JP2006064822A - Tire cavity resonance sound reducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire cavity resonance sound reducing device which effectively reduces cavity resonance sound dynamically being varied by road conditions or the like and is large in applicable scope. <P>SOLUTION: The tire cavity resonance sound reducing device consists of: a microphone 1a which collects sound in an air room; an FFT analyzing means 13 which analyzes the collected sound and obtains the frequency and the strength of the sound that causes cavity resonance; a synthesized sound data generating means 14 which generates data to synthesize sound having the same frequency and the same strength as the obtained frequency; a phase adjusting means 15 which adjusts the phase based on the generated data when the sound is outputted so as to make canceling sound; and a speaker 1d which outputs the phase adjusted canceling sound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tire cavity resonance reduction device that reduces and reduces road noise (tire cavity resonance) generated during traveling of a vehicle with synthesized sound.

  The noise in the passenger compartment caused by road surface irregularities while the vehicle is traveling is called road noise. One factor of this road noise is tire cavity resonance sound having a peak around 200 to 300 Hz (hereinafter, “tire cavity resonance” is abbreviated as “cavity resonance” as appropriate). Conventionally, in order to reduce this road noise, a secondary air chamber that absorbs vibration in a frequency band corresponding to a cavity resonance frequency has been formed in an air chamber formed between a tire and a wheel rim. (See Patent Document 1 and Patent Document 2). Among these, the “rim wheel” of Patent Document 1 has a plurality of lid members arranged in the circumferential direction on the outer peripheral surface of the rim and provided with a partition wall inside the lid member, whereby a plurality of lid members are provided between the rim and the lid member. Are formed in the circumferential direction so as to absorb and reduce cavity resonance noise.

In addition, other technologies such as adjusting the tire pressure, adjusting the tire pattern, placing rubber bushes that do not transmit noise and vibration to the suspension, and stretching vibration-proofing materials on the vehicle body side, etc. Proposed.
JP 2002-79802 (paragraph 0019, abstract, etc.) JP 2003-326907 A (Claims etc.)

  However, vehicles, suspensions, tires, air pressure, road surfaces, driving modes, and the like are various, and it is difficult to deal with all of them with the above-described technology. Further, with the above-described technique, it is almost impossible to reduce cavity resonance in real time in response to changing road surface conditions.

  Therefore, an object of the present invention is to provide a tire cavity resonance noise reduction device that can effectively reduce cavity resonance noise that varies depending on road surface conditions and the like, and has a wide application range.

The present invention that has solved the above problems is a tire cavity resonance noise reducing device that reduces the cavity resonance noise by outputting a cancellation noise that cancels the cavity resonance noise in the air chamber of the tire into the air chamber, Sound collecting means for collecting sound in the air chamber, and resonance sound analyzing means (load) for analyzing the sound collected by the sound collecting means to obtain the frequency and intensity of the sound that causes the cavity resonance sound (road noise) Noise analyzing means), synthesized sound data generating means for generating data for synthesizing a sound having the same frequency as the frequency obtained by the resonance sound analyzing means, and data generated by the synthesized sound data generating means. A phase adjusting unit that adjusts a phase when outputting sound based on the phase adjustment unit to make a canceling sound, and a canceling sound output unit that outputs the canceling sound adjusted by the phase adjusting unit. You .
According to this configuration, the sound in the air chamber is collected, analyzed, the sound is synthesized, the phase is adjusted, and the result is output to the air chamber as a canceling sound, so that the cavity resonance sound (road noise) is dynamically generated. Reduce.

According to a second aspect of the present invention, the resonance sound analysis means, the synthesized sound data generation means, and the phase adjustment means are incorporated in a wheel side sensor unit of a tire air pressure detection system that detects tire air pressure. To do.
That is, in this configuration, as shown in a second embodiment or a third embodiment to be described later, the tire cavity resonance noise reduction device is integrated with the wheel side sensor unit of the tire pressure monitoring system.

According to a third aspect of the present invention, the tire cavity resonance reduction device further includes a radio wave receiving unit, and the phase adjusting unit receives a phase adjustment signal (manual phase) received through the radio wave receiving unit. The phase is adjusted by an adjustment signal).
That is, in this configuration, as shown in a third embodiment described later, the phase of the canceling sound is adjusted wirelessly.

