Failure mode detector for rotary machine and method for detecting failure mode

Abstract

To provide a technique by which a user can detect generation of an abnormality or a failure in a rotary machine, by generating unpleasant noises on purpose when a failure mode is generated in the rotary machine.SOLUTION: A failure mode detector 6 has a sound source 7 for generating additional sound which causes unpleasant sounds by interfering with allophones generated when a failure mode is generated in a rotary machine 1. The unpleasant sounds include growling sounds, rough noises, or dissonant sounds.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technology that allows a user to detect that an abnormality or failure has occurred in a rotating machine such as a pump, a blower, a compressor, a turbine, or an electric motor by emitting an unpleasant sound that is unpleasant to humans when a failure mode (e.g., mechanical imbalance, misalignment, or bearing damage) occurs in the rotating machine. [Background technology]

[0002] When an abnormality or failure occurs in a rotating machine such as a pump, a blower, a compressor, a turbine, or an electric motor, the operation of the rotating machine needs to be stopped and the rotating machine needs to be repaired. Since stopping the operation of the rotating machine leads to the stop of the entire system including the rotating machine, it is necessary to detect the abnormality or failure of the rotating machine at an early stage.

[0003] Technologies for diagnosing abnormalities or failures in rotating machinery using sound have already been put to practical use, and for example, narrowband analysis (FFT method) and octave band analysis are used. However, existing technologies diagnose failures using OA (Overall) or POA (Partial Overall), and require sensors to detect sound and processing devices to process the output signals. In addition, the above technologies may not be able to detect failures in cases of relatively high-frequency abnormalities that are not contributing to OA, or abnormalities accompanied by modulated sounds that do not appear in OA or POA. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 040836 [Patent Document 2] Japanese Patent Publication No. 63-281025 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the present invention provides a technique that allows a user to detect that an abnormality or failure has occurred in a rotating machine by intentionally generating an unpleasant sound when a failure mode occurs in the rotating machine. [Means for solving the problem]

[0006] In one aspect, there is provided a failure mode detection device for a rotating machine, the failure mode detection device including a sound source that generates an additional sound that interferes with an abnormal sound generated when a failure mode occurs in the rotating machine, thereby causing an unpleasant sound.

[0007] In one aspect, the sound source is configured to generate the additional sound having a frequency that is a set frequency difference away from a dominant frequency of the abnormal sound, the dominant frequency being predetermined based on the failure mode. In one embodiment, the dominant frequency is a frequency that is N times the rotational frequency of a rotor of the rotating machine (N is a natural number), or a frequency that corresponds to a natural frequency of a component of the rotating machine. In one aspect, the sound source is configured to generate the additional sound such that a composite sound of the abnormal sound and the additional sound becomes an unpleasant sound. In one embodiment, the unpleasant sound is either a rumbling sound, a grating sound, or a discordant sound. In one embodiment, the sound source is an electric sound source that generates the additional sound electrically. In one aspect, the sound source is a mechanical sound source that mechanically generates the additional sound by rotating or vibrating together with a rotor of the rotating machine.

[0008] In one aspect, a failure mode detection method for a rotating machine is provided, the failure mode detection method comprising generating an additional sound from a sound source while a rotor of the rotating machine is rotating, and causing an unpleasant sound to be generated by causing the additional sound to interfere with an abnormal sound generated when a failure mode occurs in the rotating machine.

[0009] In one embodiment, the abnormal noise is a sound having a dominant frequency N times the rotational frequency of the rotor (N is a natural number), and the additional noise is a sound having a frequency that is a set frequency difference away from the dominant frequency. In one aspect, the abnormal noise is a sound having a frequency equal to a natural frequency of a component of the rotating machine, and the additional noise is a sound having a frequency that is separated from the natural frequency by a set frequency difference. In one aspect, the abnormal noise is a sound having a dominant frequency N times the rotational frequency of the rotor (N is a natural number), and the additional noise is a sound in which a combination of the abnormal noise and the additional noise becomes an unpleasant sound. In one aspect, the abnormal noise is a sound having a frequency that is a natural frequency of a component of the rotating machine, and the additional noise is a sound in which a combination of the abnormal noise and the additional noise becomes an unpleasant sound. In one embodiment, the unpleasant sound is either a rumbling sound, a grating sound, or a discordant sound. Effect of the Invention

