JP2010150933A - Resonator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resonator having a noise reducing characteristic in a wide frequency range and easily changing the noise reducing characteristic. <P>SOLUTION: This resonator 20 includes a first resonant chamber 21a, a second resonant chamber 21b and a third resonant chamber 21c which are partitioned inside of a body case 21 by partitioning plates 23 formed with communication holes 23a. The resonant chambers 21a, 21b, 21c are connected to an air intake duct 11 through communication pipes 22. The resonant frequencies of the resonant chambers 21a, 21b, 21c are set to have a frequency interval of 50-200 Hz by changing at least one of the length and inner diameters of the communication pipes 22 and the inner volumes of the resonant chambers 21a, 21b, 21c. Thereby, it is possible to reduce noise propagating through the duct 11 over the wide frequency range and to easily change the noise reducing characteristic reducing noise. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resonator that reduces the propagation sound that propagates through a tubular body, and more particularly to a resonator that reduces the noise that propagates through a duct mounted on a vehicle.

  In general, in a pipe (duct) connected to a device that emits sound when activated, it is well known that sound generated from the device propagates through the intake passage and radiates from the open end. It has been. Such pipes (ducts) are widely used in various fields. In particular, in a vehicle, a pipe (air intake duct) for introducing air into an engine and a pipe for air conditioning a vehicle interior. (Air conditioning duct) etc. are provided. And in a vehicle, since these pipe bodies (ducts) are provided at a position close to the occupant, it is easy for the occupant to perceive a propagation sound emitted from these pipe bodies (ducts) as noise. For this reason, in order to reduce the propagation sound (noise) which propagates to a pipe body (duct), providing a resonator is implemented widely.

With respect to this resonator, conventionally, for example, as shown in Patent Document 1 below, a partition member that divides the inside of the main body case into a plurality of resonance chambers has been provided, and a communication that communicates the plurality of resonance chambers with the partition member. Resonators with holes are known. This conventional resonator is a Helmholtz type resonator and silences (reduces) noise having a frequency corresponding to each resonance chamber formed in the main body case. Further, by providing communication holes in the partition member that divides the resonance chambers, the respective resonance chambers can be communicated with each other so that one large resonance chamber can be formed. Thereby, according to this conventional resonator, in addition to being able to reduce noise by each resonance chamber, noise can also be reduced by one large resonance chamber, so noise in a wider frequency range can be reduced. Can be reduced.
Japanese Patent Laid-Open No. 2005-155502

  The conventional resonator has an excellent noise reduction characteristic that noise in a wide frequency range can be reduced by one resonator. However, when actually reducing the noise propagating through a pipe using such a resonator, the noise reduction characteristic is maintained in accordance with the required noise reduction level while maintaining this excellent noise reduction characteristic. It is desirable that it can be changed. It is desirable that the noise reduction characteristic can be easily changed under a limited installation environment of the resonator.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a resonator having noise reduction characteristics in a wide frequency range and capable of easily changing the noise reduction characteristics. It is in.

  A feature of the present invention is that a main body case that is disposed outside a tubular body through which gas can pass and divides a predetermined internal volume, a communication pipe that connects the tubular body and the main body case in a communicating state, and the main body A resonator having a partition member disposed in a case and partitioning the inside of the main body case into a plurality of resonance chambers and having a communication hole that communicates the plurality of resonance chambers with each other, and corresponds to the plurality of resonance chambers This is because each resonance frequency is set to have a predetermined frequency interval.

  In this case, the predetermined frequency interval may be a frequency interval larger than 50 Hz and smaller than 200 Hz, for example.

  Further, each resonance frequency corresponding to the plurality of resonance chambers can be obtained, for example, by changing at least one of the length of the communication tube, the inner diameter of the communication tube, and the internal volumes of the plurality of resonance chambers. The predetermined frequency interval may be set.

  According to these, since the plurality of resonance chambers are formed in the main body case by the partition member, noise having a frequency that matches the resonance frequency corresponding to each resonance chamber can be reduced satisfactorily. Further, since the formed resonance chambers can communicate with each other, one large resonance chamber can be formed in the main body case, and noise having a frequency that matches the resonance frequency corresponding to the large resonance chamber can be generated. It can be reduced satisfactorily. Thereby, the noise reduction characteristic which reduces the noise of a wide frequency range favorably can be exhibited.

  And in setting the resonance frequency in each resonance chamber formed by the partition member, the noise reduction characteristic can be appropriately changed by setting the frequency interval of these resonance frequencies in the range of 50 Hz to 200 Hz. Specifically, as the frequency interval of the resonance frequency is set to be small, noise that effectively reduces noise in a low frequency range while exhibiting noise reduction characteristics that favorably reduce noise in a wide frequency range. The reduction characteristic can be changed. On the other hand, as the frequency interval of the resonance frequency is set larger, the noise reduction characteristic that effectively reduces the noise in the high frequency range while mainly exhibiting the noise reduction characteristic that reduces the noise in a wide frequency range well. Can be changed. Therefore, for example, it is possible to appropriately change the noise reduction characteristics in accordance with the required noise reduction level that varies depending on the usage environment of the resonator.

