JP2020060460A - Method, device, and program for evaluating noise level of breaker, and breaker - Google Patents

Abstract

To obtain a new index for evaluating a level of noise generated from a breaker.SOLUTION: A device 20 is used to evaluate a level of noise generated from a breaker 10. The device 20 includes a calculator 200. The calculator 200 calculates an attenuation speed of vibration generated from the breaker 10. It was found that a level of noise generated from the breaker 10 becomes smaller for a human auditory sense as the attenuation speed is faster, and a level of noise generated from the breaker 10 becomes larger for a human auditory sensor as the attenuation speed is slower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method, an apparatus and a program for evaluating a noise level of a breaker and a breaker.

  Breakers are sometimes used to crush structures (eg, rock or concrete). The breaker includes a piston, a front head and a chisel. The chisel is attached to the front head. By the impact of the piston, a stress wave propagates from the rear end of the chisel to the tip, and the stress wave propagates from the tip of the chisel toward the structure. This stress wave can fracture the structure.

  Patent Document 1 describes an example of a breaker. This breaker includes a front head, a chisel, and an elastic body (for example, rubber). The outer surface of the chisel includes a small diameter region and a large diameter region protruding outward from the small diameter region. The chisel is attached to the front head such that the large diameter region is located outside the front head. The elastic body is located between the large diameter region of the front head and the chisel. The elastic body contacts both the front head and the large diameter region of the chisel as the chisel returns from the structure towards the front head.

  Non-Patent Document 1 describes evaluation of intermittent noise for human hearing. Specifically, in Non-Patent Document 1, human hearing responds with a delay to the rise of pulse sound waves (intermittent noise) and with a delay to the fall of pulse sound waves (intermittent noise). Is listed. Furthermore, Non-Patent Document 1 describes that if the time of generation of pulse sound waves (intermittent noise) is short, the response level of noise in human hearing may be lowered.

JP, 2008-114297, A

Yoshiyuki Egawa, "Evaluation of loudness of intermittent noise in consideration of hearing characteristics", Research Report of National Institute of Industrial Safety, 1995, p. 27-35

  The inventor has found that the level of noise generated by different breakers may be significantly different for human hearing, although the equivalent noise level of noise generated by different breakers may not be significantly different. Newly found. That is, the present inventor has found that the equivalent noise level may not be a useful index for evaluating the noise level of the breaker in some cases.

  One example of the purpose of the present invention is to obtain a new index for evaluating the level of noise generated from a breaker. Further objects of the invention will be apparent from the following disclosure of embodiments.

According to one aspect of the invention,
A method for evaluating the level of noise generated from a breaker,
A method is provided that includes calculating a damping rate of vibrations generated from the breaker.

According to another aspect of the present invention,
A device for evaluating the level of noise generated from a breaker,
There is provided an apparatus including a calculator for calculating a damping rate of vibration generated from the breaker.

According to still another aspect of the present invention,
A program for causing a computer to function as a device for evaluating the level of noise generated from a breaker,
A program for causing the computer to calculate a damping rate of vibration generated from the breaker is provided.

According to still another aspect of the present invention,
With a piston,
Front head,
A chisel having an outer surface including a first region and a second region protruding outward from the first region, the chisel being attached to the front head such that the second region is located outside the front head. When,
A rigid body located between the front head and the second region of the chisel and having a Young's modulus of 100 GPa or more;
A controller for repeatedly striking the chisel with the piston at a time interval of 100 ms or less;
Including,
A breaker is provided in which the rigid body contacts both the front head and the second region of the chisel during at least a part of the time interval.

  According to the above-mentioned one aspect of the present invention, it is possible to obtain a novel index for evaluating the level of noise generated from the breaker.