[0010] When a fault mode occurs in a rotating machine, an abnormal sound with a certain frequency predominates is generated. Additional sounds emitted from the sound source interfere with this abnormal sound and generate unpleasant sounds. Unpleasant sounds are sounds that humans find unpleasant, such as humming, roughness, and discordant sounds. Therefore, when an unpleasant sound is generated from a rotating machine, the user can recognize that some abnormality or failure has occurred in the rotating machine. Unlike conventional techniques for detecting abnormal sounds, this technology does not require sensors to detect sounds or processing devices to process the output signals. In addition, abnormalities accompanied by relatively high frequency sounds that do not contribute to OA (Overall) and abnormalities accompanied by modulated sounds that do not appear in OA (Overall) or POA (Partial Overall) can also be recognized as unpleasant sounds. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram illustrating an embodiment of a mechanical system including a rotating machine and a failure mode detection apparatus. [Diagram 2]FIG. 1 is a schematic diagram illustrating another embodiment of a mechanical system including a rotating machine and a failure mode detection apparatus. [Diagram 3] FIG. 13 is a schematic diagram illustrating yet another embodiment of a mechanical system including a rotating machine and a failure mode detection device. [Figure 4] FIG. 13 is a schematic diagram illustrating yet another embodiment of a mechanical system including a rotating machine and a failure mode detection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a failure mode detection device and a failure mode detection method that generate unpleasant noise when a failure mode occurs in a rotating machine will be described with reference to the drawings. 1 is a schematic diagram showing an embodiment of a mechanical system including a rotating machine and a failure mode detection device. As shown in FIG. 1, the mechanical system includes a rotating machine 1 and a failure mode detection device 6. The failure mode detection device 6 is installed adjacent to the rotating machine 1 or in contact with the rotating machine 1.

[0013] The rotating machine 1 includes a rotor 3 which is a rotating body, a bearing 5 which rotatably supports the rotor 3, and a base 10 on which the bearing 5 is mounted. The base 10 has a bearing holder 12 which holds the bearing 5. The rotor 3 is connected to a drive source such as an electric motor (not shown) and is rotated by the drive source. Examples of the rotating machine 1 include a pump, a blower, a compressor, a turbine, and an electric motor.

[0014] The failure mode detection device 6 includes a sound source 7 configured to generate an additional sound that interferes with the abnormal sound generated when a failure mode occurs in the rotating machine 1. The sound source 7 generates the additional sound during rotation of the rotor 3 of the rotating machine 1. In the embodiment shown in FIG. 1, the sound source 7 is an electric sound source that electrically generates the additional sound. In one embodiment, the sound source 7 includes a sound wave generator 15 that generates a sound signal of a variable frequency, an amplifier 16 that amplifies the sound signal, and a speaker 17 that emits the amplified sound signal as the additional sound. However, as long as the additional sound can be generated electrically, the specific configuration of the sound source 7 is not limited to the embodiment shown in FIG. 1.

[0015] The installation location of the failure mode detection device 6 including the sound source 7 is not limited to the embodiment shown in Fig. 1. The failure mode detection device 6 may be installed at a location away from the rotating machine 1 as long as it can generate an additional sound that interferes with the abnormal sound generated from the rotating machine 1. For example, the failure mode detection device 6 may be installed at a sound receiving point where a user can hear the operating sound of the rotating machine 1. In another example, the failure mode detection device 6 may be a portable device that a user can carry with him / her.

[0016] In another embodiment, the sound source 7 may be a mechanical sound source that mechanically generates the additional sound. For example, as shown in FIG. 2, the sound source 7 may be an impeller 20 directly connected to the rotor 3. The impeller 20 generates the additional sound by rotating together with the rotor 3. When the rotor 3 has a plurality of blades, the impeller 20 can generate the additional sound at a frequency different from the rotation frequency of the rotor 3 by having a number of blades different from the number of blades of the rotor 3. In other words, the frequency of the additional sound can be adjusted by the number of blades of the impeller 20.

[0017] 3, the impeller 20 is connected to the rotor 3 via a plurality of gears 21, 22. In this example, the rotational speed of the impeller 20, i.e., the frequency of the additional sound generated by the impeller 20, can be adjusted by the gear ratio of the plurality of gears 21, 22. The frequency of the additional sound can also be adjusted by the combination of the gear ratio of the gears 21, 22 and the number of blades of the impeller 20.

