 of 15 mm to 30 mm. The first number of turns is 3 to 15. The second number of turns is 30 to 200. The ratio of the first number of turns to the second number of turns is preferably 1:5 to 1:50, and more preferably 1:7 to 1:30. Therefore, the antenna 20 of the wireless detonator 10 can be provided with a size that allows efficient transmission and reception and is easy to insert into the charge hole 41a (see FIG. 2). Moreover, the first coil 21 can be provided with a number of turns that can effectively suppress impedance. The second coil 22 can be provided with a number of turns that allows efficient transmission and reception of wireless signals.

[0049] As shown in Figures 3 and 4, the wireless detonator 10 has a core 24 made of an insulating material. The wireless detonator 10 has a magnetic sheet 25 wound around the outer periphery of the core 24. The first coil 21 and the second coil 22 are wound around the outer periphery of the magnetic sheet 25. Therefore, by making the inner periphery of the magnetic sheet 25 the lightweight core 24, the weight of the wireless detonator 10 can be reduced. Furthermore, the highly flexible magnetic sheet 25 is less likely to break. This improves the workability of transporting and loading the wireless detonator 10.

[0050] 3 and 6, the wireless detonator 10 has a circuit board 12 equipped with a receiving circuit 13, a transmitting circuit 14, an operating capacitor 12e, an initiating capacitor 12f, and a resonance capacitor 23. The circuit board 12 is located close to the first coil 21 and far from the second coil 22. Therefore, the second coil 22, which generates a stronger electric field when transmitting and receiving electromagnetic waves, is located farther away from the circuit board 12. This makes it possible to suppress the effect of the electric field on the electronic circuits on the circuit board 12.

[0051] As shown in Figure 5, the resonance capacitor 23 includes a fixed capacitor 23a and a variable capacitor 23b. Therefore, the inductance of the second coil 22 of each wireless detonator 10 varies. The variable capacitor 23b can adjust the variation in inductance of the second coil 22. This allows the second coil 22 to transmit and receive signals at a suitable resonance frequency.

[0052] As shown in Figure 3, the wireless detonator 10 has a main body tube 11. The main body tube 11 houses an antenna 20, an operating capacitor 12e, an initiation capacitor 12f, and an electric detonator 15. This makes the wireless detonator 10 compact and easy to transport. Furthermore, by making the main body tube 11 large enough to be easily loaded into the charge hole 41a (see Figure 2), the workability of loading the wireless detonator 10 can be improved.

[0053] 3 to 6, the wireless detonator antenna 20, which is used in the wireless detonator 10 to transmit and receive wireless signals and to receive driving energy wirelessly, has a first coil 21, a second coil 22, and a resonance capacitor 23. Therefore, by providing the first coil 21 with reduced impedance and the second coil 22 electrically connected to the resonance capacitor 23, it is possible to provide the wireless detonator antenna 20 with high transmission and reception efficiency.

[0054] Although the embodiments of the present invention have been described above, it will be apparent to those skilled in the art that many alternatives, improvements, and modifications can be made without departing from the scope of the present invention. Therefore, the embodiments of the present invention may include all alternatives, improvements, and modifications that do not depart from the spirit and scope of the appended claims. For example, the embodiments of the present invention are not limited to the above structure, and may be modified as follows:

[0055] For example, the wireless detonation system 1 can be used in excavating a tunnel 40 as described above. Alternatively, it may be applied to, for example, breaking up structures such as buildings or excavating the seabed. The loading of the wireless detonator 10 and the installation of the relay device 30 may be performed manually, or may be performed by a loading machine equipped with, for example, a robotic arm. The loading machine may be provided with a power supply device 4 that charges the wireless detonator 10. In the above embodiment, the relay device 30 that transmits and receives signals wirelessly to and from the blasting device 3 is exemplified. Alternatively, the blasting device 3 and the relay device 30 may be configured to transmit and receive signals via a wired connection.

[0056] In the above embodiment, the first coil 21 and the second coil 22 are circular rings of approximately the same diameter and are arranged approximately coaxially. Alternatively, the first coil 21 and the second coil 22 may be arranged in a polygonal ring shape, such as a square, pentagon, hexagon, etc. For example, the first coil 21 may be smaller than the second coil 22 and disposed on the inner periphery of the second coil 22. The second coil 22 may be smaller than the first coil 21 and disposed on the inner periphery of the first coil 21. For example, the first axis J1 of the first coil 21 and the second axis J2 of the second coil 22 may not be coaxial but may be approximately parallel.