It is a figure for explaining the breaker concerning Embodiment 1, and the device concerning Embodiment 1. It is a figure for explaining the breaker concerning Embodiment 1, and the device concerning Embodiment 1. FIG. 3 is a diagram showing a sound waveform of the breaker according to the first embodiment. It is a figure which shows the waveform of the sound of the breaker which concerns on a comparative example. FIG. 4 is a diagram for explaining an example of a method of calculating a sound attenuation speed in FIG. 3. 5 is a diagram for explaining an example of a method of calculating a sound attenuation speed in FIG. 4. FIG. FIG. 7 is a diagram for explaining the device according to the second embodiment. It is a figure for explaining an example of reference data memorized by memory. It is a figure which shows an example of the hardware constitutions of an apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same constituents will be referred to with the same numerals, and the description thereof will not be repeated.

  In the following description, the calculator 200, the determiner 210, and the storage device 220 of the device 20 are not hardware-based configurations, but functional-based blocks. The calculator 200, the determiner 210, and the storage device 220 of the device 20 are a CPU of any computer, a memory, a program loaded into the memory, which realizes the constituent elements of this figure, a storage medium such as a hard disk for storing the program, It is realized by an arbitrary combination of hardware and software centered on a network connection interface. Then, there are various modified examples of the realization method and the device.

(Embodiment 1)
1 and 2 are diagrams for explaining a breaker 10 according to the first embodiment and a device 20 according to the first embodiment.

  The outline of the device 20 will be described with reference to FIG. The device 20 is for evaluating the level of noise generated from the breaker 10. The device 20 includes a calculator 200. The calculator 200 is for calculating the damping speed of the vibration generated from the breaker 10.

  According to the configuration described above, a new index for evaluating the level of noise generated from the breaker 10 can be obtained. Specifically, in the above-described configuration, the damping rate of the vibration generated from the breaker 10 can be calculated by the calculator 200. This damping speed can be a new index for evaluating the level of noise generated from the breaker 10.

  Specifically, the inventor has found that the higher the damping speed described above, the lower the level of noise generated by the breaker 10 for human hearing, and the lower the damping speed described above, the lower the level of noise generated by the breaker 10. It was found to be great for the hearing of. Therefore, the level of noise generated from the breaker 10 can be determined based on the above-described damping speed.

  Furthermore, the present inventor has found that even when there is no significant difference in the equivalent noise level of the noise generated from the breaker 10, the above-mentioned damping speed can have a significant difference. Therefore, the level of noise that cannot be determined by the equivalent noise level can be determined based on the above-described attenuation speed.

  As is apparent from the above description, the device 20 is also able to evaluate the level of noise generated by a breaker different from the breaker 10 shown in FIGS.

  The outline of the breaker 10 will be described with reference to FIG. The breaker 10 includes a piston 110, a front head 120, a chisel 130, a rigid body 140, and a controller 150. The chisel 130 has an outer surface 132. The outer side surface 132 includes a first region 132a and a second region 132b. The second area 132b projects outward from the first area 132a. The outer side surface 132 is attached to the front head 120 so that the second region 132b is located outside the front head 120. The rigid body 140 is located between the front head 120 and the second region 132b of the chisel 130. The rigid body 140 has a Young's modulus of 100 GPa or more. The controller 150 is for repeatedly striking the piston 110 with the chisel 130 at a time interval of 100 ms or less. The rigid body 140 contacts both the front head 120 and the second region 132b of the chisel 130 during at least a part of the time interval.

  According to the configuration described above, the level of noise generated from the breaker 10 can be reduced for human hearing. Specifically, in the configuration described above, the damping speed of the vibration generated from the breaker 10 can be increased by the rigid body 140. As described above, the higher the damping speed, the lower the level of noise generated by the breaker 10 may be for human hearing. Furthermore, in the above-described configuration, the piston 110 repeatedly strikes the chisel 130 at a time interval of 100 ms or less, and the generation time of the sound wave in each striking by the piston 110 (excluding the time when the sound wave decays). It can be suppressed to less than 100 ms. As described in Non-Patent Document 1, if the sound wave generation time is short, the response level of noise in human hearing may decrease. In this way, the level of noise generated from the breaker 10 can be reduced for human hearing.

  Details of the breaker 10 will be described with reference to FIGS. 1 and 2. FIG. 1 shows the breaker 10 at the timing when the piston 110 hits the chisel 130. FIG. 2 shows the breaker 10 at a timing after the breaker 10 hits the chisel 130.