  Further, the resonance frequency of each resonance chamber formed by the partition member is set by changing at least one of the length of the communication tube, the inner diameter of the communication tube, and the internal volumes of the plurality of resonance chambers. Thus, the noise reduction characteristic can be changed as described above. Thereby, for example, even when the shape of the resonator is limited due to mounting requirements on the vehicle, the resonance frequency can be easily changed and set. Therefore, it is possible to appropriately change the noise reduction characteristic in accordance with the required noise reduction level.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows a state in which a resonator 20 according to an embodiment of the present invention is assembled to an intake system K of a vehicle. The intake system K includes an intake duct 11, an air cleaner 12, and an air cleaner hose 13.

  The intake duct 11 conducts outside air (air) sucked by the engine 14, has an inlet 11 a that opens to the front of the vehicle on one end side, and is connected to the air cleaner 12 on the other end side. A resonator 20 is connected to the intake duct 11. The air cleaner 12 includes an air cleaner element 12a inside and filters the air introduced by the intake duct 11. The air cleaner hose 13 is provided between the air cleaner 12 and the engine 14. The air cleaner hose 13 supplies the air filtered by the air cleaner element 12 a of the air cleaner 12 to the engine 14 via the throttle body 15.

  The resonator 20 is a Helmholtz type resonator, and reduces noise generated when the engine 14 sucks outside air (air) through the intake duct 11 and propagates through the duct 11 by resonance. For this reason, the resonator 20 includes a hollow main body case 21, a communication pipe 22 that connects the intake duct 11 and the main body case 21 in communication, and a partition plate 23 that divides the main body case 21 into a plurality of resonance chambers. It has.

  The main body case 21 is formed in a hollow box shape, and is shaped so that its internal space has a predetermined internal volume. As will be described later, the communication pipe 22 communicates with each of the plurality of resonance chambers (three in the present embodiment) formed in the main body case 21 by being partitioned by the partition plate 23 and the intake duct 11. It connects with. The partition plate 23 is formed in a thin plate shape, and forms a first resonance chamber 21 a, a second resonance chamber 21 b, and a third resonance chamber 21 c in the main body case 21. In addition, the partition plate 23 is arrange | positioned in the main body case 21 so that the internal volume of the 1st resonance chamber 21a, the 2nd resonance chamber 21b, and the 3rd resonance chamber 21c may mutually differ. The partition plate 23 is formed with a communication port 23a that allows communication between the formed first resonance chamber 21a, second resonance chamber 21b, and third resonance chamber 21c. The communication port 23a only needs to be opened to such an extent that air existing in the main body case 21 can be conducted between the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c.

  Here, in general, in a Helmholtz resonator, a predetermined frequency component of a propagation sound (noise) propagating in a pipe body (intake duct), that is, a sound of a propagation sound (noise) resonating with a resonance frequency in a resonance chamber. Reduce pressure level. For this reason, in the resonator 20, the partition plate 23 divides the inside of the main body case 21 to form the three resonance chambers 21a, 21b, and 21c, whereby the resonance corresponding to each of the three resonance chambers 21a, 21b, and 21c. Demonstrates noise reduction characteristics to reduce frequency noise. In the resonator 20, the communication port 23 a is formed in the partition plate 23, so that the three resonance chambers 21 a, 21 b, and 21 c communicate with each other and function as one large resonance chamber. It exhibits noise reduction characteristics that reduce the noise at the corresponding resonance frequency.

ただし、前記式１，２中のCは音速を表し、前記式１，３中のSは連通管２２の断面積を表し、前記式１中のVは共鳴室としての本体ケース２１の内容積を表し、前記式２中のtは温度を表し、前記式３，４中のDは連通管２２の内径を表し、前記式４中のLpは開口端補正した連通管２２の長さを表し、前記式４中のL1は開口端補正前の連通管２２の長さを表す。 In such a Helmholtz type resonator 20, the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c communicate with each other so that the entire internal space of the main body case 21 serves as a resonance chamber. f0 can be calculated | required by following formula 1-4.

However, C in the formulas 1 and 2 represents the speed of sound, S in the formulas 1 and 3 represents a cross-sectional area of the communication pipe 22, and V in the formula 1 represents the internal volume of the main body case 21 as a resonance chamber. T in the formula 2 represents the temperature, D in the formulas 3 and 4 represents the inner diameter of the communication pipe 22, and Lp in the formula 4 represents the length of the communication pipe 22 corrected for the opening end. , L1 in the equation 4 represents the length of the communication pipe 22 before opening end correction.

  On the other hand, in the case of the resonator 20 in which the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c are formed by the partition plate 23, the resonance chambers 21a, 21b, and 21c communicate with the intake duct 11. The length L1 and the inner diameter D of the communication tube 22 and the internal volumes V of the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c (hereinafter, these values are also referred to as parameters) are varied. Can be set. Therefore, based on the relations of the equations 1 to 4, the resonance chambers 21a, 21b, and 21c can have different resonance frequencies f1 to f3 by appropriately setting parameters.

  Therefore, according to the resonator 20, the resonance frequency f0 when the entire internal space of the main body case 21 is used as the resonance chamber and the resonance frequencies f1 to f3 that are different for the resonance chambers 21a, 21b, and 21c are appropriately set. Thus, it is possible to suitably reduce noise in a desired frequency range (for example, near 100 Hz to 400 Hz) among the noise propagating in the intake duct 11. Since the resonance frequency f0 may not be changed depending on the requirements for mounting on the vehicle, in practice, the resonance frequencies f1 to f3 need to be set appropriately.