[0018] In yet another example, as shown in FIG. 4, the sound source 7 may be a mechanical sound source having a cantilever 25 fixed to the base 10. In the example shown in FIG. 4, the end of the cantilever 25 is fixed to the bearing holder 12 of the base 10. As the rotor 3 rotates, the cantilever 25 vibrates and generates an additional sound. The frequency of the additional sound varies depending on the length of the cantilever 25. Therefore, the frequency of the additional sound can be adjusted by the length of the cantilever 25.

[0019] Abnormal noise occurs when a failure mode occurs in the rotating machine 1. Specific examples of failure modes that can occur in the rotating machine 1 include unbalance of the rotor 3, misalignment of the bearings 5, misalignment between the rotor 3 and the driving source (e.g., electric motor), bending of the rotor 3, scratches on the rotor 3, wear of the bearings 5, damage to the bearings 5, etc.

[0020] When these failure modes occur, an abnormal noise with a dominant frequency is generated. The frequency of the abnormal noise, i.e., the dominant frequency, varies depending on the failure mode. For example, when the rotor 3 is unbalanced, an abnormal noise with a dominant frequency that is one time the rotational frequency of the rotor 3 is generated. When there is misalignment between the rotor 3 and the driving source (e.g., an electric motor), when the bearings 5 ​​are worn, or when the rotor 3 is bent, an abnormal noise with a dominant frequency that is one, two, or more times the rotational frequency of the rotor 3 is generated. Therefore, one example of an abnormal noise is a sound with a dominant frequency that is N times the rotational frequency of the rotor 3 (N is a natural number).

[0021] Another example of an abnormal sound is a sound whose frequency is the natural frequency of a component of the rotating machine 1. Specific examples of the component of the rotating machine 1 include the bearing 5 and cooling fins (not shown). For example, when the bearing 5 is worn or damaged, an exciting force is generated that causes the bearing 5 to vibrate. As a result, an abnormal sound is generated whose frequency is predominantly the natural frequency of the bearing 5.

[0022] The sound source 7 generates an additional sound that interferes with the abnormal sound, and generates an unpleasant sound as a result of the interference between the abnormal sound and the additional sound. An unpleasant sound is a sound that a person finds unpleasant. Examples of unpleasant sounds include humming sounds, rough sounds, and discordant sounds.

[0023] Beat sounds are sounds that periodically fluctuate. The strength of the fluctuation of the sound can be expressed by a sound quality index called fluctuation intensity. When the modulation frequency is 4 Hz, humans feel the fluctuation of the sound most strongly. Rough sounds are rough sounds such as buzzing and squeaking. The roughness of sound can be expressed by a sound quality index called roughness. When the modulation frequency is 70Hz, people feel the roughness of sound most strongly. Dissonance is when two or more sounds of different frequencies are not in harmony. The sense of dissonance in a sound can be expressed in terms of the degree of dissonance.

[0024] In one embodiment, the sound source 7 is configured to generate an additional sound having a frequency that is a set frequency difference away from the dominant frequency of the abnormal sound. As described above, the dominant frequency varies depending on the failure mode. Therefore, the dominant frequency used to generate the additional sound is predetermined based on the failure mode. Specifically, the dominant frequency is a frequency that is N times the rotational frequency of the rotor 3 (N is a natural number) or a frequency that corresponds to the natural frequency of a component of the rotating machine 1 (e.g., the bearing 5).

[0025] When the frequency of the abnormal sound (i.e., the dominant frequency) differs from the frequency of the additional sound emitted from the sound source 7, the abnormal sound and the additional sound interfere with each other to generate an unpleasant sound. In one embodiment, the set frequency difference between the abnormal sound and the additional sound is a frequency difference that generates an unpleasant humming sound or roughness sound, and is determined in advance. For example, the set frequency difference is selected from a frequency range of 4 Hz to 70 Hz. The lower limit of this frequency range, 4 Hz, is the frequency at which the sound fluctuation intensity is maximized as described above, and the upper limit of the frequency range, 70 Hz, is the frequency at which the sound roughness is maximized as described above.

[0026] However, even if the sound has a frequency lower than 4 Hz, people can still sense the fluctuation (beat) of the sound. Similarly, even if the sound has a frequency higher than 70 Hz, people can still sense the roughness (coarseness) of the sound. Therefore, in one example, the set frequency difference may be selected from the range of 2 Hz to 100 Hz. In yet another example, the set frequency difference may be selected from the range of 0.25 Hz to 400 Hz, as long as an unpleasant sound is generated.