  The piston 110 can reciprocate by pressure (for example, hydraulic pressure).

  The outer surface 132 of the chisel 130 includes a first area 132a, a second area 132b, and a third area 132c. The first region 132a, the second region 132b, and the third region 132c are arranged in order from the front end to the rear end of the chisel 130. The second region 132b projects outward from both the first region 132a and the third region 132c.

  The chisel 130 is reciprocally attached to the front head 120. The chisel 130 is attached to the front head 120 so that the third region 132c of the chisel 130 is inserted into the front head 120.

  The rigid body 140 is attached to the third region 132c of the chisel 130. In one example, the rigid body 140 may have a shape (for example, a circular shape) that surrounds the third region 132c of the chisel 130.

  The rigid body 140 has a high Young's modulus. Therefore, the rigid body 140 does not substantially deform even when an external force is applied to the rigid body 140. In one example, the rigid body 140 can be steel.

  The controller 150 is for repeatedly striking the piston 110 against the chisel 130. The controller 150 may cause the piston 110 to strike the chisel 130 periodically, or may cause the piston 110 to strike the chisel 130 aperiodically. The controller 150 may control the time interval described above by controlling the movement of the piston 110.

  The controller 150 may be housed in the body of the breaker 10 (the front head 120 is a part of the body of the breaker 10 in FIGS. 1 and 2), or the body of the breaker 10. It may be arranged outside.

  The operation of the breaker 10 will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the tip of the chisel 130 is pressed against the structure O (for example, rock or concrete). In this way, the chisel 130 can be moved toward the front head 120, and the rigid body 140 contacts both the front head 120 and the second region 132b of the chisel 130.

  Next, as shown in FIG. 2, the rear end of the chisel 130 is struck by the piston 110. By the impact of the piston 110, a stress wave propagates from the rear end of the chisel 130 toward the tip, and the stress wave propagates from the tip of the chisel 130 toward the structure O. The structure O can be crushed by this stress wave.

  Next, the piston 110 moves in a direction away from the chisel 130. Then, the operation shown in FIGS. 1 and 2 is repeated.

  In the present embodiment, the damping speed of the vibration of the chisel 130 can be increased by the rigid body 140. Specifically, with the front head 120 pressing the tip of the chisel 130 against the structure O, the piston 110 strikes the chisel 130. Particularly, at the timing when the chisel 130 is hit by the piston 110, the length of the chisel 130 contracts due to elastic deformation of the chisel 130. Therefore, the contact pressure that the rigid body 140 receives from the front head 120 and the second region 132b of the chisel 130 temporarily decreases. However, after that, the stress wave that is a reflected wave from the tip of the chisel 130 returns the deformation of the chisel 130. When the deformation of the chisel 130 returns, the rigid body 140 comes into contact with both the front head 120 and the second region 132b of the chisel 130. Thereafter, the vibration of the chisel 130 can be amplified (resonated) by superposition of the stress wave propagating from the rear end of the chisel 130 toward the tip and the reflected stress wave from the tip of the chisel 130. However, before the vibration of the chisel 130 is amplified, the rigid body 140 is pressed against both the front head 120 and the second region 132b of the chisel 130, and the rigid body 140 is not substantially deformed. Vibration is suppressed, and the damping rate of vibration can be increased.

  Most of the noise generated from the breaker 10 is due to the vibration generated from the chisel 130 due to the impact of the piston 110. In the present embodiment, the chisel 130 can be pressed by the rigid body 140 and the structure O at the timing of hitting the piston 110. Therefore, the damping speed of the vibration of the chisel 130 can be increased by the rigid body 140.

  Particularly in this embodiment, the damping speed of the vibration of the chisel 130 can be increased by the high rigidity of the rigid body 140. Due to the high rigidity of the rigid body 140, the deformation (that is, vibration) of the rigid body 140 due to the vibration of the chisel 130 can be suppressed. Therefore, the vibration damping rate of the chisel 130 is suppressed by the high-rigidity member (that is, the rigid body 140) as compared with the case where the chisel 130 is pressed by the low-rigidity member (for example, the elastic body). Can be high.