  By the way, when the resonance frequencies f1 to f3 are set to reduce noise in a desired frequency range, noise having a frequency matching the resonance frequencies f1 to f3 is greatly reduced by resonance, but the resonance frequencies f1 to f3 are reduced. Noise with frequencies other than f3 is difficult to reduce. That is, at the frequency of the noise that matches the resonance frequency f1 to f3, since the noise reduction effect by resonance is large, a “valley” is formed in the frequency axis direction of the noise, and the other portions are formed as “valleys”. In response to the tilt, the so-called anti-resonance is generated, so that the noise reduction effect is deteriorated, and a “mountain” is formed in the frequency axis direction of the noise. Therefore, anti-resonance may occur, and noise may not be appropriately reduced over the entire desired frequency range.

  Here, the occurrence of anti-resonance becomes significant when a plurality of resonance chambers 21a, 21b, and 21c are formed in the main body case 21 by the partition plate 23 in which the communication port 23a is not formed, as will be described later. By forming the communication port 23a in the plate 23 and connecting the resonance chambers 21a, 21b, 21c to each other, the occurrence of anti-resonance can be suppressed. And by suppressing generation | occurrence | production of antiresonance, the noise reduction characteristic which reduces a noise favorably in a desired frequency range can be acquired. However, by simply forming the communication port 23a and allowing the resonance chambers 21a, 21b, and 21c to communicate with each other as described above, the occurrence of anti-resonance can be suppressed, but the noise reduction characteristic corresponds to the required level. Cannot be changed as appropriate.

  In this regard, the inventor of the present application has repeatedly performed various experiments, and as a result, the resonator 20 that allows the resonance chambers 21a, 21b, and 21c to communicate with each other depends on the frequency intervals of the resonance frequencies f1, f2, and f3. As a result, it was found that the noise reduction characteristic in the desired frequency range can be appropriately changed according to the required level by appropriately setting the frequency interval. That is, the inventor of the present application, among the above parameters, the length L1 of the communication tube 22, the inner diameter D of the communication tube, and the internal volumes of the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c. It was found that by changing the frequency interval between the resonance frequencies f1, f2, and f3 by changing at least one of V, the noise reduction characteristics in the frequency range where noise should be reduced can be changed and set. . Hereinafter, the change in noise reduction characteristics accompanying the change in the frequency interval setting will be described in detail.

  In order to appropriately set the frequency interval between the resonance frequencies f1, f2, and f3, the inventor of the present application manufactured and manufactured a resonator 20S for evaluation having frequency intervals of 50 Hz, 100 Hz, 150 Hz, 200 Hz, and 250 Hz. An evaluation product in which the resonator 20S was assembled to the intake duct 11 was produced. Then, the settable range of the frequency interval between the resonance frequencies f1, f2, and f3 was determined by evaluating the noise reduction characteristics of the evaluated product. Hereinafter, the noise reduction characteristics of the evaluation product assembled with the resonator 20S having a frequency interval of 100 Hz will be described first.

  The noise reduction characteristics were evaluated using a measuring apparatus schematically shown in FIG. More specifically, with respect to the intake duct 11 constituting the evaluation product, a sound collection microphone for collecting radiated sound emitted after passing through the resonator 20S is arranged on the suction port 11a side which is the front end side. A speaker that generates a reference sound (white noise) by continuously changing the frequency is disposed on the proximal end side of the intake duct 11. Then, a reference sound whose frequency is continuously changed is generated from the speaker, and radiated sound radiated from the suction port 11a of the intake duct 11 through the resonator 20S is collected by the sound collecting microphone, and the sound pressure level of the reference sound is collected. The ratio P2 / P1 of the sound pressure level P2 of the collected sound with respect to P1 (hereinafter, this ratio P2 / P1 is referred to as acoustic transfer characteristic P2 / P1) was measured. The sound transfer characteristic P2 / P1 is assumed to be a noise reduction characteristic. The smaller the value of the sound transfer characteristic P2 / P1, the greater the noise reduction effect, and the larger the value of the sound transfer characteristic P2 / P1, the noise. It was judged that the reduction effect was small.

このようにパラメータを設定したレゾネータ２０Ｓにおいては、前記式１〜４を用いた計算により、第２共鳴室２１ｂの共鳴周波数f2は第１共鳴室２１ａの共鳴周波数f1に対してほぼ１００Ｈｚ大きな周波数となり、第３共鳴室２１ｃの共鳴周波数f3は第２共鳴室２１ｂの共鳴周波数f2に対してほぼ１００Ｈｚ大きな周波数となることを確認した。 a. When the frequency interval is 100 Hz: The resonator 20S was manufactured with the parameters set as shown in Table 1 below so that the frequency interval between the resonance frequencies f1, f2, and f3 was approximately 100 Hz.

In the resonator 20S in which the parameters are set as described above, the resonance frequency f2 of the second resonance chamber 21b is approximately 100 Hz larger than the resonance frequency f1 of the first resonance chamber 21a by the calculation using the equations 1 to 4. It was confirmed that the resonance frequency f3 of the third resonance chamber 21c was approximately 100 Hz larger than the resonance frequency f2 of the second resonance chamber 21b.

  2 was used to measure the acoustic transfer characteristic P2 / P1 (that is, noise reduction characteristic) of an evaluation product in which the resonator 20S was assembled to the intake duct 11. In addition, in order to evaluate the acoustic transmission characteristic P2 / P1 of the evaluation product, for reference, the acoustic transmission characteristic P2 / P1 of the intake duct 11 only (hereinafter referred to as the acoustic transmission characteristic P2 / P1 of the intake duct) and the communication port 23a A comparative product acoustic transmission characteristic P2 / P1 (hereinafter referred to as a comparative product acoustic transmission characteristic P2 / P1) in which the resonator 20B in which the main body case 21 is partitioned by the partition plate 23 not formed with the suction duct 11 is also assembled. It was measured. The measurement results are shown in FIG.