  According to the first aspect of the present invention, it is possible to provide a tire cavity resonance noise reduction device that can effectively reduce cavity resonance noise that varies depending on air pressure, road surface conditions, and the like, and has a wide application range. According to claim 2, it is possible to divert the function of a tire pressure monitoring system that is expected to be widely used in the future, and it is possible to reduce the size of the apparatus, for example. According to the third aspect, the occupant or the like can instruct the tire cavity resonance noise reduction device to reduce the cavity resonance noise taking into account human sensitivity while running, for example.

  Hereinafter, the best mode (hereinafter referred to as “embodiment”) for carrying out the tire cavity resonance noise reducing device of the present invention will be described in detail with reference to the drawings.

<< Principle of the present invention >>
First, the principle of the present invention will be described with reference to FIG.
FIG. 1 (a) shows the principle of canceling the sound of the sound source by the canceling sound, FIG. 1 (b) shows the frequency characteristics of the sound of the sound source, and FIG. 1 (c) shows the sound causing the noise and the canceling. A shining sound is shown.

  As shown in FIG. 1A, the sound (noise) of the sound source is collected in step S1, analyzed in step S2, and the peak frequency (frequency X of the sound causing the noise) and its intensity are obtained. In step S3, data for synthesizing a sound having the same frequency and the same intensity as the frequency X obtained in step S2 is generated. In step S4, the phase when the sound is output is adjusted based on the generated data. Thus, the canceling sound is output, and the canceling sound whose phase is adjusted in step S5 is output toward the noise.

  The frequency characteristic of the sound of the sound source analyzed in step S2 is shown in FIG. 1B, and has a peak at the frequency X portion. In FIG. 1 (c), the sound of frequency X is shown by a solid line and the canceling sound is shown by a broken line, but the two are 180 degrees out of phase so that the sound intensity is weakened. The sound intensity of the sound source is reduced (disappeared) (in FIG. 1B, the peak height of the frequency X is reduced).

<< First Embodiment >>
Next, a first embodiment of the tire cavity resonance noise reducing device of the present invention will be described. FIG. 2 is a perspective view of a vehicle to which the tire cavity resonance reduction device of the first embodiment is applied.

  The road noise is generated by the traveling of the vehicle C as described above. Among the road noises, one of the factors causing discomfort to the occupant is tire cavity resonance generated in an air chamber inside the tire T. In the present embodiment, road noise (cavity resonance) generated by traveling of the vehicle C is reduced (eliminated) by canceling with the tire cavity resonance reduction device 1.

[Configuration of tire cavity resonance noise reduction device, etc.]
Fig.3 (a) is a figure which shows the tire cavity resonance noise reduction apparatus of the state with which the wheel was mounted | worn. As shown in FIG. 3A, the tire cavity resonance reduction device 1 is mounted on the rim outer peripheral surface of the wheel W using a valve mounting hole (not shown). As understood from this figure, the tire cavity resonance reduction device 1 is disposed in an air chamber formed by the tire T and the rim outer peripheral surface.

  FIG.3 (b) is a figure which shows the external appearance of a tire cavity resonance noise reduction apparatus. As shown in FIG. 3 (b), the tire cavity resonance sound reducing device 1 is formed integrally with a valve used when air is injected into the air chamber, and is not shown in the figure. It is designed to be installed in the valve mounting hole. Here, the tire cavity resonance noise reduction device 1 has a similar curved surface so that the bottom surface follows the curved surface of the rim outer peripheral surface so that the tire cavity resonance noise reducing device 1 can be in close contact with the rim outer peripheral surface.

  Further, the tire cavity resonance noise reducing device 1 includes a microphone 1a, an arithmetic processing unit 10 indicated by a broken line, a speaker 1d, a power source (not shown), and the like in a single casing.

  FIG. 4A is a block configuration diagram showing an internal configuration of the tire cavity resonance reduction device shown in FIG. As shown in FIG. 4 (a), the tire cavity resonance sound reducing device 1 is a microphone 1a that collects road noise, and an analog signal that is output when the microphone 1a collects road noise into a digital signal to generate sound data. The AD converter 1b, the arithmetic processing means 10, the DA converter 1c that converts the digital signal of the canceling sound output from the arithmetic processing means 10 into an analog signal, and the speaker that outputs the canceling sound toward the sound source (in the air chamber) 1d etc. are comprised.