  FIG. 3 is a diagram showing a sound waveform of the breaker 10 according to the first embodiment. The lower part of FIG. 3 is an enlarged view of the broken line part of the upper part of FIG. FIG. 4 is a diagram showing a sound waveform of the breaker 10 according to the comparative example. The lower part of FIG. 4 is an enlarged view of the broken line part of the upper part of FIG.

  The breaker 10 according to the comparative example is the same as the breaker 10 according to the first embodiment except that the rigid body 140 is not provided.

  The waveform of FIG. 3 shows a sound wave at a position 1 m away from the chisel 130. In FIG. 3, the piston 110 repeatedly strikes the chisel 130 at a cycle of about 50 ms.

  The waveform of FIG. 4 shows a sound wave at a position 1 m away from the chisel 130. In FIG. 4, the piston 110 repeatedly strikes the chisel 130 at a cycle of about 50 ms.

  The equivalent noise level in FIG. 3 was 108.5 dB (A), and the equivalent noise level in FIG. 4 was 110 dB (A). Although the equivalent noise level in Embodiment 1 (FIG. 3) is lower than the equivalent noise level in Comparative Example (FIG. 4), the equivalent noise level in Embodiment 1 (FIG. 3) and the equivalent noise level in Comparative Example (FIG. 4) are The difference is not significant (generally, a significant difference to human hearing in terms of equivalent noise level is about 3 dB or more). However, for human hearing, the noise level of the first embodiment (FIG. 3) was lower than that of the comparative example (FIG. 4).

  As a result of examination by the present inventor, as will be described later, it has become clear that the vibration damping rate in the first embodiment (FIG. 3) is higher than the vibration damping rate in the comparative example (FIG. 4). That is, even if the noise level of the breaker 10 cannot be determined based on the equivalent noise level, the noise level of the breaker 10 can be determined based on the damping speed of the vibration generated from the breaker 10.

  FIG. 5 is a diagram for explaining an example of a method for calculating the vibration damping rate in FIG. FIG. 6 is a diagram for explaining an example of a method for calculating the vibration damping rate in FIG. 4.

  In the example shown in FIGS. 5 and 6, the calculator 200 shown in FIGS. 1 and 2 calculates the vibration damping speed of the breaker 10 (that is, the vibration damping speed of the chisel 130) as follows. can do.

In the example shown in FIG. 5, the calculator 200 calculates the falling time constant τ of the absolute value plot of each plot of the waveform shown in the lower part of FIG. More specifically, the calculator 200 calculates the absolute value of each plot of the waveform shown in the lower part of FIG. 3, and plots the ratio of each absolute value to the maximum absolute value in the lower part of FIG. In FIG. 5, this ratio is plotted. The calculator 200 approximates the function f (t) = e ^{−t / τ} to the plot shown in FIG. 5 to calculate the time constant τ.

  The time constant τ in the first embodiment (FIG. 5) was 1.89 ms.

  Also in the example shown in FIG. 6, the calculator 200 calculates the time constant τ in the same manner as the method described with reference to FIG.

  The time constant τ in the comparative example (FIG. 6) was 2.53 ms.

  The damping rate of vibration can be evaluated based on the time constant τ. Specifically, it can be said that the smaller the time constant τ, the larger the vibration damping rate, and the larger the time constant τ, the smaller the vibration damping rate.

  The time constant τ in the first embodiment (FIG. 5) is smaller than the time constant τ in the comparative example (FIG. 6). Therefore, it can be said that the vibration damping rate in the first embodiment (FIG. 5) is higher than the vibration damping rate in the comparative example (FIG. 6).

  The method of calculating the vibration damping speed of the breaker 10 is not limited to the examples shown in FIGS. In another example, the calculator 200 may calculate the damping rate of the vibration of the breaker 10 from the envelope of the waveform (for example, the waveform shown in the lower part of FIG. 3 or the waveform shown in the lower part of FIG. 4). .