  As apparent from FIG. 3, the acoustic transfer characteristic P2 / P1 of the intake duct indicated by the broken line has a peak when the frequency is approximately 320 Hz. In addition, the acoustic transfer characteristic P2 / P1 of the comparative product indicated by the alternate long and short dash line is substantially smaller than the acoustic transfer characteristic P2 / P1 of the intake duct over the range of 100 Hz to 400 Hz, and the radiated sound is reduced by resonance by the resonator 20B. I can understand that. However, in the comparative resonator 20B, since the inner space of the main body case 21 is partitioned by the partition plate 23 in which the communication port 23a is not formed, it matches the resonance frequencies f1, f2, and f3 set in the respective resonance chambers. However, the resonance frequency f1, f2, and f3 are around the resonance frequencies f1, f2, and f3, and a large anti-resonance is generated, resulting in a “mountain” shape, and the noise reduction effect is deteriorated.

  On the other hand, in the evaluation product having the resonator 20S in which the frequency intervals of the resonance frequencies f1, f2, and f3 are approximately 100 Hz, as shown by the solid line in FIG. It can be understood that the acoustic transfer characteristic P2 / P1 is small over the frequency range of 100 Hz to 400 Hz, in other words, the reference sound is satisfactorily reduced by resonance. On the other hand, the deterioration of the noise reduction effect due to the anti-resonance seen in the comparative product is not seen. Therefore, the resonator 20S in which the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 100 Hz has a noise reduction characteristic that satisfactorily reduces noise in a frequency range of 100 Hz to 400 Hz that is desired to be reduced in the vehicle intake system K. It can be said that. In the following description, the resonator 20S in which the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 100 Hz is used as a reference, and in particular, this resonator 20S is also referred to as a reference resonator 20S.

b. In the case where the frequency interval is 50 Hz: The resonator 20S was manufactured by setting parameters so that the frequency interval between the resonance frequencies f1, f2, and f3 was approximately 50 Hz. In setting the parameters at which the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 50 Hz, in this embodiment, as shown in Tables 2 to 4 below, the parameters of the reference resonator 20S are used as references. A resonator 20S was manufactured by changing one of the three parameters of the length L1, the inner diameter D of the communication tube 22, and the internal volume V of each resonance chamber 21b, 21c. Specifically, Table 2 below shows a case where the length L1 of the communication pipe 22 is changed to be longer than the length L1 of the communication pipe 22 in the reference resonator 20S, and Table 3 below shows the inner diameter D of the communication pipe 22. Is changed to be smaller than the inner diameter D of the communication pipe 22 in the reference resonator 20S. Table 4 below shows the internal volume V of the second resonance chamber 21b and the third resonance chamber 21c as the second resonance in the reference resonator 20S. The case where it changes so that it may become larger than the internal volume V of the chamber 21b and the 3rd resonance chamber 21c is shown.

  Thus, in the three resonators 20S in which one of the parameters of the reference resonator 20S is changed and the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 50 Hz, the above equations 1 to 4 are used. From the calculation, it was confirmed that the resonance frequency f2 of the second resonance chamber 21b was approximately 50 Hz larger than the resonance frequency f1 of the first resonance chamber 21a. Moreover, it was confirmed by the calculation using the above formulas 1 to 4 that the resonance frequency f3 of the third resonance chamber 21c is approximately 50 Hz larger than the resonance frequency f2 of the second resonance chamber 21b.

  Then, using the measuring apparatus of FIG. 2, the acoustic transfer characteristics P2 / P1 (three evaluation products in which the three resonators 20S set to the parameters shown in Tables 2 to 4 are assembled to the intake duct 11 respectively. That is, noise reduction characteristics were measured. As these measurement results, the acoustic transfer characteristics P2 / P1 of the evaluation product when the length L1 of the communication pipe 22 is changed and set are shown in FIG. 4, and when the inner diameter D of the communication pipe 22 is changed and set. FIG. 5 shows the acoustic transfer characteristics P2 / P1 of the evaluation product, and the acoustic transfer characteristics P2 // of the evaluation product when the internal volume V of the second resonance chamber 21b and the internal volume V of the third resonance chamber 21c are changed and set. P1 is shown in FIG. In addition, in order to evaluate the acoustic transfer characteristics P2 / P1 of these three evaluation products, for reference, FIGS. 4 to 6 show the acoustic transfer characteristics P2 / P1 of the intake duct indicated by a broken line, and a comparative product indicated by a one-dot chain line. The acoustic transfer characteristic P2 / P1 and the acoustic transfer characteristic P2 / P1 of the evaluation product in which the frequency interval between the resonance frequencies f1, f2, and f3 indicated by the two-dot chain line is approximately 100 Hz are added.

  As is apparent from FIGS. 4 to 6, in the three evaluation products having the resonator 20S in which the frequency intervals of the resonance frequencies f1, f2, and f3 are approximately 50 Hz, as shown by the solid line, the frequency change of the radiated sound is caused. In contrast, it can be understood that the sound transfer characteristic P2 / P1 is generally small between the radiated sound frequencies of 100 Hz to 400 Hz, in other words, that the reference sound is reduced by resonance. However, when compared with the acoustic transfer characteristic P2 / P1 of the evaluation product in which the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 100 Hz, the acoustic transfer characteristic P2 of the intake duct 11 is particularly high in the high frequency range near 400 Hz. / Noise reduction effect is worse than P1.