  Among the above-described components, the arithmetic processing means 10 includes an input interface 11, data storage means 12, FFT (Fast Fourier Transform) analysis means 13, synthesized sound data generation means 14, phase adjustment means 15, output interface 16, and the like. Consists of.

  Among these, the data storage means 12 stores digitized sound data in a FIFO (First In First Out) 121 which is a first-in first-out memory. It is assumed that the number of data necessary for the FFT analysis means 13 to perform the FFT analysis is stored in the FIFO 121 in a first-in first-out manner. The FFT analysis unit 13 reads the sound data stored in the data storage unit 12 and performs processing (frequency analysis) for extracting which frequency component is included in the read sound data. Then, processing for obtaining the frequency and intensity of the sound causing the cavity resonance sound is performed in the vicinity of 250 Hz among the analyzed frequency components (see FIG. 4B described later). The synthesized sound data generating means 14 generates sound data (synthesized sound data) necessary for outputting a sound having the same frequency as the cause of the sound obtained by the FFT analyzing means 13 with the same intensity as the obtained intensity. Generate. In this embodiment, as described later, synthesized sound data of two frequencies (synthesized sound data of frequency A and synthesized sound data of frequency B) is generated. The phase adjusting unit 15 is a unit that adjusts the phase so that the output sound becomes a canceling sound when outputting the synthesized sound data (phase adjustment of the canceling sound). As a method of adjusting the phase by the phase adjusting means 15, for example, the synthesized sound data is temporarily stored in a memory such as the above-described FIFO, and the synthesized sound data stored with a delay time is provided. This can be realized by outputting.

[Frequency characteristics of road noise (cavity resonance)]
FIG. 4B is a diagram showing the frequency characteristics of road noise analyzed by the FFT analysis means of FIG. In FIG. 4B, the sound of the frequency A slightly higher than 250 Hz and the sound of the frequency B slightly lower cause the cavity resonance. Incidentally, the FFT analysis means 13 has a logic that finds a frequency peaking in the vicinity of 250 Hz and recognizes this as a sound that causes the cavity resonance. In addition, what is shown with the broken line is the frequency characteristic after cancellation.

[Canceling sound]
FIG. 4C is a diagram illustrating waveforms of the cavity resonance sound and the cancellation sound. In the upper diagram of FIG. 4C, the solid line shows the waveform of the sound of frequency A that is the cavity resonance sound, and the broken line shows the waveform of the first cancellation sound for canceling the sound of frequency A. Yes. In the lower diagram of FIG. 4C, the solid line indicates the waveform of the sound of frequency B that is the cavity resonance sound, and the broken line indicates the waveform of the second cancellation sound for canceling the sound of frequency B. ing.

  The upper diagram in FIG. 4C shows a state in which the phase of the frequency A and the canceling sound are 180 degrees out of phase as a result of the phase adjustment by the phase adjustment means 15. In such a case, the first canceling sound acts as a canceling sound, and it is possible to cancel the sound of frequency A.

  On the other hand, in the lower diagram in FIG. 4C, the phase shift between the sound of the frequency B and the second canceling sound is not 180 degrees. In such a case, since the second canceling sound cannot sufficiently act as a canceling sound, phase adjustment by the phase adjusting means 15 is necessary.

[Operation of tire cavity resonance reduction device]
Next, the operation of the tire cavity resonance reduction device 1 of the present embodiment will be described along the flowchart of FIG. 5 with reference to FIGS. Note that the processing shown in this flowchart is repeatedly executed by the arithmetic processing means 10 of the tire cavity resonance reduction device 1.

  Processing starts in step S10. The sound (road noise) in the air chamber collected by the microphone 1a of the tire cavity resonance reduction device 1 is digitized as sound data by the AD converter 1b. The input interface 11 inputs the digitized sound data (S11). The input sound data is stored in the FIFO 121 by the data storage means 12 (S12).

  It is determined whether or not sound data having a number of data sufficient for frequency analysis is stored in the FIFO 121 by the FFT analysis means 13 (S13). If the number of data is insufficient (No), the process proceeds to step S21, and then step S10. To start processing. Thereby, the sound data is stored in the FIFO 121.