  The damping rate calculated by the calculator 200 may be the damping rate of the vibration (eg, sound wave or stress wave) generated from the chisel 130, or the vibration (eg, sound wave or stress wave) generated from the front head 120. ) May be sufficient. Due to the propagation of the vibration generated from the chisel 130, the front head 120 may also generate vibration.

(Embodiment 2)
FIG. 7 is a diagram for explaining the device 20 according to the second embodiment. The device 20 according to the second embodiment is the same as the device 20 according to the first embodiment except for the following points. The breaker 10 according to the second embodiment is the same as the breaker 10 according to the first embodiment.

  The device 20 includes a determiner 210 and a memory 220. The determiner 210 is for determining the noise level of the breaker 10 based on the damping speed calculated by the calculator 200. The determiner 210 may compare the data indicating the damping rate calculated by the calculator 200 with the reference data stored in the memory 220, and determine the noise level of the breaker 10 based on this comparison. May be.

  FIG. 8 is a diagram for explaining an example of reference data stored in the storage device 220.

  The reference data are attenuation speeds (v1, v2, v3, ..., Left column of FIG. 8) associated with the levels of noise generated from the breaker 10 (L1, L2, L3, ..., Right column of FIG. 8).・ ・) Is shown. The reference data can be generated by measuring the relationship between the damping speed and the noise level in advance.

  FIG. 9 is a diagram illustrating an example of the hardware configuration of the device 20.

  The device 20 includes a bus 21, a processor 22, a memory 23, a storage device 24, and an input / output interface (I / F) 25.

  The bus 21 is a data transmission path for the processor 22, the memory 23, the storage device 24, and the input / output I / F 25 to mutually transmit and receive data. However, the method of connecting the processor 22, the memory 23, the storage device 24, and the input / output I / F 25 to each other is not limited to bus connection.

  The processor 22 is a computing device (for example, a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit)).

  The memory 23 is a main storage device (for example, a RAM (Random Access Memory) or a ROM (Read Only Memory)).

  The storage device 24 is an auxiliary storage device (for example, HDD (Hard Disk Drive), SSD (Solid State Drive), or memory card).

  The storage device 24 stores a program module that implements each functional component of the apparatus 20 (for example, the calculator 200 or the determiner 210). The processor 22 realizes the function corresponding to each program module by reading each program module into the memory 23 and executing it.

  The input / output I / F 25 includes an interface (for example, a sound wave detector (for example, microphone)) for acquiring the vibration generated from the breaker 10.

  Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than the above may be adopted.

10 breaker 20 device 21 bus 22 processor 23 memory 24 storage device 25 input / output I / F
110 piston 120 front head 130 chisel 132 outer side surface 132a first region 132b second region 132c third region 140 rigid body 150 controller 200 calculator 210 determiner 220 storage device

Claims (6)

A method for evaluating the level of noise generated from a breaker,
Calculating a damping rate of vibrations generated from the breaker. The method of claim 1, wherein
The method of calculating the damping rate of the vibration generated from the breaker comprises calculating a damping rate of vibration generated from the breaker's chisel. The method according to claim 1 or 2,
The method further comprising comparing the data indicative of the decay rate with reference data indicative of the decay rate associated with the level of noise generated by the breaker. A device for evaluating the level of noise generated from a breaker,
An apparatus including a calculator for calculating a damping rate of vibration generated from the breaker. A program for causing a computer to function as a device for evaluating the level of noise generated from a breaker,
A program for causing the computer to calculate a damping rate of vibration generated from the breaker. With a piston,
Front head,
A chisel having an outer surface including a first region and a second region protruding outward from the first region, the chisel being attached to the front head such that the second region is located outside the front head. When,
A rigid body located between the front head and the second region of the chisel and having a Young's modulus of 100 GPa or more;
A controller for repeatedly striking the chisel with the piston at a time interval of 100 ms or less;
Including,
The breaker, wherein the rigid body is in contact with both the front head and the second region of the chisel during at least a part of the time interval.

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