  As described above, when the frequency interval between the resonance frequencies f1, f2, and f3 is smaller than 100 Hz, the noise reduction effect can be exhibited at a frequency of 100 Hz to 400 Hz, but the noise reduction effect particularly in a high frequency range is deteriorated. For this reason, in this embodiment, the frequency interval of each resonance frequency f1, f2, and f3 is set larger than 50 Hz.

c. When the frequency interval is 150 Hz: Resonator 20S was manufactured by setting parameters so that the frequency interval between the resonance frequencies f1, f2, and f3 was approximately 150 Hz. In setting parameters for the frequency interval between the resonance frequencies f1, f2, and f3 to be approximately 150 Hz, in the present embodiment, as shown in Tables 5 to 7 below, as in the case where the frequency interval is 50 Hz. Further, based on the parameters of the reference resonator 20S as a reference, the resonator 20S is manufactured by changing one of the three parameters of the length L1, the inner diameter D of the communication tube 22 and the internal volume V of each resonance chamber 21b, 21c. did. Specifically, Table 5 below shows a case where the length L1 of the communication pipe 22 is changed to be shorter than the length L1 of the communication pipe 22 in the reference resonator 20S, and Table 6 below shows the inner diameter D of the communication pipe 22. Is changed to be larger than the inner diameter D of the communication tube 22 in the reference resonator 20S, and Table 7 below shows the internal volume V of the second resonance chamber 21b and the third resonance chamber 21c as the second resonance in the reference resonator 20S. The case where it changes so that it may become smaller than the internal volume V of the chamber 21b and the 3rd resonance chamber 21c is shown.

  Thus, in the three resonators 20S in which one of the parameters of the reference resonator 20S is changed and the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 150 Hz, the above equations 1 to 4 are used. According to the calculation, it was confirmed that the resonance frequency f2 of the second resonance chamber 21b was approximately 150 Hz larger than the resonance frequency f1 of the first resonance chamber 21a. Moreover, it was confirmed by the calculation using the formulas 1 to 4 that the resonance frequency f3 of the third resonance chamber 21c is approximately 150 Hz larger than the resonance frequency f2 of the second resonance chamber 21b.

  Then, using the measurement apparatus of FIG. 2, the acoustic transfer characteristics P2 / P1 (three evaluation products in which the three resonators 20S set to the parameters shown in Tables 5 to 7 are assembled to the intake duct 11 respectively. That is, noise reduction characteristics were measured. As these measurement results, the acoustic transfer characteristics P2 / P1 of the evaluation product when the length L1 of the communication pipe 22 is changed and set are shown in FIG. 7, and when the inner diameter D of the communication pipe 22 is changed and set. FIG. 8 shows the acoustic transfer characteristics P2 / P1 of the evaluation product, and the acoustic transfer characteristics P2 // of the evaluation product when the internal volume V of the second resonance chamber 21b and the internal volume V of the third resonance chamber 21c are changed and set. P1 is shown in FIG. Also in this case, in order to evaluate the sound transfer characteristics P2 / P1 of these three evaluation products, for reference, in FIGS. 7 to 9, the sound transfer characteristics P2 / P1 of the intake duct indicated by a broken line are indicated by a one-dot chain line. The acoustic transfer characteristics P2 / P1 of the comparative product shown and the acoustic transfer characteristics P2 / P1 of the evaluation product in which the frequency interval between the resonance frequencies f1, f2, and f3 indicated by the two-dot chain line is approximately 100 Hz are added.

  As is apparent from FIGS. 7 to 9, in the three evaluation products having the resonator 20S in which the frequency intervals of the resonance frequencies f1, f2, and f3 are approximately 150 Hz, as shown by the solid line, the vicinity of 200 Hz is increased from the high frequency side. Towards the sound transfer characteristic P2 / P1, which is smaller than the sound transfer characteristic P2 / P1 of the evaluation product in which the frequency interval between the resonance frequencies f1, f2, f3 is approximately 100 Hz, in other words, the reference sound is more resonant. It can be understood that this is reduced. However, the deterioration of the noise reduction effect due to anti-resonance, which is not seen in the evaluation product in which the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 100 Hz, is seen in the frequency range of 200 Hz or less. From these facts, as the frequency interval between the resonance frequencies f1, f2, and f3 becomes larger than about 100 Hz, the noise reduction effect in the high frequency range tends to be good, but the anti-resonance in the low frequency range. It can be said that the noise reduction effect tends to deteriorate due to the occurrence.