[0027] In another embodiment, the unpleasant sound is a sound with a high degree of dissonance, that is, a dissonant sound. Like a humming sound or a rough sound, people feel uncomfortable when they hear a dissonant sound. Therefore, the sound source 7 is configured to generate an additional sound that makes the dissonance of a complex sound of the abnormal sound and the additional sound equal to or greater than a predetermined level. The dissonance that represents the sense of dissonance between the abnormal sound and the additional sound depends on the volume and frequency of the abnormal sound and the additional sound. The dissonance that people feel uncomfortable with is determined experimentally or statistically. The above level of dissonance adopted in this embodiment is the level of dissonance that people feel uncomfortable with. Therefore, the sound source 7 generates an additional sound that makes the complex sound of the abnormal sound and the additional sound a dissonant sound.

[0028] When an unpleasant sound is generated from the rotating machine 1, the user can recognize that some kind of abnormality or failure has occurred in the rotating machine 1. Unlike conventional techniques for detecting abnormal sounds, the above-described embodiment does not require a sensor for detecting sound or a processing device for processing the output signal. In addition, an abnormality accompanied by a relatively high frequency sound that does not contribute to the OA (Overall) or an abnormality accompanied by a modulated sound that does not appear in the OA (Overall) or POA (Partial Overall) can also be recognized as an unpleasant sound.

[0029] The above-described embodiments have been described for the purpose of enabling a person having ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope according to the technical idea defined by the claims. [Explanation of symbols]

[0030] 1 Rotating Machinery 3 Rotor 5. Bearings 6. Failure mode detection device 7. Sound Source 10 Foundations 12 Bearing holder 15 Sound Wave Generator 16 Amplifier 17 Speaker 20 Impeller 21,22 Gears 25 Cantilever beam

Claims

1. 1. A failure mode detection apparatus for a rotating machine, comprising: The failure mode detection device includes a sound source that generates an additional sound that interferes with the abnormal sound generated when a failure mode occurs in the rotating machine, thereby causing an unpleasant sound.

2. 2. The failure mode detection device according to claim 1, wherein the sound source is configured to generate the additional sound having a frequency that is a set frequency difference away from a predominant frequency of the abnormal sound, and the predominant frequency is predetermined based on the failure mode.

3. 2. The failure mode detection device according to claim 1, wherein the dominant frequency is a frequency that is N times the rotational frequency of a rotor of the rotating machine (N is a natural number), or a frequency that corresponds to a natural frequency of a component of the rotating machine.

4. The failure mode detection device according to claim 1 , wherein the sound source is configured to generate the additional sound such that a composite sound of the abnormal sound and the additional sound becomes an unpleasant sound.

5. The failure mode detection device according to claim 1 , wherein the unpleasant sound is any one of a humming sound, a rough sound, and a discordant sound.

6. The failure mode detection device according to claim 1 , wherein the sound source is an electric sound source that electrically generates the additional sound.

7. The failure mode detection device according to claim 1 , wherein the sound source is a mechanical sound source that mechanically generates the additional sound by rotating or vibrating together with a rotor of the rotating machine.

8. 1. A method of failure mode detection for a rotating machine, comprising: generating an additional sound from a sound source while the rotor of the rotary machine is rotating; The failure mode detection method includes causing an abnormal noise that occurs when a failure mode occurs in the rotating machine to interfere with the additional sound, thereby generating an unpleasant sound.

9. The abnormal noise has a dominant frequency that is N times the rotational frequency of the rotor (N is a natural number), The failure mode detection method according to claim 8 , wherein the additional sound is a sound having a frequency that is a set frequency difference away from the dominant frequency.

10. The abnormal noise is a sound having a frequency that is a natural frequency of a component of the rotating machine, The failure mode detection method according to claim 8 , wherein the additional sound is a sound having a frequency that is a set frequency difference away from the natural frequency.

11. The abnormal noise has a dominant frequency that is N times the rotational frequency of the rotor (N is a natural number), The failure mode detection method according to claim 8 , wherein the additional sound is a sound in which a composite sound of the abnormal sound and the additional sound becomes an unpleasant sound.

12. The abnormal noise is a sound having a frequency that is a natural frequency of a component of the rotating machine, The failure mode detection method according to claim 8 , wherein the additional sound is a sound in which a composite sound of the abnormal sound and the additional sound becomes an unpleasant sound.

13. The failure mode detection method according to claim 8 , wherein the unpleasant sound is any one of a humming sound, a grating sound, and a discordant sound.

Images