  If the number of data is OK in step S13 (Yes), it is determined whether or not sound data is read from the FIFO 121 (S14, that is, whether or not frequency analysis is performed). If it is read (Yes), FFT is performed. Sound data of the number of data necessary for the analysis means 13 to perform frequency analysis is read from the FIFO 121 (S15). On the other hand, when not reading (No), the process proceeds to step S21, and then the process starts in step S10. As a result, new sound data is stored in the FIFO 121, and the oldest data among the stored sound data is discarded. As a result, the FIFO 121 always stores voice data in a fresh state necessary for the FFT analysis means 13 to perform frequency analysis, and can appropriately deal with dynamically changing cavity resonance sound. Incidentally, if the number of times of Yes in step S14 is increased, the cavity resonance noise can be appropriately reduced even when the road surface condition dynamically changes. On the other hand, if the number of times of No in step S14 is increased, the number of calculations in the calculation processing means 10 is reduced, so that power consumption can be reduced.

  The FFT analysis unit 13 performs a process of extracting which frequency component is included by performing a fast Fourier transform (FFT) process on the audio data read from the data storage unit 12. Then, of the frequency components, the frequency of the sound that causes the cavity resonance sound and the intensity thereof are obtained in the vicinity of 250 Hz (S16). In the example of FIG. 4B, the peaks A and B are obtained, and the intensity of the peak is obtained.

  When the frequency and its intensity are obtained, the synthesized sound data generating means 14 generates synthesized sound data for generating a sound having the same frequency and the same intensity as those obtained in step S16 (S17). In the example of FIG. 4B, synthesized sound data for the frequencies A and B is generated as indicated by broken lines in FIG.

  Next, it is determined whether or not phase adjustment is necessary (S18). If it is not necessary (No), phase adjustment is not performed, that is, the phase is the same as the previous value. Incidentally, it is assumed that the initial value of the phase is zero. On the other hand, when the phase adjustment is necessary (Yes), the phase adjustment unit 15 adjusts the phase by a predetermined angle (phase adjustment amount) of the wavelength period. Incidentally, in the example of FIG. 4B, the phase adjustment is performed independently for the frequencies A and B. For this reason, the phase adjustment means 15 shall be comprised so that the phase adjustment of several synthetic sound data can be performed independently. In this embodiment, the phase adjustment amount is set to 5 degrees or 10 degrees in advance.

  Note that the phase adjustment is necessary when, for example, the intensity of the sound analyzed by the FFT analysis means 13 is increased from the previous value (increased by a threshold value) or the intensity of the sound is equal to or longer than a predetermined time (predetermined calculation). This is the case when it is at a higher level. Of course, in such a case, the phase is adjusted in the direction in which the intensity decreases.

  Whether or not the phase is adjusted, the synthesized sound data that becomes the canceling sound is output via the output interface 16 (S20), converted into an analog signal by the DA converter 1c, and output as a sound from the speaker 1d. Incidentally, the canceling sound is a synthesized sound having a peak at frequencies A and B (see FIG. 4B). As a result, the strength of each other is weakened, and the cavity resonance noise is reduced as shown by the broken line in FIG.

  When the process finishes step S20, the process returns to step S10 via step S21 to continue the process. From the next time onward, the FIFO 121 stores sound data that can be frequency-analyzed by the FFT analysis means 13, so that the step S13 becomes Yes. Then, in step S14, it is determined whether or not to read data, that is, whether or not frequency analysis is performed. If so (if S14 is Yes), the processing after step S16 is performed, and a new one is performed. A canceling sound is output based on accurate frequency analysis (S20). Incidentally, when Step S14 is No, the same canceling sound output state as the previous time is maintained.

  According to the first embodiment, since the cavity resonance sound is collected and analyzed by the tire cavity resonance reduction device 1 arranged in the air chamber, and the canceling sound is output to the air chamber, the cavity resonance is directly generated. Sound can be reduced. Also, since the tone, intensity, and phase of the canceling sound are dynamically changed constantly, even when the road surface condition and the driving mode change dynamically, the cavity resonance sound can be effectively reduced by appropriately dealing with it. Can do. Further, it is possible to provide the tire cavity resonance noise reduction device 1 having a wide application range that can cope with different vehicles, suspensions, tires, and air pressures.

<< Second Embodiment >>
Then, 2nd Embodiment of the tire cavity resonance noise reduction apparatus of this invention is described. FIG. 6 shows a perspective view of a vehicle to which the tire cavity resonance reduction device of the second embodiment is applied. In the second embodiment, parts common to the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the tire cavity resonance reduction device 1 ′ of the second embodiment also serves as a sensor unit (wheel side sensor unit) of a tire pressure monitoring system (TPMS [Tire Pressure Monitoring System]) S, The tire cavity resonance noise reduction device 1 ′ and the in-vehicle unit 8 mounted on the vehicle C constitute a tire air pressure monitoring system S.