[0057] In the above embodiment, the first number of turns of the first coil 21 is 3 to 15. The second number of turns of the second coil 22 is 30 to 200. The first number of turns and the second number of turns may be changed as appropriate as long as the condition that the second number of turns is greater than the first number of turns is satisfied. The winding directions of the first coil 21 and the second coil 22 are not particularly limited and may be any winding direction.

[0058] The resonance capacitor 23 in the above embodiment is attached to the circuit board 12 without being electrically connected to the electronic circuit on the circuit board 12. Alternatively, the resonance capacitor 23 may not be attached to the circuit board 12. The charger in the above embodiment is the operating capacitor 12e and the detonation capacitor 12f provided on the circuit board 12. Alternatively, a small rechargeable battery or the like may be mounted on the wireless detonator 10 as the charger.

[0059] In the above embodiment, the signals transmitted and received by the antenna 20 of the wireless detonator 10 include a signal notifying completion of preparation for detonation and a detonation signal. In addition, the signals may include, for example, a signal for verifying the ID of each wireless detonator 10 loaded in each charging hole 41a, a signal for recording the detonation delay time of each wireless detonator 10, etc. [Explanation of symbols]

[0060] 1. Wireless detonation system 2...Explosive, 2a...Main die, 2b...Additional die 3...blaster, 3a...antenna, 3b...input section, 3c...output section 4... power supply device, 4a... power supply coil, 4b... cylindrical portion, 4c... control circuit, 4d... power supply 4e...power supply circuit, 4f...transmitting circuit, 4g...receiving circuit, 4h...input section, 4i...output section 10...Radio detonator 11...Main body tube, 11a...Bottom, 11b...Cover, 11c...Electric detonator housing 12...circuit board, 12a...control circuit (CPU), 12b...selector switch 12c... charging circuit, 12d... power supply circuit, 12e... operating capacitor (capacitor) 12f...Detonation capacitor (capacitor) 13...Receiver circuit 14...Transmitting circuit 15...Electric detonator 20...Antenna (receiving coil, antenna for wireless detonator) 21...First coil 22...Second coil 23...resonant capacitor, 23a...fixed capacitor, 23b...variable capacitor 24...Core material 25...Magnetic sheet 30...Relay device 31...Main body 32...Electronic circuit 33…Power supply 34...Upstream antenna 35...Downstream antenna 40...Tunnel 41...face, 41a...charge hole, 41b...insertion hole, 41c...sealing member D1, D2…diameter J1…1st axis, J2…2nd axis

Claims

1. A radio detonator, an antenna for transmitting and receiving wireless signals and for receiving driving energy wirelessly; a capacitor that stores the energy received by the antenna; an electric detonator that detonates with electricity from the capacitor; The antenna includes a first coil electrically connected to a receiving circuit, a transmitting circuit, and the capacitor and wound with a first number of turns; a second coil disposed adjacent to the first coil and substantially coaxially therewith, and wound with a second number of turns greater than the first number of turns; A wireless detonator having a resonant capacitor electrically connected to the second coil.

2. The wireless detonator according to claim 1, The first coil and the second coil are wireless detonators having a diameter that can be inserted into a charge hole provided on the face of the firing line.

3. The wireless detonator according to claim 1 or 2, The antenna is a wireless detonator that transmits and receives radio signals in the range of 1 kHz to 500 kHz.

4. The wireless detonator according to claim 1 or 2, The first coil and the second coil have a diameter of 15 mm to 30 mm, the first number of turns is 3 to 15, A wireless detonator in which the second number of turns is 30 to 200.

5. The wireless detonator according to claim 1 or 2, a core material made of an insulating material; A wireless detonator having a magnetic sheet wound around the outer periphery of the core material, and the first coil and the second coil wound around the outer periphery of the magnetic sheet.

6. The wireless detonator according to claim 1 or 2, a circuit board including the receiving circuit, the transmitting circuit, the capacitor, and the resonance capacitor; A wireless detonator in which the circuit board is provided at a position close to the first coil and far from the second coil.

7. The wireless detonator according to claim 1 or 2, The resonant capacitor includes a fixed capacitor and a variable capacitor.

8. The wireless detonator according to claim 1 or 2, It has a main body tube, A wireless detonator in which the antenna, the capacitor, and the electric detonator are housed within the main body tube.

9. 3. An antenna for a wireless detonator, which is used in the wireless detonator according to claim 1 or 2 and transmits and receives a wireless signal and receives driving energy wirelessly, An antenna for a wireless detonator having the first coil, the second coil, and the resonance capacitor.

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