  Further, as is apparent from FIG. 9, when the internal volume V of the second resonance chamber 21b and the internal volume V of the third resonance chamber 21c are set so as to be small, the frequency change of the radiated sound is caused. On the other hand, the overall sound transfer characteristic P2 / P1 tends to increase. This is because the Helmholtz resonator reduces noise by resonance in the resonance chamber, so the size of the internal volume of the resonance chamber is an important factor, and the internal volume V of the second resonance chamber 21b and the third volume When the internal volume V of the resonance chamber 21c is reduced, it is considered that the resonance action is reduced. Therefore, when the internal volume V of the second resonance chamber 21b and the internal volume V of the third resonance chamber 21c are changed so as to increase the frequency interval between the resonance frequencies f1, f2, and f3, noise is reduced. It can be said that the reduction effect tends to be impaired.

d. In the case where the frequency interval is 200 Hz: The resonator 20S is manufactured by setting parameters so that the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 200 Hz. In setting parameters for which the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 200 Hz, in the present embodiment, as in the case where the frequency interval is 50 Hz and 150 Hz, the following Tables 8 to 10 are used. As shown, based on the parameters of the reference resonator 20S, the resonator 20S is changed by changing one of the three parameters of the length L1, the inner diameter D of the communication tube 22 and the internal volume V of each resonance chamber 21b, 21c. Was made. Specifically, as in the case where the frequency interval is 150 Hz, Table 8 below shows a case where the length L1 of the communication pipe 22 is changed to be shorter than the length L1 of the communication pipe 22 in the reference resonator 20S. Table 9 below shows a case where the inner diameter D of the communication pipe 22 is changed to be larger than the inner diameter D of the communication pipe 22 in the reference resonator 20S, and Table 10 below shows the second resonance chamber 21b and the third resonance chamber 21c. The case where the internal volume V is changed to be smaller than the internal volumes V of the second resonance chamber 21b and the third resonance chamber 21c in the reference resonator 20S is shown.

  Thus, in the three resonators 20S in which one of the parameters of the reference resonator 20S is changed and the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 200 Hz, the above equations 1 to 4 are used. According to the calculation, it was confirmed that the resonance frequency f2 of the second resonance chamber 21b was approximately 200 Hz larger than the resonance frequency f1 of the first resonance chamber 21a. Moreover, it was confirmed by the calculation using the formulas 1 to 4 that the resonance frequency f3 of the third resonance chamber 21c is approximately 200 Hz larger than the resonance frequency f2 of the second resonance chamber 21b.

  Then, using the measuring apparatus of FIG. 2, the acoustic transfer characteristics P2 / P1 (three evaluation products in which the three resonators 20S set to the parameters shown in Tables 8 to 10 are assembled to the intake duct 11 respectively. That is, noise reduction characteristics were measured. As these measurement results, the acoustic transmission characteristics P2 / P1 of the evaluation product when the length L1 of the communication pipe 22 is changed and set are shown in FIG. 10, and when the inner diameter D of the communication pipe 22 is changed and set. The acoustic transfer characteristic P2 / P1 of the evaluation product is shown in FIG. 11, and the acoustic transfer characteristic P2 // of the evaluation product when the internal volume V of the second resonance chamber 21b and the internal volume V of the third resonance chamber 21c are changed and set. P1 is shown in FIG. Also in this case, in order to evaluate the acoustic transmission characteristics P2 / P1 of these three evaluation products, for reference, in FIGS. 10 to 12, the acoustic transmission characteristics P2 / P1 of the intake duct indicated by a broken line are indicated by a one-dot chain line. The acoustic transfer characteristics P2 / P1 of the comparative product shown and the acoustic transfer characteristics P2 / P1 of the evaluation product in which the frequency interval between the resonance frequencies f1, f2, and f3 indicated by the two-dot chain line is approximately 100 Hz are added.

  As is apparent from FIGS. 10 to 12, in the three evaluation products having the resonator 20S in which the frequency intervals of the resonance frequencies f1, f2, and f3 are approximately 200 Hz, as shown by the solid lines, the resonance frequencies f1, f2 , F3 has a smaller acoustic transfer characteristic P2 / P1 from the vicinity of 200 Hz toward the high frequency side as compared with the evaluation product in which the frequency interval of f3 is approximately 100 Hz. Can be understood to be reduced by resonance. However, in the frequency range of 200 Hz or less as the frequency of radiated sound, the noise reduction effect due to anti-resonance is significantly worse than the evaluation product in which the frequency intervals of the resonance frequencies f1, f2, and f3 are approximately 100 Hz.

  As is apparent from FIG. 12, when the internal volume V of the second resonance chamber 21b and the internal volume V of the third resonance chamber 21c are changed to be smaller, the resonance frequencies f1, f2, and f3 are changed. Compared with the evaluation product in which the frequency interval is approximately 100 Hz, the acoustic transfer characteristic P2 / P1 is particularly large in the frequency range of 200 Hz or less as the frequency of the radiated sound. Accordingly, when the internal volume V of the second resonance chamber 21b and the internal volume V of the third resonance chamber 21c are reduced as parameters and the frequency intervals of the resonance frequencies f1, f2, and f3 are set to approximately 200 Hz, the noise reduction effect is achieved. Tend to be damaged.

e. In the case where the frequency interval is 250 Hz: The resonator 20S was manufactured by setting parameters so that the frequency interval between the resonance frequencies f1, f2, and f3 was approximately 250 Hz. It should be noted that in setting the parameter that the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 250 Hz, it is no longer possible to change the length L1 of the communication pipe 22 to be small within a practical range. . Therefore, in this case, as shown in Tables 11 and 12 below, the parameter of the reference resonator 20S is used as a reference, and the inner diameter D of the communication tube 22 and the internal volume V of each resonance chamber 21b, 21c are selected from the two parameters. A resonator 20S was manufactured by changing one parameter. Specifically, Table 11 below shows a case where the inner diameter D of the communication pipe 22 is changed to be larger than the inner diameter D of the communication pipe 22 in the reference resonator 20S, and Table 12 below shows the second resonance chamber 21b and the third resonance chamber 21b. The case where the internal volume V of the resonance chamber 21c is changed to be smaller than the internal volumes V of the second resonance chamber 21b and the third resonance chamber 21c in the reference resonator 20S is shown.