  FIG. 7 shows the configuration of the tire cavity resonance reduction device 1 ′ according to the second embodiment. As shown in FIG. 7, the arithmetic processing means 10 ′ includes a microphone 1a, a speaker 1d, a pressure sensor 1e, and a temperature sensor 1f. A power source 1g and an antenna are connected.

  In addition to the functions provided in the arithmetic processing means 10 (see FIG. 4) of the first embodiment, the arithmetic processing means 10 ′ is a function of the tire air pressure monitoring system S, and the pressure in the air chamber detected by the pressure sensor 1e, It has a function of attaching a unique ID to the temperature in the air chamber detected by the temperature sensor 1 f and transmitting it from the antenna to the in-vehicle unit 8. That is, in the second embodiment, the above-described FFT analysis means 13, the synthesized sound data generation means 13 and the phase adjustment means 14 are built in the sensor unit (referred to as CPU [Central Processing Unit]). Common).

Since other configurations are the same as those of the first embodiment, description thereof is omitted.
According to the second embodiment, the CPU power of the sensor unit of the tire pressure monitoring system S can be used. Moreover, the power supply 1g can be utilized. Such sharing makes it possible to keep cost and size increase low.

  The present invention described above is not limited to the above-described embodiment, and can be widely modified (see FIGS. 1 to 7).

  For example, although an example in which one speaker is provided has been described, a plurality of speakers 1d may be provided at appropriate intervals in the circumferential direction of the rim outer peripheral surface in consideration of wheel balance and the like. In addition, the tire cavity resonance noise reduction device 1 is mounted on the rim outer peripheral surface of the wheel W using the valve mounting hole, but other mounting methods such as welding, bonding, band fastening, and screw fastening are applied. Also good. Then, a sensor unit of another housing (separate housing from the tire cavity resonance reduction device 1) used in the tire pressure monitoring system S is provided on the outer peripheral surface of the rim by using the vacant valve mounting hole. Also good. In this case, it is preferable to determine the position where the tire cavity resonance reduction device 1 is provided while considering the balance of the wheel W.

  In the above-described embodiment, the phase adjustment unit 14 automatically performs the phase adjustment based on the analysis result of the FFT analysis unit 13. However, the present invention is not limited to being performed automatically. For example, an operation unit that allows a person to adjust the phase may be provided in the phase adjustment unit 15 so that it can be performed by a human hand. Even in this case, when the driving mode or the road surface condition changes, it is possible to cope with the reduction of the cavity resonance sound although it is manual. In addition, since adjustments can be made according to human sensitivity, the number of tuning steps during development can be reduced. In addition, means for allowing a person to adjust the frequency (tone color) and sound intensity of the synthesized sound data is provided so that human sensitivity can be added to the synthesized sound data generated by the synthesized sound data generating means 14. Also good.

  Alternatively, the microphone 1a and the speaker 1d may be provided in the air chamber (rim outer peripheral surface), the arithmetic processing means 10 and the power source may be provided in the center of rotation of the wheel W, and connected by wiring. By doing so, it is possible to easily replace the battery as a power source, and to easily balance the wheel.

  Further, the microphone 1a and / or the speaker 1d are also provided at the center of rotation of the wheel W, and the sound waveguide is communicated with the air chamber to collect the sound and / or output the canceling sound (via the waveguide). Output of a canceling sound into the air chamber.

<< Third Embodiment >>
Finally, a third embodiment in which the phase of the canceling sound can be adjusted while traveling by the hand of an occupant (maintenance staff / developer ...) will be described with reference to FIGS. . In addition, the same code | symbol is attached | subjected to the part which is common in above-described 1st Embodiment and 2nd Embodiment, and description is abbreviate | omitted.

  FIG. 8 is a diagram showing the configuration of the tire cavity resonance reduction device of the third embodiment. As shown in FIG. 8, the tire cavity resonance reduction device 1 ″ is different from the tire cavity resonance reduction device 1 of the first embodiment (see FIG. 4A) in that the pressure sensor 1e, the temperature sensor 1f, A reception antenna, an RF receiver (radio wave receiving means) 1h, an RF transmitter 1i, an antenna for transmission, etc. are added, and the antenna may be used for both transmission and reception. 1e, the temperature sensor 1f, the RF receiver 1h, and the RF transmitter 1i may be provided by the sensor unit of the tire pressure monitoring system S (see FIG. 6) as an original configuration. Is an abbreviation for "."