  As described above, in the two resonators 20S in which one of the parameters of the reference resonator 20S is changed and the frequency interval between the resonance frequencies f1, f2, and f3 is approximately 250 Hz, the above equations 1 to 4 are used. According to the calculation, it was confirmed that the resonance frequency f2 of the second resonance chamber 21b was approximately 250 Hz larger than the resonance frequency f1 of the first resonance chamber 21a. Moreover, it was confirmed by the calculation using the formulas 1 to 4 that the resonance frequency f3 of the third resonance chamber 21c is approximately 250 Hz larger than the resonance frequency f2 of the second resonance chamber 21b.

  Then, by using the measuring apparatus of FIG. 2, the acoustic transfer characteristics P2 / P1 of two evaluation products in which the two resonators 20S set to the parameters shown in Tables 11 and 12 are assembled to the intake duct 11 respectively. That is, noise reduction characteristics were measured. As these measurement results, the acoustic transfer characteristic P2 / P1 of the evaluation product when the inner diameter D of the communication pipe 22 is changed and set is shown in FIG. 13, and the internal volume V of the second resonance chamber 21b and the third resonance chamber 21c. FIG. 14 shows the acoustic transfer characteristics P2 / P1 of the evaluation product when the internal volume V is changed and set. Also in this case, in order to evaluate the acoustic transfer characteristics P2 / P1 of these two evaluation products, for reference, FIGS. 13 and 14 show the acoustic transfer characteristics P2 / P1 of the intake duct indicated by a broken line by a one-dot chain line. The acoustic transfer characteristics P2 / P1 of the comparative product shown and the acoustic transfer characteristics P2 / P1 of the evaluation product in which the frequency interval between the resonance frequencies f1, f2, and f3 indicated by the two-dot chain line is approximately 100 Hz are added.

  As is apparent from FIGS. 13 and 14, in the evaluation product having the resonator 20S in which the frequency intervals of the resonance frequencies f1, f2, and f3 are approximately 250 Hz, the frequency intervals of the resonance frequencies f1, f2, and f3 described above are set. The tendency to increase the size appears more prominently. That is, as shown in FIG. 13, when the inner diameter D of the communication pipe 22 is changed to be large, the noise reduction effect on the high frequency side near 400 Hz is sufficient as the frequency of the radiated sound, but the radiated sound As the frequency of, the noise reduction effect due to anti-resonance becomes prominent on the low frequency side near 100 Hz. As shown in FIG. 14, when the internal volume V of the second resonance chamber 21b and the third resonance chamber 21c is changed to be small, the noise reduction effect of anti-resonance is around 150 Hz as the frequency of the radiated sound. Deterioration is seen.

  As described above, when the frequency interval between the resonance frequencies f1, f2, and f3 is larger than 200 Hz, the tendency to deteriorate the noise reduction effect in the frequency range of the radiated sound having a frequency of 200 Hz or less appears significantly. In the present embodiment, it is difficult to change the three parameters when the frequency interval between the resonance frequencies f1, f2, and f3 is greater than 200 Hz. Therefore, the frequency interval between the resonance frequencies f1, f2, and f3 is set to be smaller than 200 Hz. Therefore, in the resonator 20 provided in the intake system K, the frequency interval between the resonance frequencies f1, f2, and f3 of the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c is greater than 50 Hz and greater than 200 Hz. Also set within a small range. As a result, the noise reduction characteristics can be appropriately changed according to the required reduction level in the frequency range of 100 Hz to 400 Hz where noise should be reduced.

  As can be understood from the above description, according to this embodiment, the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c are formed in the main body case 21 by the partition plate 23. Noise having frequencies that coincide with the resonance frequencies f1, f2, and f3 corresponding to the respective resonance chambers 21a, 21b, and 21c can be satisfactorily reduced. Further, since the formed resonance chambers 21 a, 21 b, 21 c can communicate with each other through the communication holes 23 a formed in the partition plate 23, one large resonance chamber can be formed in the main body case 21. In addition, noise having a frequency that matches the resonance frequency f0 corresponding to the large resonance chamber can be satisfactorily reduced. Thereby, the noise reduction characteristic which reduces the noise of a wide frequency range (100 Hz-400 Hz) favorably can be exhibited.

  Then, when setting the resonance frequencies f1, f2, and f3 in the resonance chambers 21a, 21b, and 21c formed by the partition plate 23, the frequency intervals of these resonance frequencies f1, f2, and f3 are set in the range of 50 Hz to 200 Hz. By doing so, the noise reduction characteristics can be changed as appropriate. Specifically, as the frequency intervals of the resonance frequencies f1, f2, and f3 are set to be small, noise of 200 Hz or less is mainly effective while exhibiting noise reduction characteristics that favorably reduce noise of 100 Hz to 400 Hz. It is possible to change to noise reduction characteristics that are reduced to a low level. On the other hand, as the frequency interval of the resonance frequency is set to be large, the noise reduction characteristic that effectively reduces the noise of 100 Hz to 400 Hz is exhibited, and the noise reduction characteristic that effectively reduces the noise near 400 Hz is mainly changed. can do. Therefore, for example, the noise reduction characteristics can be appropriately changed in accordance with the required noise reduction level that varies depending on the usage environment of the resonator 20.

  Further, by changing one of the length L1 of the communication pipe 22, the inner diameter D of the communication pipe 22, and the internal volumes V of the second resonance chamber 21b and the third resonance chamber 21c, the partition plate 23 The resonance frequencies f1, f2, and f3 of the formed resonance chambers 21a, 21b, and 21c are set, in other words, the noise reduction characteristics can be changed. Thereby, for example, even when the shape of the resonator 20 is limited due to mounting requirements on the vehicle, the resonance frequencies f1, f2, and f3 can be set relatively easily. Therefore, it is possible to appropriately change the noise reduction characteristic in accordance with the required noise reduction level.

  In carrying out the present invention, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object.

  For example, in the above-described embodiment, the length of the communication tube 22 as a parameter when changing the frequency intervals of the resonance frequencies f1, f2, and f3 of the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c. The length L1, the inner diameter D of the communication pipe, and one of the internal volumes V of the second resonance chamber 21b and the third resonance chamber 21c are changed. In this case, by changing the length L1 of the communication tube 22, the inner diameter D of the communication tube, and the inner volumes V of the first resonance chamber 21a, the second resonance chamber 21b, and the third resonance chamber 21c. The frequency intervals between the resonance frequencies f1, f2, and f3 may be set. Thereby, the frequency interval can be changed more finely.

  In the above embodiment, the resonator 20 is assembled to the intake duct 11 for introducing outside air into the engine 14. And it implemented so that the resonator 20 might reduce the noise which propagates the inside of the intake duct 11 in the case of the introduction of the outside air by the engine 14. However, the present invention is not limited to being implemented by assembling the resonator 20 to the intake duct 11 for introducing outside air to the engine 14 as described above. For example, in an air conditioner that air-conditions a passenger compartment, noise may propagate through the air-conditioning duct and radiate in accordance with the operation of the air-conditioner. For this reason, it is also possible to assemble and implement the resonator 20 to the air conditioning duct assembled to such an air conditioner. Even in this case, the resonator 20 can effectively reduce noise in a desired frequency range.

  Furthermore, in the said embodiment, the resonator 20 was comprised and comprised so that it might have three resonance chambers, the 1st resonance chamber 21a, the 2nd resonance chamber 21b, and the 3rd resonance chamber 21c. However, the number of resonance chambers of the resonator is not limited as long as it is plural, and it can be configured to have two resonance chambers or to have four or more resonance chambers. There is no.

It is the schematic which shows the state which applied the resonator which concerns on embodiment of this invention to the intake system of a vehicle. It is a figure for demonstrating the measuring apparatus for measuring an acoustic transfer characteristic. It is a graph which shows the change of the acoustic transfer characteristic with respect to the change of the frequency of a radiated sound when a frequency interval is 100 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the length of a communicating tube and making a frequency interval into 50 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the internal diameter of a communicating pipe and making a frequency interval into 50 Hz. It is a graph which shows the change of the acoustic transfer characteristic with respect to the change of the frequency of a radiated sound when changing the internal volume of a 2nd resonance chamber and a 3rd resonance chamber, and making a frequency interval into 50 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the length of a communicating pipe | tube and making a frequency interval into 150 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the internal diameter of a communicating pipe and making a frequency interval into 150 Hz. It is a graph which shows the change of the acoustic transfer characteristic with respect to the change of the frequency of a radiated sound when the internal volume of a 2nd resonance chamber and a 3rd resonance chamber is changed, and a frequency interval is 150 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the length of a communicating pipe and making a frequency interval into 200 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the internal diameter of a communicating pipe and making a frequency interval 200Hz. It is a graph which shows the change of the acoustic transfer characteristic with respect to the change of the frequency of a radiated sound when the internal volume of a 2nd resonance chamber and a 3rd resonance chamber is changed, and a frequency interval is set to 200 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the internal diameter of a communicating pipe and making a frequency interval into 250 Hz. It is a graph which shows the change of the acoustic transmission characteristic with respect to the change of the frequency of a radiated sound when changing the internal volume of a 2nd resonance chamber and a 3rd resonance chamber, and making a frequency interval into 250 Hz.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Intake duct, 12 ... Air cleaner, 13 ... Air cleaner hose, 14 ... Engine, 15 ... Throttle body, 20 ... Resonator, 21 ... Main body case, 21a ... First resonance chamber, 21b ... Second resonance chamber, 21c ... Third Resonance chamber, 22 ... communication pipe, 23 ... partition plate, 23a ... communication hole

Claims (3)

A main body case that is disposed outside a tubular body through which gas can pass and divides a predetermined internal volume, a communication pipe that connects the tubular body and the main body case in a communication state, and a main body case disposed in the main body case. And a partition member that divides the inside of the main body case into a plurality of resonance chambers and has a partition member formed with a communication hole that allows the plurality of resonance chambers to communicate with each other.
A resonator, wherein each resonance frequency corresponding to the plurality of resonance chambers is set to have a predetermined frequency interval. The resonator according to claim 1,
The predetermined frequency interval is
A resonator having a frequency interval larger than 50 Hz and smaller than 200 Hz. The resonator according to claim 1,
Each resonance frequency corresponding to the plurality of resonance chambers is:
By setting at least one of the length of the communication pipe, the inner diameter of the communication pipe, and the internal volumes of the plurality of resonance chambers, the predetermined frequency interval is set. Resonator to do.

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