  Also, the FFT analysis means 13 ″ of the arithmetic processing means 10 ″ provides a sound frequency (peak frequency) that causes cavity resonance and a signal of its intensity via the RF transmitter 1i, which will be described later in FIG. It is configured to send to '. The phase adjustment means 15 ″ receives and acquires a manual phase adjustment signal (not shown) transmitted from the in-vehicle unit 8 ′ via the RF receiver 1h, and cancels it based on the acquired manual phase adjustment signal. In addition, the TPMS processing means 17 of the arithmetic processing means 10 ″ adjusts the pressure signal detected by the pressure sensor 1e and the temperature signal detected by the temperature sensor 1f to the RF transmitter 1i. Is transmitted to the in-vehicle unit 8 ′ at a predetermined timing. Incidentally, the TPMS processing means 17 may be provided as an original configuration of the sensor unit of the tire pressure monitoring system S.

  FIG. 9 is a diagram illustrating a configuration of an in-vehicle unit that transmits a manual phase adjustment signal for adjusting the phase of the canceling sound to the tire cavity resonance sound reducing device of FIG. 8. As shown in FIG. 9, the in-vehicle unit 8 'includes a keyboard 8a, a receiving antenna, an RF receiver 8b, a monitor 8c, an RF transmitter 8d, a transmitting antenna and arithmetic processing means 80'. Note that the antenna may be used for both transmission and reception. Incidentally, the antenna, the RF receiver 8b, and the RF transmitter 8d may be provided as the original configuration of the in-vehicle unit 8 (see FIG. 6) of the tire pressure monitoring system S.

  The arithmetic processing unit 80 ′ includes an input interface 81, a processing unit 82, and an output interface 83. Among these, the processing means 82 performs a process of performing a pressure drop determination based on the pressure signal and the temperature signal received via the RF receiver 8b and displaying them on the monitor 8c, and also a cavity received via the RF receiver 8b. Processing for processing the signal of the frequency and intensity of the sound causing resonance and displaying it on the monitor 8c, and a manual phase adjustment signal transmitted to the cavity resonance sound reducing device 1 "based on key inputs from the occupant or the like from the keyboard 8a The process which produces | generates is performed.

According to the third embodiment having such a configuration, the in-vehicle unit 8 ′ performs the air pressure decrease determination based on the pressure signal and the temperature signal transmitted from the tire cavity resonance reduction device 1 ″, and FIG. As shown, the determination result is displayed on the monitor 8c, so that an occupant or the like can know a decrease in the air pressure of the tire T even while the vehicle C is traveling.
Further, this in-vehicle unit 8 'displays the sound frequency and intensity signal that cause the cavity resonance transmitted from the tire cavity resonance reduction device 1 "on the monitor 8c as shown in FIG. For this reason, an occupant or the like can know the generation state of the cavity resonance sound, which is shown in Fig. 9. In Fig. 9, the monitor 8c generates the cavity resonance sound of one tire T among the four tires T. The situation is displayed numerically and the air pressure conditions of the four tires are visually displayed.

  As shown in FIG. 9, the occupant or the like can know the frequency and intensity of the sound that causes the cavity resonance, and the keyboard 8a is operated with reference to this, and the phase of the canceling sound for each tire. An instruction for adjustment (frequency and phase adjustment amount (phase adjustment angle)) can be key-inputted, whereby the in-vehicle unit 8 ′ generates a manual phase adjustment signal for each tire by the processing means 82, and RF This is transmitted to the tire cavity resonance reduction device 1 "via the transmitter 8d. Thereby, each tire cavity resonance reduction device 1" receives the corresponding manual phase adjustment signal via the RF receiver 1h and adjusts it. The means 15 ″ adjusts the phase of the canceling sound by the amount indicated by the manual phase adjustment signal (phase adjustment amount). In other words, the occupant or the like adjusts the tire cavity resonance sound reducing device 1 ″ of each tire T Manual canceling sound Can be adjusted to phases, it is possible to reduce the running while cavity resonance in consideration of human sensitivity.

  Of course, a configuration in which the frequency (tone color) can be manually adjusted following the example of phase adjustment described above is simple because the frequency of the synthesized sound to be synthesized by the synthesized sound data generating unit 14 is simply indicated by radio. Can be realized. Further, it is possible to easily realize a configuration in which the intensity of the synthesized sound is instructed wirelessly. In addition, when performing various instructions, it is possible to easily realize a configuration in which key input can be intuitively performed using a GUI (Graphical User Interface). Note that the in-vehicle unit 8 ′ can determine which tire has the air pressure and which tire has the cavity resonance sound by attaching and receiving a signal with an ID. In addition, when the in-vehicle unit 8 ′ includes four receiving antennas close to each tire, which antenna receives the strong radio wave, which tire pressure is, and which tire cavity resonance sound Can be determined.

  Thus, by adopting a configuration in which the phase, frequency, and the like can be manually adjusted, the development cost and tuning cost of the device can be reduced. In addition, the arithmetic processing means 10 ″ of the tire cavity resonance reduction device 1 ″ has the functions of the TPMS and the cavity resonance noise reduction integrated into one chip, thereby further reducing the size and waste of the device. Can do. Of course, the third embodiment may be implemented separately from TPMS.

  In addition, this invention is not limited to a cavity resonance sound, As a road noise reduction apparatus, it can apply in order to reduce general road noise.

It is a figure explaining the principle of this invention, (a) has shown the principle which cancels out the sound of a sound source with a cancellation sound, (b) has shown the frequency characteristic of the sound of a sound source, (c) is noise This shows the sound and the canceling sound. 1 is a perspective view of a vehicle to which a tire cavity resonance noise reduction device according to a first embodiment is applied. (A) is a figure which shows the tire cavity resonance noise reduction apparatus of the state with which the wheel was mounted | worn. (B) is a figure which shows the external appearance of a tire cavity resonance noise reduction apparatus. (A) is a block block diagram which shows the internal structure of the tire cavity resonance noise reduction apparatus shown in FIG. (B) is a figure which shows the frequency characteristic of the road noise analyzed by the FFT analysis means of (a). (C) is a figure which shows the waveform of a cavity resonance sound and a cancellation sound. It is a flowchart which shows operation | movement of the tire cavity resonance noise reduction apparatus of 1st Embodiment. The perspective view of the vehicle to which the tire cavity resonance noise reduction apparatus of 2nd Embodiment was applied is shown. It is a figure which shows the structure of the tire cavity resonance noise reduction apparatus of 2nd Embodiment. It is a figure which shows the structure of the tire cavity resonance noise reduction apparatus of 3rd Embodiment. It is a figure which shows the structure of the vehicle-mounted unit which transmits the manual phase adjustment signal which adjusts the phase of a cancellation sound to the tire cavity resonance sound reduction apparatus of FIG.

Explanation of symbols

1.1 '· 1 "... Tire cavity resonance reduction device 1a ... Microphone (sound collecting means)
1d. Speaker (mating sound output means)
1h RF receiver (radio wave receiving means)
13 ... FFT analysis means (resonance sound analysis means)
14 ... Synthetic sound data generating means 15 ... Phase adjusting means 10 · 10 '· 10 "... Arithmetic processing means

Claims (3)

A tire cavity resonance reduction device that reduces the cavity resonance by outputting a cancellation sound that cancels the cavity resonance in the air chamber of the tire into the air chamber,
Sound collecting means for collecting sound in the air chamber;
Resonance sound analysis means for analyzing the sound collected by the sound collection means to determine the frequency and intensity of the sound causing the cavity resonance;
A synthesized sound data generating means for generating data for synthesizing a sound of the same intensity at the same frequency as the frequency obtained by the resonance sound analyzing means;
Phase adjusting means for adjusting the phase when outputting sound based on the data generated by the synthesized sound data generating means and making it a canceling sound;
A tire cavity resonance reduction device comprising a cancellation sound output means for outputting a cancellation sound adjusted by the phase adjustment means. The said resonance sound analysis means, the said synthetic sound data generation means, and the said phase adjustment means are incorporated in the wheel side sensor unit of the tire pressure detection system which detects the tire pressure. Tire cavity resonance noise reduction device. It further includes a radio wave receiving means for receiving radio waves,
3. The tire cavity resonance noise reduction according to claim 1, wherein the phase adjusting unit adjusts the phase based on a phase adjustment signal received through the radio wave receiving unit. apparatus.

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